Flu shots for children? Why this should be more on the radar

Clare Taylor: 0:14

Hello and welcome to ESWI Airborne, the podcast series of the European Scientific Working Group on Influenza. This is your host, Clare Taylor, and this is the place to be to meet one-to-one with the members of ESWI, learn more about their work and why they do it. Today I have the great pleasure of talking with Terho Heikkinen, professor of paediatrics at the University of Turku, Finland, and board member of ESWI. Terho, welcome to ESWI Airborne.

Terho Heikkinen: 0:48

Thank you, pleasure to be here.

Now, Terho, today we're going to talk about the important topic of influenza vaccinations for children. But first I'm curious. Your major research interest is in respiratory infections, especially in children. How did you get started in this field?

Well, after I graduated from the medical school, I worked for a couple of years as a general practitioner in the outpatient setting and during those years I saw the huge burden that respiratory infections place on children. So when I started my residency in pediatrics, it was pretty obvious that pediatric infectious diseases would be my own subspecialty.

From there, your doctoral thesis, which you defended in 1994, was on the topic of development and prevention of acute otitis media in children. Can you just explain to me and to our listeners what is acute otitis media?

Yes, of course. Acute otitis media means infection in the middle ear. Usually people just talk about ear infections, but acute otitis media is kind of the official term originating from Latin. Ear infections are extremely common in young children, and actually they are the most frequent reason for using antibiotics in children all over the world. My thesis work focused on the role of viruses in the development of these ear infections and especially on what could be done to prevent these infections.

And indeed, speaking as a mother, I'm sure many of our listeners also will know how painful those ear infections are in children. And at the time that you were doing this work, your doctoral thesis, you were still in Finland right at that time and from there you went on to Texas, to Galveston. Can you tell us a bit more about your experience there?

Yes, I had the pleasure of spending two years working as a postdoc researcher, as we call it, at the University of Texas in Galveston, and that was a great time, not only for myself, but also for my entire family. My supervisor there was Professor Tazni Chonmetri, and she had also a great interest in the importance of viruses in otitis media. So that two years time was extremely fruitful and productive, also in the academic sense.

And gave you, no doubt, a very strong foundation from which you have built an extraordinary career. Particularly, I note that you have been actively involved in international research collaboration and very active as chairman or board member in organisations working on pediatric infectious diseases. Where are you most engaged and what do you hope to achieve with this kind of participation?

Yes, I've had the great privilege of working in several major international societies, including as the president of the World Society for Pediatric Infectious Diseases and also in the board of European Society for Pediatric Infectious Diseases. Those are really great experiences. At the moment, besides ESWI, of course, I'm mostly engaged as a founding member of Resvinit, which is a global research organisation focusing on respiratory syncytial virus, and I'm also the chairman of the Nordic Research Network for Pediatric Infectious Diseases. So what's my mission? I could say it's trying to find new and effective ways to reduce the burden of respiratory infections and their complications in children.

So reducing that burden of illness brings us on to the burning topic of the day vaccination in children, in particular influenza vaccination. Now, Terho, do children really need a flu vaccine?

Well, the short, and simple answer is yes. There's ample evidence for the great burden of influenza in children, especially in young children. It's on many levels. Although children rarely die of influenza, the rates of influenza illnesses are always highest in children. The rates of complications such as ear infections are highest in children, and young children are frequently hospitalised with influenza, and all of these can be effectively prevented by vaccinating children against the influenza.

Now, Terho, when we're vaccinating children, are there special doses of the vaccine that are manufactured just for children? I'm wondering this because they're smaller. Maybe they don't need as much. What's your take here?

During previous years, many countries have been using half doses in young children, but there's an increasing number of countries that have started using the full dose, the exact same dose as we give to the adults. And this has been, for instance, the situation in Finland, where I live, where influenza vaccination was included in the vaccination programme for children already in 2007. And we've had no negative experiences of using the same dose, the normal dose, that we give to the adults, the same dose to the children, and the efficacy has been good.

Now, like many of our listeners, I'm sure I'm a parent. I want to make sure that my children are protected, but I don't want to overprotect them. What age children do you recommend a flu vaccine for, and why?

Well, it's very difficult to draw a sharp line here because everyone, whatever the age of the person, will benefit from the vaccination. But overall I would say that the burden of influenza is clearly greatest among the youngest children, let's say up to three years of age. The WHO recommends influenza vaccination of all children up to five years of age, so perhaps something in that range is the age group that would benefit most from vaccination.

And how about when children are at their most vulnerable, when they're young babies say younger than six months. Can you give a vaccine then?

No, it's a sad thing that infants less than six months of age cannot be officially vaccinated against influenza, and this is exactly one of the biggest problems, because the youngest children also bear the highest burden of illness. The best way of preventing influenza at the moment in these children is by vaccinating the parents and siblings and other close contacts of the baby. This is called a cocooning strategy, and once the infant grows up and gets older, then the child can be vaccinated him or herself. It's also important to remember that, although we cannot vaccinate the youngest infants, there is fortunately an antiviral drug available for these situations. So when a young infant gets sick with influenza.

So cocooning is the first strategy you would recommend to protect a young baby.

Oh, yes, absolutely, and the most effective.

And the most effective. I have to admit, this has not really been on my radar as something I should do for my children or even for myself. Now, earlier you mentioned the WHO recommendations. Can you give us a snapshot of the government or health authority guidelines here?

Actually, this is one of the most important questions when discussing influenza vaccination of children. There are several expert groups and different organisations that during the years have published their recommendations to vaccinate children, but eventually it is the individual country where the child lives and that country is fully responsible for its own vaccination programme. Even in the EU, there is no health authority that could tell which vaccines should be included in the member countries vaccination programme. So this means that there's a lot of variability between the recommendations in different countries and at the moment some European countries do recommend the influenza vaccination of healthy children and have included it in the official vaccination programme, which is fully reimbursed, while many other countries are still thinking about it or have even decided not to include influenza vaccination in their programmes. So it very much depends on the country where you live.

So it depends on the country where you live, there is still some variety here, let's say at national government level. How safe is the flu vaccine?

The safety of seasonally influenza vaccines has been very, very well demonstrated. These vaccines have been used in hundreds of millions of people during several decades, so safety is not an issue at all. It has been so well shown.

Well, that is very good news indeed. Are there any side effects of the flu vaccine in children? For example, how often is it that my child could run a fever after receiving a vaccine?

It's extremely rare. The situation is similar to any other vaccines that are given by a needle, so there could be some local pain or redness at the site of the injection, but usually that's very short-lived and mild, so not a big problem. There is another type of influenza vaccine, so-called live attenuated vaccine. That is administered in the nasal cavity, so it is given as a nasal spray and sometimes, in rare cases, that may cause mild respiratory symptoms because it's a live virus. But even in those cases there will be no flu-blown influenza and, especially when using this injectable influenza vaccine, it is 100% impossible to get influenza from the vaccination, although many people think that could be the case.

Okay, that is interesting and news to me. Indeed, I suppose another common prejudice against the flu vaccine is the idea that you or your child could get the flu vaccine and still get the flu. Could you talk a bit about this please?

Yes, that's entirely possible. The efficacy of influenza vaccines is not 100%. The underlying problem is that the structure of influenza viruses changes all the time when they go around the world. That is a phenomenon called antigenic drift and in some years the evolution of viruses is very fast, and because it takes a long time to produce the vaccine, approximately six months, by the time that the vaccine is ready, the virus may have already changed so much that the vaccine is not fully effective anymore. And this is the reason why we need new influenza vaccines every year that are as closely tailored to the circulating viruses as possible. But they can never be 100% matched to the circulating viruses because of the changes happening in the virus. So even vaccinated people can catch influenza, but in those cases we call them breakthrough infections. The disease is usually much milder than the natural illness.

And on that, do you have any statistics on the percentages of people, or even children, that get vaccinated and still get a flu, or any idea of what the proportions are?

You could say in general, the efficacy of the vaccine, on average is between 60 to 80%. In some years it's even higher. But in years when there is a serious mismatch between the circulating virus and the virus in the vaccine, the efficacy could be much lower. And that's one of the biggest problems when we're talking about production of influenza vaccines today.

But in a regular year, with an efficacy of 60 to 80%. This sounds like something that is actually worth doing, right? Something you would take a bet on, if you like. I'm living, I'm a mother, right, I'm living in Brussels, in Belgium. Where would I go to get my child vaccinated against influenza?

Right now don't go anywhere because it's springtime and this is not the time for influenza vaccination. Influenza vaccines arrive in the autumn, and so the next time that this question is timely, it is next autumn, when I would propose that you see your general practitioner or family physician, depending on where you are and how your health system is.

Thanks for that. I will certainly bear that in mind as the days grow short next autumn, terho, what would you like to see happen, say over the next couple of years, on public awareness on this issue?

Certainly, I would hope that the general understanding about the great burden of influenza in children would increase. That would mean that then parents would start asking about the vaccination for their children, even in countries where the vaccination is currently not included in the vaccination programme. So general awareness of the burden is the key, I think. If I might make a couple of more wishes, I would certainly wish a vaccine for infants who are younger than six months of age. That's theoretically possible. And another thing is that I would very much like to see finding ways to produce even more effective vaccines, vaccines that could overcome the problem caused by the constant changes in the structure of influenza viruses that we just talked about.

So this marvelous phrase, that antigenic drift, that is the evolution of the virus all the time and therefore the need to develop new vaccines against it. Is that right?

Yes, if we had vaccines that don't care about the drift, but that would be effective against all, even the drifted strains, that would be the perfect situation.

Terho, thank you so much for taking the time to explain all of this. I've learned a lot from you today.

Well, thank you. My pleasure being here.

Folks, that is the last word for today on influenza vaccinations in children from ESWI board member Terho Heikkinen. Thanks for listening. Keep tuning in to ESWI Airborne and until next time, stay safe.

Aida Bakri: 18:58

ESWI Airborne is brought to you by ESWI, the European Scientific Working Group on influenza and other acute respiratory viruses. Special thanks to our ESWI Secretariat, our technical and IT teams, our arts team and our host, Clare Taylor. The podcasts are recorded virtually and we thank our guests for their participation in this inspiring and educational series. Talks are adapted to a global audience and are intended as recommendations and guiding principles. For any specific medical questions you may have, these should be addressed to your local general practitioner. Many thanks to our sponsoring partners and thank you for listening.

Flu shots for children? Why this should be more on the radar

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