From the resurgence of measles to innovation in the fight against RSV, 2024 was a pivotal year in infectious diseases. Dr Benjamin Davido takes stock of the challenges encountered and the progress made. As France positions itself in the face of antibiotic resistance, new vaccine strategies could redefine the approach to infectious diseases.
TRANSCRIPTION
Hello everyone, welcome to Medscape, I am Benjamin Davido, infectious disease specialist at Raymond-Poincaré hospital, and medical advisor to the DGS on the mission of antibiotic resistance.
I am delighted to provide an update with you on the key developments in 2024 in infectious diseases. So obviously, there are a lot of things to say, I had to make a choice, but I first wanted to come back with you to the worrying increase in measles cases.
Increase in measles cases
This increase in measles cases was marked by a vaccination campaign which, as we know, has been insufficient in recent years, and not only in France, but also in the rest of the world. And they are almost surprising in the end, these figures in 2024 for the resumption of measles. Because we must remember that in 2023, after data from the French public health bulletin, we welcomed a historically low record figure which we attributed mainly to the 2018 vaccination obligation. And we still see the importance of having the most exhaustive figures possible. We know that for measles, more than 95% of the population must be vaccinated to obtain these results. In a post-pandemic world where we are in contact with each other between different countries, the importance, if we want to reduce this risk, is to have a global health policy.
These data are all the more interesting since this vaccination against measles and this crisis of the resumption of the disease took place in 2024 at the period which we had a lot of fears about due to the Olympic Games. And it must be admitted that from the infectious aspect, the Olympics went rather well. It has been relatively calm.
Summer recovery from COVID-19
Another interesting fact: a significant summer resurgence, like every year, of COVID-19, which is, in quotation marks, a ”new disease” to which we were not really accustomed and which appeared during the Tour de France , but also during the Olympics with sometimes certain athletes who chose to take time off from events to let this episode of COVID pass.
The return of whooping cough
Likewise, we had a completely unprecedented resurgence which was explained by a cycle of whooping cough every 5 years, therefore five years. But in fact, we don’t really know how to explain this whooping cough cycle since once again, we know that the risk is major in children – and we are on broad vaccination strategies for children. We know that there is obviously a delay with ideally 3 vaccines for children to avoid finding themselves in the gap in the vaccination schedule. But we also know that it is to be congratulated. Since 2023, we have recommended the vaccination indication with booster shots at each pregnancy in pregnant women to allow passive immunization in children during their first 5 months of life. And we unfortunately know that in this ”racket hole”, we have family situations, leisure centers, communities among children which mean that the older ones – caricatured after 2 years, those over 5 years old and adolescents — often have this gap in the vaccination schedule and this leads to epidemics of whooping cough… another forgotten disease that has returned in an unprecedented way.
Imported cases of dengue
We can also quickly say a word about arboviruses. We were very concerned since: for example, from January 1, 2024 to May 1, 2024, we had more than 1,680 cases of dengue which were in fact essentially imported forms of the disease. And despite the very widespread implementation in France of the tiger mosquito and the fear of gatherings during the Olympic Games, we have not seen a rebound situation; even if we must still admit that from May 1 until November 26, 2024, we had approximately as many cases (i.e. 2028 cases), but mainly cases of importation (mainly for the trio Guadeloupe, Martinique and Indonesia).
The cards are redistributed again for 2025, we will see to what extent these arboviruses, mainly dengue and chikungunya, can take hold and make a resurgence.
Respiratory diseases: influenza, RSV, pneumococcus
I will end on the general aspect of respiratory diseases. We talked earlier, quickly about COVID-19 which mainly created mild forms this summer, including among athletes; in the same vein of these respiratory diseases, it must be emphasized that we have a great need to protect ourselves from these triple epidemics which are COVID, influenza and RSV.
Precisely on the flu, Germany is a step ahead of us in Europe since it started this year to vaccinate with a “simplified” vaccine, that is to say a trivalent vaccine (vs. a usually quadrivalent) of strain A including H1N1 and 2 strains B this time. Exit the B-Yamagata strain. For what ? Because we have noticed since surveillance with COVID-19 that barrier gestures have completely chased away and displaced these strains. It’s quite interesting. And so the choice was made by the WHO to say that we can now offer a trivalent vaccine rather than a quadrivalent vaccine.
I point out the fact that we are removing strains when they are not necessary, and this is something good and which will extend to all countries, including France, from next year in this flu vaccination. What we can note, however, and which is not necessarily good news, is that last year and this year, we were not able to benefit from the high-dose vaccine in people over 65 years old. which we should have, I hope, for the 2025-2026 season and which makes it possible to reduce, among the most vulnerable people, hospitalizations for respiratory diseases by up to 25%.
We also mentioned RSV, this famous bronchiolitis virus, one of the big news in 2024. There was the provision of 3 vaccines, including one with messenger RNA which will be currently being validated. And the good news is that one of these vaccines has obtained marketing authorization for vaccination prevention in pregnant women in order to cover by passive immunization, for the same reasons as those for whooping cough, COVID or flu, RSV unborn children. So pregnant women, between the 32nd and 36th week of pregnancy are eligible for this type of vaccine. This is a new strategy which makes it possible to support monoclonal antibodies of which we know that the reserve is limited. And we know this year unfortunately that we still have a heavy burden of bronchiolitis in children. We have this domino effect, of being able to protect both pregnant women and on the other hand the most fragile, according to the recommendations of the HAS from the age of 65 with a new vaccine. The limit, probably, will be to see how we manage to put together these vaccines, which for the moment have data for 2 to 3 years and which, through a single dose, provide coverage against an essentially seasonal disease. One of the challenges for 2025 will be to find the right period and how to organize this vaccine.
We have had the update of the pneumococcus vaccination schedule with, for children, a PREVENAR 15 which makes way for the PREVENAR 13 and for adults, a PREVENAR 20 which is already available in 20 valence and which greatly facilitates the administration with a conjugate vaccine in a single dose until further notice (until new recommendations) and which will be supplemented, it is hoped, next year by a 21 valent vaccine so as to have as many strategies as possible to protect against respiratory infections.
Update of the meningococcal vaccination schedule
Finally, I will end in a word to say that there has also been an update of the meningococcal vaccination schedule in children in the face of a change in circulating strains, in particular for the benefit of W and Y, and that overall in children, the ACY strains have been replaced in the vaccination of children under one year of age by an ACWY vaccine from the outset.
And this vaccination, which we know is compulsory in children, will become ACWY. In adolescents, it will be recommended given the risk of serious invasive meningococcal infections and the implementation of these effective vaccines.
Fight against antibiotic resistance
To close this discussion, we can be pleased that France, at the European level, is a major player in the fight against antibiotic resistance in 2024. France is in fact coordinating the joint action of JAMRAI ( J oint Action on anti-Microbial Resistance and healthcare-Associated Infections) which started this year and which will last 4 years, therefore until 2027. France is a stakeholder in the decisions, in commitments on a European scale in the face of antibiotic resistance. It should be remembered that in this 2nd edition, France coordinates and plays a role within the ministry on the sustainability of the action; ANSES also participates in the surveillance networks. This first joint action ended with the creation of a strong symbol, which was that of [emblème] of antibiotic resistance.
I thank you for listening and I hope to see you soon in 2025, with so many new features rich in news and infection control prevention. Very good day to you.
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