Pertussis

To tell us how to diagnose and manage and prevent patients from getting this disorder, we have on the line Professor Sir Andrew Pollard, Director of the Oxford Vaccine Group, and Ashall Professor of Infection and Immunity in Oxford. So Professor Pollard, you're welcome. Let's start off with a fairly straightforward question What exactly is this condition?

And that happens whatever age you are, if you get patussis, you get a prolonged cough. But it is particularly serious in younger children, particularly in infants. who um can become apneic as a result of the uh the cough, the long uh repeated coughing can result um in a hypoxia and injury from that. But we also see babies who have very little cough, particularly the the youngest ones a few months of age, who may just stop breathing.

And uh certainly as a as a pediatrician uh practicing infectious disease, I um over the years have seen many babies in intensive care units. who are ventilated because of um apnea um or because they just cannot avoid hypoxic episodes because of the severity of the coughing. I mean, it is worth also saying, um, that in older children and also in vaccinated people, patusses can still happen.

But it tends to be a slightly different syndrome. And a really common thing I hear about as a pediatrician is a story of someone referred because they're vomiting. And but actually when you take the history very carefully, they're vomiting because they have a prolonged cough and they tend to vomit at the end of that that cough. So vomiting on the playground is often patussis.

How do you make the diagnosis of

Um because obviously there are many respiratory viruses which will make us cough for several weeks, um both with the acute infection and then as as the respiratory mucosa recovers. But a prolonged cough um is likely to be patussis and the misdiagnosis there is usually of asthma and many children, um older children we see treated uh for asthma before the penny drops and people realise it's actually patussis.

Um so I think uh that that history is really important. Another really key element of the history, uh particularly in infants, is that another member of the family has been coughing. And the typical story actually is it's the mother um who ha often has the closest contact with an infant who has had a a cough that's been going on for some weeks, and then the infant pr presents with apnea or or with um a very severe cough.

Once you have uh the clinical diagnosis, um or perhaps if you're aware of contacts of batussis, Um the diagnosis is uh today made on PCR um that is undertaken from a nose swab and that's taken early on in the illness, um, usually positive within the first few weeks of the illness.

I mean it's worth saying that the clinical syndrome is not just about the cough. It's just it's the cough is the only bit that we really recognize um uh in real life as clinicians. But if you track back to how the illness starts, It starts very much with a chrysal illness, um, with um runny noses and feeling completely bunged up before the coughing begins.

And it's that period, um, which is extremely difficult to recognize in most cases. But if you know about contacts, then the really reason why that's a really important phase is it's the one phase of the illness which is potentially treatable. uh with antibiotics, which might not have a huge impact um overall, but it really does have a an impact on spread of the bacterium that causes patussis.

Um I we don't see it very often in the youngest infants who who have um patussis and particularly with in a relatively highly vaccinated population, it's a bit less common in older children and adults than than it was in the past. it is an important sign to uh to recognize when it's there. Um, but it's really not a a major part of what what you hear about from parents Um and actually you don't so often uh observe it clinically either.

Um, and as it gets further through that period, it becomes increasingly unlikely to be positive. There are serological tests which um are used. Um and you if you have very high levels of antibody to some of the potasses proteins and that is uh measured by the public health agency, the UK Health Security Agency,

um there is a a view that you can separate these out from vaccinated antibodies. Um and uh so that may be used in some cases, but this is I think once you got past the PCR point Largely this is a clinical diagnosis.

Any other pitfalls in diagnosis other than the ones you mentioned?

And uh so one of the difficult things to explain to uh families here is that we're gonna give you antibiotics to stop spread, but your cough may still go on for three months or so. And uh obviously some don't last as long as that, but it's not uncommon to have a cough that continues for two um or three months. It's very debilitating. And when you take the history from families, you you often hear the story that

Um, apart from coughing on the playground, which I mentioned, which tells you that once you're exerting yourself you're more likely to cough. But the other and is being woken up at the night day after day by the child coughing. Um and so it seems to be particularly bad in the nighttime, um, which both for the parents and the child is um is uh that means that they're lacking sleep and particularly cross with you when you do see them.

Um and then in terms of management, it's apart from that antibiotic therapy, it is supportive care. So if they need respiratory support, which is only really in very early infancy, that's in the hospital for older children and adults. Um, it's really reassurance that uh that uh that this is likely bitassis and it will get better. Uh, with a child that's awake every night, three months feels like a very long time.

Or is it uh is available as a as a a four in one vaccine. Really the uh the the most important part of this disease is the is the unvaccinated infant, because that's where almost all the deaths from patussis occur. And so an important change uh um over the last decade has been securing maternal immunisation.

um which is now uh a routine offer in pregnancy. And that's because a lot of the deaths happen in the first few months of life before we've had time to give the first dose of the potassius vaccine. And that maternal antibody very effectively protects um infants. In the year that uh this was initially brought in as an emergency.

Um, about fifteen years ago, there were eight deaths in that year. And uh introduction of the vaccine has mitigated that. So it's very unusual for for Hoopinkoff deaths to happen.

Unfortunately, we have seen both a fall in maternal vaccine coverage and in infant vaccine coverage over that that decade. And as a result of that, we we're actually in the middle of a a patussis outbreak over the last um twelve months or so, uh where we're seeing a lot more cases and we have had some more deaths associated with patussis in infants as a result of that. So one of the challenges here is that the vaccine is highly effective. We don't have the massive outbreaks we had.

Um, before a f uh a proper centrally coordinated programme which started in the nineteen sixties, we used to have massive outbreaks um of potassius with tens of thousands of babies affected and many deaths. Um, since the vaccine's been there, that really has reduced considerably. But the vaccine we have is incom it i it's incomplete in its protection, though it's leaky. So we even when everyone's vaccinated, we do see cases

uh that still occur. Uh but the severe cases and deaths can be largely prevented by vaccinating infants and the mother and to deal with the first few months of life. What does happen with the vaccine, um, apart from it not providing a hundred percent protection, is that protection wanes over time. so that older children and adults um may well have um modified hooping coughs are not as severe as it would be without vaccination, but it we don't get lifelong protection from the program we have.

And this this is an a an unfortunate problem. We have a very safe hooping cough vaccine. Um there there are uh the original vaccine which in fact most older adults had, including myself, which was a whole cell pathosis vaccine. That protection was a little bit better than the current one. That's used in most of the developing world, but it was more likely associated with side effects.

I mean the infant, um particularly things like prolonged screaming and uh hypotonic, hyper responsive episodes, which were pretty scary for us pediatricians when we saw them, but they were completely self resolved. And the newer vaccine, which is just a um a multi component protein vaccine, is much safer. It doesn't cause those side effects. Um but it uh does uh despite that um have slightly um poorer duration of protection.

Um, there are uh a a large group of individual who have uh have completely rational questions that they want to ask about vaccination. I think uh all of us very keen to ask questions about our health, particularly when uh the solution is delivered on the end of a needle, we want to really understand why. And so you also need access to trusted health professionals who are able to counsel about that. And the surveys in this area in the UK suggest that the person

And the people most trust for giving advice is the GP. Um, unlike other countries where it's the pediatrician who's the uh the primary vaccinator and is the most trusted in in the UK, it's the GP. And uh that is um a very uh rare resource that we have um still in at the moment. And so to to be able to deal with that we need better access to the immunisation service as well as to expert

um help from primary care to give advice about vaccines. Um clearly there's there's also a a as well as that more hesitant group who usually will be vaccinated when they have the right advice. There's a very small anti vaccine uh view that's out there.

But the evidence we have is that's not a major component of the reason for undervaccination. Um it's it's much more um indifference, a bit of lethargy, and the that it's not easy to get vaccinated or get advice about vaccination that's um allowing the the rates um to fall.

Um and you just uh don't want to discuss it, you you want to um uh make sure that someone who has the right knowledge is dealing with that. And I think that's the more common scenario is that we're just I think it's really important that we do, particularly those of us who deal with families, build confidence around immunization for ourselves because this discussion can be a life or death discussion for an infant.

um if uh if we're not giving the messages clearly. And that is not just for doctors, it's important for midwives, particularly around maternal vaccination. practice nurses who usually are the real experts in immunisation because they do most of it, um, and GPs.

to see what the real benefit public health wise would be for the population. And there is very little evidence that by giving a booster to teenagers that you'll reduce And the burden on the health system, which is around deaths in infants, hospitalisation in infants, because teenagers don't tend to spend much time with with babies and so they're not really driving transmission in babies. So it's i the the teenager booster may have some benefits for teenagers.

But those are not really teenagers who in the way that we calculate cost effectiveness in the NHS, they won't have a big burden on the health system. And so the the cost Um, it's very difficult to uh to balance um against the benefits when you come to teenage vaccination, which is for the simple reason it's not included thus far in the programme.

protects against hypoxia and brain injury, it doesn't cause it. And uh so we we need to be very robust about the safety of these vaccines that we have in the program.

Um i in the naive individual, uh, you might also find a very high lymphocyte count, and we see that in I'm in babies with patussis particularly.

And uh uh but you know, I think uh there aren't particularly questions around Patasis itself which are difficult to answer because we have a lot of information. Uh the sad thing is that sometimes the answers aren't the ones that families want to hear and certainly we've been in pretty dire situations in the intensive care before. I've seen babies die from patussis. Um and uh th those are very little conversations to have and they're not ones that you ever want to be in a situation to discuss.

particularly in the scenario where you know the reason why that's happened is because the mother wasn't vaccinated in pregnancy um or that someone in the family didn't have their vaccine dose. And that's why it's so important that we continue to fight and champion vaccination.