Communicable E018: Nightmare series, pt 4, rubella & polio
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[00:00:07] Angela: Hello, and welcome back to Communicable, the podcast brought to you by CMI Communications, Eskmit's open access journal covering infectious diseases and clinical microbiology. It's Angela Huttner here, I'm an infectious disease doctor at the Geneva University Hospital in Switzerland, and editor in chief of CMI Comms.

[00:00:27] Angela: We are coming back to our nightmare series today, though we really didn't want to. Anti vax sentiment in the US and elsewhere is surging. The reality is that people soon to be in power in a powerful nation are questioning the value of many vaccines. A lawyer to the man who will likely be the United States Secretary of Health has asked that approval of the polio vaccine be revoked in that country.

[00:00:53] Angela: The destruction wrought by the poliovirus was well documented and well lived by our predecessors, but most people alive today have not seen polio or rubella, and most doctors in practice today have never handled a case. So for this episode of Communicable, we've brought together two expert infectious disease clinicians who have.

[00:01:15] Angela: With them, we'll go through the basics of these two viral diseases that are rarely seen in most places today. Our first guest is Professor Bernard Hirschel, Professor Emeritus of Infectious Diseases at the University of Geneva, here in Switzerland, and former head of the Geneva University Hospitals HIV unit.

[00:01:33] Angela: And full disclosure, Bernard was once my boss, and was and is an important mentor to me. He also happens to be the physician who treated the last known case of polio in Switzerland. And although he is officially an adult ID doc, as a fourth year medical student working in Cameroon, he worked in a pediatric ward during an epidemic of polio and measles.

[00:01:57] Bernard: Hello. Pleased to be here.

[00:01:59] Angela: Thanks, Dana, for being here. Our second guest is Dr. Kerrigan McCarthy, a clinical microbiologist and pathologist in Johannesburg, South Africa, where a large rubella outbreak is ongoing. Kerrigan is based in the Center for Vaccines and Immunology at South Africa's National Institute for Communicable Diseases.

[00:02:17] Angela: Her responsibilities include surveillance, epidemiology, and laboratory diagnostics, and outbreak investigations for measles, rubella, and rubella. Polio and hepatitis viruses and surveillance includes leading the NICD's Wastewater Surveillance Team. Have a look at our recent episode on wastewater surveillance.

[00:02:36] Angela: Kerrigan, really happy you could join.

[00:02:38] Kerrigan: Wonderful to be with you, Angela and Bernard.

[00:02:41] Angela: Thanks again for being here as our listeners know, we start these episodes with a sort of get to know you question .

I'm going to give a really obvious one because it's January. my question is, what is one of your New Year's resolutions for 2025? So I'll start with mine. I usually have all these resolutions and I'm super ambitious and then I don't really achieve any of them.

[00:03:02] Angela: So this time I thought, okay, I'll just do one. , . And mine is to sort of be instead of do all the time. So be in the moment, but also at the same time, learn to let go the moment. We'll see how it goes.

Bernard. How about you?

[00:03:19] Bernard: Well, we're talking about polio, so there is this eradication of polio program that has existed since 1988, for 2025, I think a realistic aim would be to have zero new cases for a year. It's very close. There are actually, a dozen or 20 new cases of wild type polio in the world per year in the last few years.

[00:03:48] Bernard: There are last pockets and hopefully, if the political situation in Afghanistan and Pakistan would stabilize just a little, this goal could be achieved.

[00:03:57] Angela: that's great. But this was a get to know you question, Werner. This is supposed to be about you.

[00:04:02] Bernard: I don't have any serious New Year resolutions .

But, conditions for skiing are fantastic this year, so I hope to get some. good skiing in, in the next few weeks, which would be a resolution. I'm retired so I can, allow myself some levity, I think.

[00:04:18] Angela: I think that's smart. So Kerrigan, how about you

[00:04:21] Kerrigan: thank you, Angela. So, I've, , ceased to have any, , New Year's resolutions, because I find they often short lived and, what I prefer to do is, Hope and, respond to what comes my way so that I live a meaningful life, and to take advantage of opportunities and directions that, allow me to transform situations into something that is meaningful.

a good example of that, was, a few years ago, I landed up, in a new division, my current Center for Vaccines and Immunology. and from the polio eradication program, we, branched into wastewater surveillance. And, has become something of, global interest and hopefully global significance, in time.

I love it. and I think, you're in very good company.

So here we are beginning of 2025 globalized world hopping from continent to continent. Quite easy now with many children who for the next few years will maybe not receive vaccinations. So let's start with polio. First off, Bernard, can you paint a picture for us of what the world was like when there wasn't polio vaccine, available and people around you, , people may have been getting this virus.

[00:05:34] Bernard: Well, I was born in 1946. Polio vaccination started in 1956. So I remember well that, for instance, swimming pools were closed in summer because of this scare of polio.

[00:05:47] Bernard: As a matter of fact, polio became a really important issue because of an increase in paralytic cases during the early 20th century. there was little talk about polio in the 19th century. And it is thought that, with better hygiene, infection was later, and, therefore, because polio is more virulent in older, children and young adults, the cases of prolific polio increased, reaching almost 100, 000 per year in the early 50s in the United States.

[00:06:19] Bernard: So these epidemics caused panic and, the, vaccine was eagerly awaited. we had a nanny. Of whom we, loved very much and, her child had polio, . so there was some personal, uh, Relation to polio and then I saw polio again in Africa when I was a fourth year medical student, there was an epidemic. There were some 10 or 15 cases in the hospital.

[00:06:43] Bernard: And also walking through the villages, you saw people probably had polio because they had this characteristic atrophy of a leg or so and were limping along. And of course, then there were these very famous cases like FDR. Who had polio, I think, although there was some second guessing, but from reading his biography, I think his case was quite typical.

[00:07:06] Angela: Just for full global audience of, young people . FDR stands for, Franklin Roosevelt. Very famous, polio victim. Yeah.

For present day people with, of polio, you can look to Itzhak Tehelman, who is A world famous violinist, and you can see when he hobbles onto the stage in YouTube how serious his, handicap really is.

[00:07:29] Bernard: So, polio is a very serious, when it touches the central nervous system. And, there was no controversy about vaccination when it appeared. It is almost 100 percent effective. It has almost eliminated polio, but as long as polio cases exist, the only way to protect people is by vaccination.

there is no drug, nothing you can do once it happens.

[00:07:54] Angela: Yeah, we will be getting to questions on treatment and management, really. let's start, though, from the very, very beginning. Can you give us a brief refresher on the virus itself, poliovirus?

[00:08:06] Bernard: poliovirus it's a picornavirus.

[00:08:10] Bernard: Picorno, pico, means small, and RNA means, well, ribonucleic acid. smallest pathogen, I think, that exists. It has only 7, 500 nucleotides. It has been completely synthesized in vitro, one of the first viruses where one was able to do so. a plus virus, meaning that when it gets into a cell, The nucleic acid that is liberated in the cell, functions as a messenger RNA and codes for ten proteins.

[00:08:40] Bernard: Among them, the proteins which determine the types of polio. There are three serotypes. the virus is an enterovirus, meaning it's in the gut. Symptoms are usually nonspecific. Some sore throat, diarrhea, a little fever. Most people it's asymptomatic. And then in a few percent, it goes on to cause an infection of the central nervous system, where it attacks the anterior horn cells, which control motricity.

[00:09:09] Bernard: And typically, The disease starts with a maximum effect, the paralysis becomes maximal within a few days and then recedes to a various degree. in a small minority of patients, the virus touches the brainstem, and this can lead to a respiratory paralysis. you probably have seen these iconic pictures of iron lungs, which were the only way , to sustain ventilation in the 1950s since, of course, replaced by intubation and, and all that.

[00:09:44] Bernard: so in that way, the disease can, be, fatal because of earth, respiratory paralysis, aspiration, pneumonia, et cetera. So that's in a nutshell what polio is.

[00:09:55] Angela: And so, for the sort of tropism, let's say, of this virus, what does it [00:10:00] need to get into a human cell?

Well, humans, for all practical purposes, are the only susceptible species.

[00:10:07] Bernard: They have this receptor, CD155, and therefore there are no animal models. it is a mystery why some people Get, neurological complications and the majority doesn't, are some speculations, maybe viremia in the beginning is more intense and symptoms are more intense, but I really people that knows why some get infected or not get neurological complications or not.

[00:10:34] Angela: Yeah. And so most people, like you said, are asymptomatic. How many in percentages? What would you say? Well,

[00:10:40] Bernard: of course, because symptoms are so non specific, who knows? But, at least three quarters are completely asymptomatic and another 20% may have minor symptoms of a viral infection, and then the rest will get some neurological involvement.

[00:10:56] Angela: And this may be why you could, , sustain an anti vaccine argument, because the majority of people really are fine with a polio infection and will be for the rest of their lives, correct?

[00:11:08] Bernard: Well, I mean, if you look at what the arguments, of the anti vaxxers are, There are three different strands of argumentation.

[00:11:18] Bernard: One is the mercury thing. Mercury, used to be a preservative in vaccines. It's no longer used. some people think that is related to autism and other, problems. The link, has been debunked for a long time. and anyway, there is no more mercury in vaccines. The link to autism has been claimed for many different vaccines. It is non existent. And then there is a specific problem to polio. There are two vaccines. One is a attenuated, but viable strain. the living vaccine has many, advantages. It is very cheap. doesn't need a sophisticated cold chain and it is infective in itself.

So if you have a vaccination campaign and let's say you reach 60 percent of susceptible people that should be vaccinated, they will excrete the virus in their, feces. And where the sanitary, situation is precarious, they will infect other people with the vaccine strain.

[00:12:21] Bernard: So, the vaccine spreads, that's a big advantage. But, it has a disadvantage, in very rare cases, the virus may become virulent. Virulent for the patient who gets vaccinated, that's one in a million or so. he will get paralyzed. He will get neuropolio himself or herself. And that can also happen in people who get the oral vaccine through infection.

[00:12:50] Bernard: That's why the oral vaccine in Europe and the United States has been abandoned for about 20 years. It is still used in developing countries and is still endorsed by the WHO because of its great effectiveness. cheap, price and, other advantages. So, that could be an argument against the oral vaccine, but the oral vaccine is no longer used in Europe and the United States.

[00:13:16] Bernard: So, that, also is not a valid argument against polio vaccines. .

[00:13:21] Angela: Yeah. Yeah. Fair enough. if we were to do like a mini review, we covered the virus itself. What about clinical presentation? We already covered that. established that most people are going to be completely asymptomatic, but those who are symptomatic, how do they present?

[00:13:37] Angela: what can a doctor who's never seen this virus, expect? What should we be looking for, to make the diagnosis clinically?

[00:13:44] Bernard: many patients, have pain in their legs, cramps and pains in their muscles. the patient that I saw in 1980 was typical. This was a man who was Infected by a vaccine related strain.

[00:13:57] Bernard: He was himself, of course, not vaccinated. Otherwise, he would have been immune. And he had pains and cramps in his legs in the morning, and then he had big lunch and went to sleep thereafter. And when he tried to get up, his leg just gave out under him and he fell to the floor with a pain in his leg. So that would be a very typical story.

[00:14:19] Bernard: then what is typical also is that the paralysis rapidly progresses within a day or two. It is maximum. And then it recedes slowly as the immune response kicks in.

[00:14:31] Angela: So this man actually was already in the neurologic phase when he was diagnosed with his polio. When was he actually infected?

what does the initial infection look like in those few who are symptomatic? It's an enterovirus. Well, it

[00:14:46] Bernard: is completely nonspecific. There are people, they will complain of fatigue or a little fever, diarrhea, a sore throat, but in most cases you cannot diagnose a polio infection and distinguish from any other enterovirus or other virus, in the population.

[00:15:05] Bernard: I guess within an epidemic, you would maybe have a higher index of suspicion and could diagnose the pre neurological infection by cultivating the virus from feces, but that's not a practical proposition for isolated rare cases.

[00:15:24] Angela: So I

[00:15:24] Bernard: guess if you saw a case now. Which is very unlikely. The first thing you would think is it something else.

[00:15:31] Bernard: But if there was a case, you would probably detect it only during the neurological

Yeah, because that's when it gets more specific. And , what was the lag time between that initial infection and the neurologic phase? Yes.

[00:15:46] Bernard: Well, from what I read, this is a few days to a week or two, but because most patients present with a neurological phase and you don't realize it before, I don't know whether it's very interesting to speculate on that because you don't diagnose it before and in any case, it's a few days.

[00:16:04] Angela: have there not been some rare cases where there was a neurologic phase like many months, even years later,

[00:16:12] Bernard: Well, I don't think so. there is the post polio syndrome, which is something different. This is in survivors of polio, they have deficits, they adjust to these deficits for 10, 20, 30, 50 years.

[00:16:27] Bernard: And then, suddenly in the affected leg, the remaining strength decreases. And, it decreases, , at various speeds, I read that it was something like 1 percent per year on the average in strength. Periods of, remission. this, because this is motor neuron disease. this is of course very alarming because you start thinking of ALS Amyotrophic Lateral Sclerosis, which is a devastating, always fatal disease.

[00:16:57] Bernard: It's not the same. It is a decrease in strength. And of course with the handicap, which is already there, and people are old, their general muscle strength decreases. it can be a serious problem. But that is very different from acute polio.

[00:17:14] Angela: Can post polio syndrome happen in any part of the body, maybe a part that wasn't clinically affected, in the neurologic phase earlier?

[00:17:22] Bernard: Well, I, think it mostly affects the, parts of the body that were initially involved when the neurological polio declared itself.

[00:17:32] Angela: So then what's happening? Does that mean the virus is still there? It's been latent? What's going on?

[00:17:38] Bernard: well, there are theories that of course, during the recuperation, the same motor neurons, which innervate a muscle group, sort of take over the work of other motor neurons. And instead of innervating, ten muscle fibers, they innervate a few hundreds. And in the long run, this sort of exhausts the neurons.

[00:18:01] Bernard: I don't have a very scientific explanation, but that's, what you can read .

is there any evidence that there's virus that's persisting all these years?

[00:18:10] Angela: I don't think so.

[00:18:11] Angela: Interesting.

the antibodies are neutralizing and they, go on, and the virus is eliminated.

[00:18:18] Bernard: Now, I would say that the very persistent protection, which exists in polio and, measles, for instance, makes you, think that maybe there is some antigen somewhere in the body, which. Keeps the immune response active, but I don't think that has been proved

[00:18:37] Bernard: for polio.

[00:18:39] Angela: .

[00:18:39] Angela: Have there been cases of, with polio in someone who already had one infection with polio, or is it almost never?

[00:18:46] Bernard: Well, yes. are, of course, these three serotypes. And when you're infected with a natural poliovirus, you have antibodies against type 1, if you are infected with type 1,

[00:18:58] Bernard: and

[00:18:58] Bernard: there have been proven cases of infection with the other types after a natural infection.

[00:19:04] Angela: So antibodies are quite specific.

They are half specific, at least, yes.

[00:19:09] Angela: Do we know, by the way, what the correlate of protection is? Is it antibodies?

[00:19:14] Bernard: Yeah, I think this is a case of neutralizing antibodies that are. effective at least after vaccination. That's what it is.

[00:19:22] Angela: coming back to, the basics, , somebody who's, potentially going to be faced with polio infections. how do you diagnose polio virus today?

[00:19:30] Bernard: Well, you isolate the virus from feces. And then you want to sequence it, because what you need to do is to distinguish natural polio from vaccine related polio.

[00:19:43] Bernard: this used to be by oligotyping, which is a sort of a complicated two dimensional electrophoresis. That's no longer done. Now, because sequencing and reverse transcription is so easy, that's what you would want to do. And that's also how polioviruses [00:20:00] in, wastewater are, discovered and seen.

[00:20:03] Angela: Kerrigan, any words there from your side? in terms of wastewater surveillance?

[00:20:09] Kerrigan: Well, I can add something around the diagnostics. our country, and, institution is the polio reference laboratory, for the, region. we have, of course, an active surveillance program for acute flaccid paralysis.

[00:20:23] Kerrigan: so polio of course presents with a sudden onset as, explained. But the differential diagnosis is, broader than polio. There are a number of other conditions that present in a similar way. The key thing is to conduct the laboratory diagnostics in anyone meeting the case definition.

[00:20:38] Kerrigan: So in our surveillance team we have, a whole, lot of surveillance officers who are usually nurses who, work closely with clinicians to identify cases of acute flaccid paralysis. And following these cases, stool is submitted, for culture. This is one of the challenges of the polio elimination program is that culture is time consuming and requires a very sophisticated laboratory environment.

[00:21:02] Kerrigan: One has to have self culture facilities and then to inoculate stool samples into the cell culture and then to be able to have the technological expertise to detect a cytopathic effect that is a sort of a clumping of the cells when the poliovirus is present. And then of course there's a double culture process where, we first inoculate, non specific cells and then if it looks like there's a poliovirus present, then we, inoculate cells that, are modified to have that CD155 receptor, or CD150 receptor that then, will these cells will only be infected if polio is present.

[00:21:38] Kerrigan: and thereafter we go and do sequencing and that whole process can take two weeks, before you can get a negative result. if there's a positive result with a positive cytopathic effect usually occurs within three to four days. And the process, perhaps can be completed in seven to ten days, where you have a positive virus, cell culture, and then you need to sequence it.

[00:21:59] Kerrigan: And this means that the turnaround time for identifying cases of polio is very long. And, we also have to factor in that these specimens are sent to us from a number of African countries,. And, and so then it becomes very difficult to respond meaningfully, to outbreaks.

[00:22:15] Kerrigan: one of the, new areas for research, which has sadly taken a rather longer time than in other communicable diseases, is the development of direct PCR testing, where we test stool for, polio. and this takes a while, in terms of rolling it out within the global, polio eradication.

[00:22:33] Kerrigan: program. unfortunately it is less sensitive than culture, which is, the gold standard. So, you know, even if we do add in, direct PCR testing, we're going to miss a few cases. your question about wastewater is interesting. so environmental surveillance has a lovely history, with regard to polio.

[00:22:51] Kerrigan: It was noticed in the, polio outbreaks in Scandinavia. in I think the 70s and 80s of the last century that, in towns that had polio, epidemics, were testing positive for poliovirus. Of course, the virus is a very hardy virus. It doesn't have a cell envelope. And so it's able to survive, in the environment and even remain infectious for a long time.

[00:23:17] Kerrigan: The association between environmental contamination during an outbreak was initially sort of of interest value and then it was realized that because of the very low symptomatic ratio in polio that If you have large numbers of people, the volume or the, burden of disease is more likely to be reflected in the environment than it is in, symptomatic cases.

[00:23:43] Kerrigan: And so, People started, testing wastewater, and eventually the evidence was overwhelming and the WHO incorporated environmental surveillance for polio into the Global Polio Eradication Program. what we've seen in our reference laboratory here is where we do testing both of stools, in cases with suspected polio, in other words, acute flaccid paralysis, And we do, environmental culture that we often find, neighboring countries that have, polio, neurovirulent viruses in their wastewater, but they haven't detected, clinical cases of acute flaccid paralysis.

this is fascinating. are you saying these are wild type viruses? These are not vaccine related viruses.

These are vaccine

[00:24:28] Kerrigan: related viruses. So, , at the moment, and, I don't want to jump the gun. Your question is where's polio, wild polio endemic in the world, Bernard mentioned that, wild polio is endemic in Afghanistan and Pakistan at the moment only. in, 2000. 21, there was a case of wild polio identified in Malawi, and Mozambique in the area, cross border migrants, between the two countries.

[00:24:53] Kerrigan: And, genetic, sequencing identified that this virus had an origin about 18 months prior in Pakistan. the continent did not lose its polio free status because it was deemed to be an imported case and there was a robust, outbreak response, with, vaccination and, the wild polio virus type one hasn't been detected, in the region subsequently.

[00:25:19] Kerrigan: But obviously this has been a very busy time for our. laboratory. I can go back to the wastewater, surveillance. So in our country, South Africa, we do wastewater samples for polio. We, process them for polio for a number of countries. And two countries on our border, Botswana and, Zimbabwe, have both had vaccine derived poliovirus this is VDPV2, vaccine derived poliovirus type 2, in their wastewater over the past 24 months, they have not had clinical cases of, polio due to these same viruses at this stage.

[00:25:56] Kerrigan: Now, the reason for this is likely twofold, The first is the low, symptomatic to asymptomatic ratio. So, about 98 to 99 percent of persons with polio infection will be asymptomatic, and only 1 percent will develop symptoms of paralysis. If one's clinical surveillance program is weak, These few cases may go undetected.

[00:26:22] Kerrigan: So it's highly likely that an individual with paralysis will be taken by their caregiver to hospital, but the clinician might not submit samples for surveillance testing and diagnostic testing, and we will likely miss them. The second reason is that in individuals, and this is less likely in the African continent, in individuals who've been vaccinated with the inactivated polio vaccine that

[00:26:48] Kerrigan: bernard was talking about, these individuals may still be infected. with the live poliovirus because the inactivated poliovirus only induces an immune response in the blood. It does not induce a very strong immune response in the gut and so what it means is that the initial ingestion of a wild poliovirus or vaccine poliovirus in someone who's been vaccinated with inactivated poliovirus will still lead to an infection of the enterocytes.

[00:27:20] Kerrigan: the cells lining the gut. However, that infection will not progress to the viremic stage and then infect the anterior horn cells. So the infection remains localized in the gut. what that means is that they may still pass the infection onto other people. So that means that the wastewater will still be contaminated with the poliovirus, and if the population has good vaccination coverage with IPV, there will be no cases of acute flaccid paralysis.

IPV being inactivated polio, so the killed,

[00:27:58] Kerrigan: polio vaccine, correct?

[00:28:00] Angela: Yes,

[00:28:00] Kerrigan: correct. So there was a very interesting and tragic case of polio in New York State. This passed two, three years ago, where 23 year old male was, part of a religious community that declined vaccination and he had not been vaccinated against polio at all.

In the States. the vaccination that's made available is only the inactivated polio vaccine. he came down with paralysis and eventually a diagnosis of polio was made. And the puzzling thing was why there were no other cases of polio. And so because of the SARS CoV 2 wastewater surveillance program, there were wastewater samples that had been collected throughout the state.

[00:28:40] Kerrigan: the teams went back to those wastewater samples and then also prospectively continued to look for polio. And they found them in a very widespread distribution in the state. And the reason for this most likely was that the vaccine derived polio virus, that had infected this young man had been imported many, uh, months before.

[00:29:02] Kerrigan: But because the population had been well vaccinated with this inactivated polio vaccine, infection with this polio virus was still possible. individuals were becoming infected but were at no risk of developing polio disease, but they were passing it on to other people. And this was evidenced through the wastewater testing.

[00:29:24] Kerrigan: So I suppose I'm telling you that story two reasons. the first is the importance of vaccination coverage with polio vaccine, whether it be the inactivated polio vaccine that is recommended by the WHO and used by most countries, in the world, or, the oral polio vaccine, which is a live attenuated polio vaccine, which is used in the African for, reasons that Bernard explained.

[00:29:49] Angela: Wow. I did not know about this New York case. You said it had been introduced a few months before. Could it be traced back?

[00:29:56] Angela: What was its lineage?

[00:29:58] Kerrigan: There is [00:30:00] excellent polio molecular surveillance being done across the world. In a single center that's being the, Center for Disease Control in Atlanta.

[00:30:09] Kerrigan: And unfortunately, that information is not publicly available, unlike during the SARS CoV 2 pandemic when, the genotyping and lineage of all strains were widely available. And this is something that the global community can really, put pressure on, the, Global Polio Elimination Initiative, the GPEI, is for the opening of these resources, and knowledge, so I'm sure that the answer is known and the case was, very well described in the MMWR, that's the publication of the, Center for Disease Control.

What I can say that the, sequencing data is shared with the global polio reference laboratory. So, the wild polio case that was, identified in Malawi in 2021. was shown to be an orphan virus. So, the molecular clock of poliovirus is very interesting.

[00:31:00] Kerrigan: It undergoes a, one molecular nucleotide change every six weeks, assuming replication in a human host. and this allows us to, to look at, very crudely, the length of time that a particular virus has been circulating relative to other viruses that have similar sequences. And what we are able to identify chains of transmission.

[00:31:31] Kerrigan: So you can sequence your polioviruses, whether they're vaccine derived or ordinary polioviruses, and determine how related they are to each other. And this allows us to then say, , this is the most closely related strain to that. we can also tell how long that virus has been circulating in the population.

[00:31:52] Kerrigan: undetected. what we identified in the wild polio, uh, Malawi was that the virus had been circulating for 18 months without detection, on the African continent or in Pakistan. Usually, when there's good surveillance, you can see, immediate, chains of transmission. So, you can see single nucleotide changes emerging from strain to strain.

[00:32:17] Kerrigan: and there's a, good linear or temporal relationship between the identification of one strain and another. the long gap between the wild polio strain in Malawi and the one in Pakistan was likely due to COVID. So during the COVID pandemic all the polio surveillance staff were allocated to SARS CoV 2 vaccination or surveillance programs and the detection rates and the surveillance indicators for polio declined terribly.

What we remain unsure of is whether the virus had been circulating in Pakistan and was a, imported case, or whether it had traveled down the east coast of Africa. with, the, ongoing trade and travel there is between, Pakistan , and the east coast of Africa.

[00:33:05] Angela: Sorry, because you can't determine which, is that why you call it an orphan virus?

[00:33:10] Kerrigan: That's exactly, yeah. So the New York case, I'm sure it was possible to determine the lineage of that case and where it had originated from in the world, but, there was obviously a big gap in surveillance because, the wastewater program in the United States at the time wasn't, particularly focused on looking for poliovirus.

[00:33:30] Angela: This is fascinating. we will be coming back to wastewater surveillance when we discuss rubella as well. coming back to you, Bernard, just a couple of questions on management. first of all, is there any treatment for this initial phase of gastrointestinal polio.

[00:33:46] Angela: And how is poliomyelitis treated? , , how do we deal with the neurologic phase?

[00:33:51] Bernard: There is no specific treatment for the virus. And of course, because you can't really diagnose the gastrointestinal phase. Even basic identification, as we just heard, too laborious to be able to treat in time.

[00:34:06] Bernard: But there are no drugs available, so let's just forget about drugs against the virus itself. Now, once paralysis sets in, there are all these other measures, physiotherapy and then the prosthesis, for instance, against the falling foot, which is of polio, so that people can walk more or less normally.

[00:34:29] Bernard: big attention is paid to the knee, instance, , if the knee joint is stabilized, that can be surgically or again by prosthesis, etc. These are the methods that are important access,. of course, To public facilities and all that, but these are not medical measures in the strict sense of the word.

[00:34:49] Angela: So now, , looking at, transmission, Kerrigan, , polio virus is transmitted by the fecal oral route. as far as we know, how long can an infected person be infectious? and besides shedding the virus in stools, is the virus found in any other bodily specimens?

[00:35:06] Kerrigan: So there've been some lovely challenge experiments where individuals have been infected with the oral polio vaccine. And because the oral polio vaccine is a live attenuated vaccine and it's closely related to the virus itself, it's possible to mimic natural infection with a harmless strain of polio, that being the vaccine strain, and then understand these very important questions such as how long is someone infectious for and how long do people shed the virus.

[00:35:42] Kerrigan: Obviously, when looking from an epidemiological perspective, we want to understand these, facets of polio infection so that we can make and give good advice around infection prevention and control. So these challenging, experiments have shown that, an individual excretes polio virus for two to four weeks after infection and that if an individual has a robust immune system, which most people do, their, cell mediated and, humoral immunity, in other words, the parts of the immune system that adapt to deal with intracellular infections and extracellular infections will sterilize the infected cells so that they cannot produce the polio virus, any longer within two to four weeks.

[00:36:33] Kerrigan: it can be as long as six weeks. this means that, it's, possible for the individual to transmit infection with polio virus after they've been infected. As I shared with you, the different kinds of vaccinations, so the inactivated polio vaccine has a different immune response to the oral polio vaccine and this leads to differential protection against a challenge.

[00:37:04] Kerrigan: So if an individual has been, vaccinated with inactivated polio vaccine, their humeral immunity or their antibody immunity in the blood is very strong. whereas if an individual has been vaccinated with oral polio vaccine, their humeral immunity and their gut immunity is very strong. This means that, a challenge with, a re challenge with, a vaccine strain, in other words an inocular strain, will not lead to infection and the individual won't be able to pass on the virus.

[00:37:37] Kerrigan: So, um, Oral polio vaccine is advantageous for a number of reasons. The first is that when an individual has never been vaccinated against polio or infected with polio, is vaccinated with oral polio vaccine, that oral polio vaccine is a live attenuated vaccine, a virus, and it will cause an infection in their gut.

[00:37:58] Kerrigan: And they'll pass this virus strain onward and any other children in the area who have not been vaccinated will be infected with that vaccine strain and will develop immunity to that vaccine strain. So, not only is that child being vaccinated, they're also vaccinating other children around them. if, they will not be able to be infected with, oral polio, virus again because their gut immunity is strong.

[00:38:26] Kerrigan: So this means that this, oral polio vaccine is very, advantageous in terms of global polio elimination. If an individual has been vaccinated with inactivated polio vaccine, If they ever come across wild poliovaccine or vaccine derived poliovirus or wild poliovirus itself, they can be infected and pass that infection on, but they definitely will not get paralytic polio themselves.

[00:38:52] Angela: Truly

[00:38:53] Angela: invasive

[00:38:54] Angela: infection. just to follow up on that, has the virus been found in any other bodily compartments besides stool? Well,

[00:39:02] Kerrigan: There is a short viremic phase, as there is with all virus infections. So there's replication at the site of infection, followed by a viremia. But, diagnostic testing does not focus on that viremic period.

[00:39:14] Kerrigan: It's usually quite short. The virus lodges in the neurological tissues. it's also possible to detect the virus in, CSF, so cerebrospinal fluid. , it's a neurotropic virus. So, , we've had some cases, in South Africa of, immune deficient, vaccine derived poliovirus.

[00:39:35] Kerrigan: And this is a very interesting condition. When oral polio vaccine is given at birth, as it is in South Africa and many countries on the continent, most children, and in fact only one in 400, 000 children have an inherited disorder of immunity. It assumes that most people are immune and they will, sterilize, the natural infection with this vaccine virus.

[00:39:56] Kerrigan: However, if a child has an inherited disorder [00:40:00] of immunity. They, and particularly those that relate to the child's ability to produce antibodies, so the B cell immune deficiencies, they're not able to sterilize the infection. , this vaccine strain. Lodges in the gut. And it replicates and replicates and replicates in an ongoing way.

[00:40:23] Kerrigan: And that would be okay, except that, the replication of this vaccine leads to naturally occurring errors in transcription of the virus from one generation to the next. when there is between 11 and 18 percent, nucleotide difference, between the original vaccine strain and the, progeny, the, subsequent viral strains after many months of replication, this virus.

[00:40:53] Kerrigan: can revert back to virulence. And this is where we observe the phenomenon of a vaccine derived poliovirus. When this vaccine reverts back to virulence, this child Can develop paralysis. And so, in the time period that I've been, aware of this in South Africa since the early two thousands, we've had three cases of vaccine derived poliovirus in children with inherited, disorders of immunity.

[00:41:20] Kerrigan: Now, in some of these children, we've been able to detect the poliovirus in CSF, these children have had lumbar punctures and we are able to do PCR and detect it, and in fact, even sequence the virus.

[00:41:31] Angela: that's, certainly a reminder that vaccines, are not perfect and, are not without, potential side effects. Obviously they need to be used carefully, no medication, no, intervention is perfect and without side effects. in terms of transmission, do we know the actual R naught of polio?

[00:41:52] Angela: And will this R naught that we think we know, if we do, will wastewater surveillance?

So, the basic reproductive number in layperson's terms is the number of secondary infections that will happen when, an individual who is infected, finds themselves in, a population that hasn't been exposed to the virus. The effective reproductive number then is When an individual, who has the infection, finds themselves in a population that has variable levels of immunity. So, the basic reproductive number of polio, is probably not known, but can be estimated to be around, 18 to 24.

[00:42:33] Kerrigan: It's incredibly high. what that means is that a single case, individual with polio may lead to 18 to 24 secondary cases of polio. Now because the asymptomatic to symptomatic ratio is such that there are very few symptomatic cases of polio, , the infections, the onwardly transmitted infections won't all manifest as paralysis.

only, um, 1 percent of infections will show paralysis. when we consider this scenario where an individual with polio infection, lands up in a community where there's been variable vaccination, the effective reproductive number can, ranged from 3 to about 12. one of the reasons for the long and large, effective and basic reproductive number of polio is The fact that the virus is very hardy in the environment, so it can survive on surfaces, dryness, changes in pH.

influenza, by comparison, has an effective reproductive number of three. so for every single case of influenza, there'll be about three secondary cases. Has a variable effective reproductive number because of the context in which an individual finds themselves. So higher socioeconomic and more affluent communities, tend to experience polio outbreaks with lower reproductive numbers because of hand washing and, good sanitation that decreases the number of opportunities that, an infected person may have to transmit the virus onwards.

[00:44:07] Kerrigan: This has been, quite a challenge for us to figure out the effective reproductive number of polio in different contexts because the literature is very, broad, and one never knows where polio may land up, whether, as we see, it may land up in New York State, or, in South Africa, or in the favelas of Brazil, , so there's quite a large variation.

[00:44:28] Angela: Very, very interesting. Berna, coming back to you, let's say we have a case of polio, a new case, what should we do, in terms of infection prevention, transmission prevention? what are the measures that need to be taken?

[00:44:44] Bernard: Well, as we said several times already, much depends on the context. In a population with a high vaccination coverage, there is nothing to fear from an individual case. There will be no epidemic and there will be no spread and no secondary of neurological polio.

[00:45:03] Bernard: gov I think the most important thing that would be the time to boost vaccination and to remind people that without vaccination, there is no absolute protection against serious diseases like polio. the difficulty, as we heard, is the delay in diagnosis the fact that there are so many asymptomatic or post symptomatic cases.

[00:45:26] Bernard: So, to limit the spread, you would have to, accommodate a lot of people with sanitary measures that are unlikely to have any concrete effect on further neurological cases, which is really the important thing. But I think the most important lesson is, This would show that you need to vaccinate and continue to vaccinate.

[00:45:47] Bernard: That would be the message that we should give the public if such a case should occur.

[00:45:53] Angela: Yeah, as you say, don't let a crisis go to waste. A good crisis should be, should be fully used to the good. Thanks a lot. let's turn now fully to rubella. that is a disease that really, I think, very few physicians have actually had to manage.

[00:46:10] Angela: And you in South Africa, Kerrigan, are in the middle of an epidemic, an outbreak of rubella. Can you describe to us a little bit, what that's like? what are you seeing? Tell us a little bit about rubella disease.

[00:46:23] Kerrigan: it's been an interesting time in South Africa. We are one of the few countries in the world, I think there are now 20 countries out of 198, I think, that have not implemented the rubella vaccine. most countries use measles mumps rubella vaccine, the MMR,

south Africa, for various good reasons, has been very slow to adopt the use of either the MMR vaccine or the combined measles rubella vaccine. And just some background to that is that we had a terrible TBHIV pandemic, over the last 20 years. And, we also had advocates of various other vaccines, the pneumococcal conjugate vaccine, the, human papillomavirus vaccine, that were deemed to have far greater public health consequences.

[00:47:10] Kerrigan: In our context than The public health problems associated with rubella. the other reason is that we are not a Gavi funded country. So the Global Alliance for Vaccines Initiative, Gavi, supports low and middle income countries to introduce vaccines by adopting firstly a sponsored and then a transition program to self funding.

[00:47:31] Kerrigan: And Gavi has right from the outset used the combined measles rubella vaccine. So we have been using measles vaccine alone and not combining it with rubella vaccine. This year our department of health made a decision to introduce the rubella vaccine but it has been something that has been discussed and debated at length.

[00:47:52] Kerrigan: part of the problem is that, The introduction of rubella vaccine has to be conducted, with sustained high vaccination coverage for a number of years, in fact, in perpetuity, otherwise one lands up, not doing as well as nature in vaccinating or rendering the population immune. So what we've observed in South Africa, to date is a seasonal rubella Classically, in our surveillance programs, we see rubella peak every year from, around about August, September to November, and that's the southern hemisphere spring to summer.

[00:48:26] Kerrigan: it's quite curious as to why this happens. I mean, all diseases sort of have seasonal predilections. we see influenza during the winter and rotavirus that causes diarrhea during the winter. Rubella classically occurs in spring. The National Institute for Communicable Diseases, where I work, runs a fever rash surveillance program, and all persons across our country, which has around 60 million people in it, who present to the healthcare system with fever and rash, the clinician is requested to submit a throat swab and a blood sample for Both measles and rubella testing and so we've been able to document, the seasonal, phenomenon of rubella for a number of years.

[00:49:05] Kerrigan: Now what happened, during COVID, interestingly enough, is That, our country, like, all the countries in the world, adopted various measures of severe lockdown and other non pharmaceutical interventions, such as mask wearing and social distancing. rubella is transmitted in the same way as measles, with a, person to person transmission.

[00:49:24] Kerrigan: It's a respiratory transmitted infection. And it very low effective reproductive number, it ranges from about three to about seven. , the basic reproductive number is probably in the order of 12. It's a little higher, 11 to 12. But, having said that, in practice, the effective reproductive number is closer to 3 or 4 or 5. so it's probably as infectious as influenza. virus, but it's much less infectious than the delta or the omicron strain of SARS CoV 2, which was around 8 to 10.

[00:49:57] Kerrigan: so what happened during the SARS CoV 2 [00:50:00] pandemic was the non pharmaceutical interventions effectively shut down the transmission of rubella. Which is wonderful, but in the long term unsustainable. There have been some serological studies by a number of different groups using residual sera, and looking at the sera prevalence.

[00:50:17] Kerrigan: Of rubella in pregnant women, given that we don't have a vaccination program, and what we've shown is that around 95 to 98% and sometimes as high as 99% of pregnant women in South Africa are immune to rubella. And what is is that the seasonal rubella vaccinates effectively renders immune through infection.

[00:50:42] Kerrigan: Successive birth cohorts of. new children entering into the population who are by nature of life susceptible to rubella. so when the spring comes along, then there's a fever rash, little localized outbreak in the creche or in the school. progressively over the years, Young children up to the age of 15 become infected with rubella and then immune.

[00:51:09] Kerrigan: by the time women reach reproductive age, there are very few women who are vulnerable to rubella. and for this reason, or, and perhaps I need to go back to answer one of your questions, is rubella infection in children is very mild. in fact, the very name rubella means little.

[00:51:26] Kerrigan: rash, and it was named, in contradistinction to measles, which caused a florid maculopapular rash and a severe illness. Whereas rubella is a very mild infection in young children, and even in adults. It has incredibly few complications as an acute infection. very rarely children might develop low platelets.

[00:51:50] Kerrigan: some, adolescents, particularly females, develop an arthralgia and sometimes an arthritis. there are cases, about 1 in 3, 000 infections leads to a mild, encephalitis, which is usually self limited. So they'll get a very bad headache and if you do a lumbar puncture, you'll find, evidence of a viral picture on the cerebrospinal fluid viral infection. So, the point is that rubella in itself is not a public health problem, acute rubella. Where there is a problem is when this infection occurs in a woman who's in her first trimester of pregnancy, and she's not been infected with rubella virus or vaccinated.

[00:52:31] Kerrigan: in, in her life. there the virus itself has a predilection for neurological and cardiac and sensory neural tissue. it infects the placenta itself and then the virus, localizes in these cells that eventually in the organogenesis of a young developing fetus become the eyes, ears, and heart.

[00:52:52] Kerrigan: in these cells, it, Lands up, affecting the cell structure and affecting cell division and causing premature cell death. so these, children are often born with a triad of sensory neural deafness. congenital heart defects and blindness due to cataracts due to direct retinal damage.

[00:53:14] Kerrigan: this renders it a highly undesirable infection. It's a bit like Zika virus, in fact, which, also causes a very similar picture as an acute infection in adults, but, has teratogenic effects on the developing brain. Fetus.

there's no danger or elevated risk to the pregnant mother.

[00:53:31] Angela: It's entirely the fetus.

[00:53:33] Kerrigan: Correct. So I waylaid myself. I was telling you the story of why the South Africans experiencing this massive rubella outbreak. So what happened, is that in 2020, when we had this lockdown, and for the rest of 2021, when our population like across the world was very nervous about SARS CoV 2 and everyone was wearing masks and no one gathered together, big gatherings, there was no rebellion.

[00:53:58] Kerrigan: So there was no seasonal. And to give you an example, I think we used to detect in our feverish surveillance around. One and a half thousand to 3000 cases of rubella every year during 20 20, 20, 21, and 22. I think we had 17, 23 and 19 cases of rubella detected. So there was no rubella, literally.

[00:54:19] Kerrigan: of course you can appreciate then that children under the age of 10, at the start of 2020 and children who were born in twenty twenty, twenty twenty one and 2022, as well as 2023 had no exposure. And so then this year, when spring came along, oh my goodness, not only did we have the birth cohorts of children who, in prior years, under the age of 10, who hadn't had exposure to seasonal rubella, we had three whole years of, new children who were susceptible.

[00:54:49] Kerrigan: And so, just to give you an example, we've had around, Between 9, 000 cases of rubella detected in 2024 through our fever rash surveillance. Our laboratory in fact hasn't finished testing all the cases because we've been absolutely inundated. So what has given us some pause for relief is that when we've looked at the data from routine antenatal testing, which happens in patches across the country.

[00:55:18] Kerrigan: Persons of 20 years and older have had exposure, enough exposure in the past to have been immunized effectively against rubella through natural infection. And so the incidence in this outbreak of congenital rebellious syndrome most likely will be higher than our background, but it will not, and we pray, be devastating.

[00:55:41] Angela: Because

[00:55:41] Kerrigan: you

[00:55:42] Angela: don't expect too many teenage pregnancies,

[00:55:44] Kerrigan: is this way. Exactly. And that is where the risk comes in. And so unfortunately we do have, a large, social problem, teenage pregnancies in South Africa. When I say large, it's relative. we have a birth cohort of about 1. 1 million new births, live births every year.

[00:56:02] Kerrigan: And, under 10 percent of these are born to teenage pregnancies. So, there is a likelihood that we will see an increase in congenital rubella infection. But, the magnitude of it, we're not sure about at this stage. In our surveillance in the, nine to 11,000 cases that we've seen, over 98% of cases are occurring in children under the age of 15 years.

[00:56:26] Kerrigan: So, we have very few cases that are being reported to us, of infection in older age groups. However, the ratio of symptomatic to asymptomatic infection. So, unlike polio. Rubella cases are more apparent, but still there is about a third of rubella infections are asymptomatic.

[00:56:48] Kerrigan: So an individual may experience mild prodromal symptoms of a fever and sort of body achiness, but they may not develop a rash. Well, they may be entirely

[00:56:59] Angela: acid. Can you say how many people who will have a primary infection, how many will get a rash? How reliable is the rash of rubella?

[00:57:09] Kerrigan: Around 66 percent so two thirds of children and adults will get a rash.

[00:57:15] Kerrigan: The rash is a very fine, rash. Infection in a person with a darker skin, it might be undetectable. however, sometimes the rash doesn't appear. It is an immunologically mediated phenomenon, much like measles. So the rash appears, at the same time as, the appearance of, more or less, of IgM antibodies and, the cessation of, viremia or, viral secretion in the oral, saliva.

[00:57:42] Angela: So it does not correlate with the viremia phase, , you just said it starts when viremia ends. So let's do the whole timeline, you get infected on day one, let's say, how long is the incubation period? When do you start becoming symptomatic if you're in those two thirds?

[00:58:00] Angela: And then, okay. First symptoms you said are, you know, sort of non specific. And then when does the rash come? On which, day?

[00:58:07] Kerrigan: traditionally, we, use the time table of events that's used for measles infection. And so we count day nought or day one as the day of onset of rash. so I wanted to put that out there.

[00:58:20] Kerrigan: We, so we won't count day one as the day of infection. we'll count day one as the day of onset of rash. And the reason for this is that the, immunological, time course of infection, is very easy to correlate. when. you have a clinical history of rash onset, so it's a kind of a landmark feature that you can say, right, on this day, rash appeared, therefore, working backwards, this is what was happening and working forwards, this is what's happening.

[00:58:45] Kerrigan: So, classically, the incubation period for rubella is, longer than measles, it's around 14 to 21 days. an individual will start secreting virus from the oropharyngeal, secretions slightly after the remic phases started, which is about seven days before the onset of rash. obviously no cases identical and there's some leeway, but.

[00:59:10] Kerrigan: it's recognized that the period of infectiousness can start as early as seven days before the onset of rash. And then the period of infectiousness ends between four to seven days

[00:59:21] Angela: after the onset

[00:59:22] Kerrigan: of rash.

[00:59:24] Angela: After the onset. So even if the rash is still there, because it's an immune phenomenon.

[00:59:29] Kerrigan: Correct.

[00:59:29] Kerrigan: So, when we talk about minus seven days, the way the graphs, are constructed is the vertical axis, shows the proportion of people with a positive test So for example, a PCR test of the saliva will show whether the virus is excreted. a test for IgM antibodies in the blood, will show when the IgM antibodies appear.

[00:59:52] Kerrigan: A PCR test in the blood will show When the virus is present in the blood and the graphs will show the proportion of people, the [01:00:00] proportion of cases that have a positive PCR test on day minus seven or on day naught. the graph shows a lovely curve. a bell shaped curve, reflecting the sort of range of positive to negative results.

[01:00:13] Kerrigan: So, the infectiousness of, rubella can surely be over between four to seven days after the onset of rash. At that point one can be assured that the vast majority of individuals who have rubella are non infectious. one of the challenges with rubella is containing the virus. So Bernard was talking about the measures to contain polio.

[01:00:36] Kerrigan: cases. If an individual has polio and everyone around them is vaccinated, there's really no need for, containment measures. however, in, rubella in our context, there were, with this large outbreak and we don't have a rubella vaccination program, there were lots of questions around, you know, should we close schools?

[01:00:55] Kerrigan: should someone stay at home? what should we do? We've learned a lot from the COVID pandemic. Closing schools is a majorly disruptive thing. not only, in terms of the practical logistics of who's going to look after the kids if they're not at school, but the educational impact is terrible.

[01:01:12] Kerrigan: One of the problems is that one third of people with rebellion infection are asymptomatic. And the second problem is that when the rash appears, that person has been infecting other people for a period of up to seven days prior to the rash onset. So we've advised our communities not to close schools and that, um.

[01:01:31] Kerrigan: Even, quarantine or, isolation rather of children with infection is probably not necessary. in the sense that the consequences of infection amongst children are minor and that the vast majority of the adult population is immune we've advised really parents and caregivers to manage their children symptomatically.

[01:01:53] Kerrigan: If the child has a high fever and they're not feeling well, let them stay at home. But from a public health perspective, we have not issued any guidance to contain the infection, through isolation and school closure.

[01:02:07] Angela: It sounds perfectly logical. and when you do shut things down, there are perhaps ramifications downstream with other organisms.

[01:02:16] Angela: surprises that by definition can't be foreseen, years beforehand. some last housekeeping things, What does that rash look like? Is it maculopapular? What parts of the body are affected? If you have darker skin patients, can you use palms, soles of feet, or does it not,

[01:02:33] Kerrigan: Basically, the rash, starts, in the upper body, the face and the neck, and then progresses downwards. It is macular papula, it's not as, prominent or as clearly visible. demarcated as measles rash is. It doesn't occur on the palms and soles, so one can't look at these as a guide.

[01:02:51] Kerrigan: It doesn't cause coplix spots as we see with measles, but even then, spots are not helpful. So there are a number of causes of macular papillary rash, there's a differential diagnosis and this includes, obviously measles, but then things like parvovirus B19, other coxsackie or echoviruses, the exanthem subitum or HHV6 and HHV7 can also cause very similar rash to this one.

[01:03:17] Angela: what kind of virus is rubella virus? Does it have a non human reservoir? just the basics on that.

[01:03:24] Kerrigan: Yes, the rubella virus does not have a non human reservoir, which means that it exclusively infects humans.

[01:03:32] Kerrigan: And this is one of the reasons why, it's been targeted with measles for elimination. it has several advantages that render it very easy to eliminate. The first is, that it has no non human reservoir. The second is that it's a very stable virus. There is only one. serotype. And even if they are genetic, variation or genotypes, which they are, they don't lead to changes in antigenic structure.

[01:03:57] Kerrigan: So the virus, unlike SARS CoV 2, doesn't mutate and have variants. there's a very inexpensive and incredibly safe vaccine that is highly immunogenic. the vaccine is a live attenuated vaccine, but it doesn't have any, changes in nucleotide sequence when it causes infection. So, it's unlike the poliovirus.

[01:04:18] Kerrigan: It carries no risk, for onward transmission. because it may be combined with measles vaccine, there are, mutual benefits. we can eliminate, and eradicate two diseases with one program. it has been targeted by the World Health Organization for elimination along with measles, which would be a wonderful thing.

[01:04:38] Angela: just following up on your observation that there is only one serotype of rubella. does that mean that when you get infected with natural rubella, once you've been infected once,

[01:04:49] Angela: do we think that you have lifelong immunity?

[01:04:51] Kerrigan: So, rubella is what we call an immunizing infection. it, elicits immunity that protects from subsequent infections due to rubella, and usually that lasts for the rest of one's life. it has been noted that there may be a decline in antibody titers in older persons, but it's suspected that, these antibodies are present but just undetectable levels and that re exposure occur, there will be a boosting effect.

[01:05:16] Kerrigan: So, subsequent infection with rubella virus is incredibly rare. It has been documented, but it's very, very rare.

[01:05:22] Angela: So the rubella vaccine is, as you say, it's particularly safe. Are you aware of any anti vax sentiment that is directed specifically at the rubella vaccine? Or is there rather a case of Collateral damage after all of the misinformation trying to link the measles vaccine to autism. And because it's usually given with the measles, is it just collaterally lost?

We were aware during SARS CoV 2 of a, growing and emerging anti vaccination sentiment, in South Africa. and we anticipate that there will be residual, fallout for the vaccine. one of the advantages perhaps in our context is that, the rubella vaccine will be given with the measles vaccine, and, there's no objective change in our expanded program of immunization.

. so, we are monitoring, the anti vax sentiment through a number of initiatives conducted in the South African Medical Research Council and in, work that is being done by the South African Vaccines Initiative, and we'll keep tabs on the impact over time.

We are now coming to a close. Bernhard and Kerrigan, what are the key messages you'd like to leave our listeners with? Bernhard, you first.

[01:06:34] Bernard: Well, , regarding polio, this is a disease that's close to eradication.

[01:06:39] Bernard: There is no treatment, so the only way to protect is vaccination, and as long as wild type polio circulates, and as long as the live oral polio vaccine is in use in the world, the only way to protect the population is by a high vaccination coverage.

[01:06:57] Angela: Thank you. Kerrigan, any last words?

Similar to Bernard. vaccination is Incredibly safe and the benefits of vaccination are something that extend not only to our little one's lives but to the lives of our community, population and the world. A disease somewhere is a disease everywhere. Polio in Afghanistan and Pakistan could mean polio in South Africa tomorrow.

the only way we can make ourselves safe is to investigate vaccination, understand the benefits, understand the risks, and make decisions to participate in vaccination programs. For the benefit of everyone.

[01:07:34] Angela: Thank you very much. there's this underlying message, which is that we all need to communicate better.

[01:07:39] Angela: I think as, medical experts, public health experts , we have, we have Expertise. We have knowledge on somehow all these years. We have not managed transfer it effectively. there are other voices in the room that are so effective, so loud.

[01:07:56] Angela: and they're not the voices of experts.

[01:07:59] Angela: Science communication, we've got to do better. I think in 2025, now really the, forces of, chaos unleashed and we have to do better with getting our knowledge and, the data out there. So, thank you so much to our two guests, Kerrigan McCarthy in Johannesburg, South Africa, and Bernard Hirschel here in Geneva, Switzerland, and thank you for listening to Communicable, the CMI Comms podcast.

[01:08:24] Angela: This episode was hosted by myself. Angela Huttner, Editor in Chief at CMI. com's ESCMID's Open Access Journal. It was edited by Dr. Katie Hostetler Oy and peer reviewed by Dr. Barbora Piszczowa of the Institute of Tropical Medicine in Antwerp, Belgium. Theme music was composed and conducted by Joseph McDade.

[01:08:44] Angela: This episode will be citable with a written summary referenced by a DOI in the next eight weeks, and any literature we've discussed today can be found in the show notes. You can subscribe to Communicable on Spotify, Apple, wherever you get your podcasts, Or you can find it on Eskmit's website for the CMI comms journal.

[01:09:03] Angela: Thanks for listening and helping CMI comms and Eskmit move the conversation in ID and clinical microbiology further along.