Covid-19: hindsight, usefulness, dosage … 6 questions on childhood vaccination

It is a new step towards the vaccination of French children. The opening to every 5-11 years appears close this Friday after a favorable opinion from the National Consultative Ethics Committee (CCNE), however laying down many conditions, starting with the exclusion of any obligation, and the implementation health pass as is the case for adults and adolescents.

But the subject is sensitive, with more than two-thirds of parents opposed to having their children vaccinated, according to an Elabe poll for The Express, BFMTV and SFR released Thursday. On the side of scientists, the question of the risk-benefit balance is also the subject of heated debate.

For many, it is the hindsight on the effects of vaccination on the youngest that is lacking to take the plunge. On the side of the parents, Laurent Zameczkowski, administrator of the federation of parents of pupils Peep, specifies that the concern carries “mainly on the long-term effects”. Some “fear making a decision that will heavily impact the future of their children when they seem not to be in danger with the Covid except in particular pathological conditions as the HAS emphasizes” he explains.

And to continue: “We feel that scandals like Distilbene, even if it is a treatment, still carry a weight like the doubts that still exist about the hepatitis B vaccine or even the papillomavirus.” At Le Télégramme, Christèle Gras-Le Guen, head of pediatric emergencies at Nantes University Hospital and president of the French Pediatric Society, also believes that“we do not yet have sufficient hindsight”.

“The decline in terms of tolerance of vaccination of young children is very limited since, in clinical trials, there are still not many children”, abounds with Franceinfo, Daniel Floret, vice-president of the technical commission of the vaccinations of the HAS. “We will soon have the data of the American experience since the Americans will have vaccinated several million children so, if there are particular problems of tolerance, it will appear in clinical trials”, he specifies.

On November 9, The New England journal of medicine published the results of a study carried out on 1,517 children with Pfizer’s serum, and presenting the administration of this vaccine as “safe”, with 90 to 96% effectiveness. According to this study, the side effects mainly concern pain in the arm following the injection (71% of cases), fatigue (39% of cases) and headaches (in 28% of cases). If the sample was slightly enlarged at the request of the American control authorities (FDA), the number of children included in this study remains too low to comment on the serious side effects, which are rarer, in particular the risks. cardiac pericarditis and myocarditis.

Note that before opening the vaccination to 5-11 year olds, Canada carried out a “thorough and independent scientific review” from “evidence”, concluding with similar results. It is also on these that the European Medicines Agency (EMA) relied to approve the American vaccine on November 25. “The side effects, which can last for a few days, were found to be mild or moderate”, reassured Marco Cavaleri, head of the vaccine strategy of the EMA. The returns from different countries, having launched for several weeks or even several months in the vaccination of children, seem to go in this direction. It remains to be seen whether the pharmacovigilance data collected from large-scale childhood vaccination in countries that have already authorized it will also confirm the absence of rarer side effects.

According to the French High Authority for Health (HAS), children remain 25 times less likely to develop a severe form of the disease. From a medical and individual point of view, the benefit of vaccine protection therefore appears to be much more limited than for adults, and a fortiori than for seniors and people at risk. “For it to be effective in protecting serious forms, we need three doses, children do not have severe forms, and before they have three doses, we will have another vaccine”, asks for example a parent describing himself as “pro vax” on the Web, when a second writes: “Isn’t it better that the children catch this virus as long as it does nothing to them, their immunity will be a priori better than with a vaccine which only encodes the Spike?”.

If there is any benefit, it is in fact essentially collective, such a measure aimed at preventing children from becoming the main vectors of the epidemic. Children would thus help protect their parents, and their grandparents. On this point, the learned pediatric societies published a press release on November 15 in which they believe that the “collective benefit” would “uncertain”, given the relative efficacy of the vaccine against virus transmission.

The CCNE affirmed to have decided indeed according to the individual interest for the children, much more than of the collective benefit for the whole of the company. “The risk of severe form exists (even if) it is low”, notes obstetrician Alexandra Benachi, member of CCNE. “Why should we accept that children are hospitalized or have long-lasting sequelae of Covid? In the United States, more than 3 million children have received the vaccine, and there are no reported cases of myocarditis”, advances epidemiologist Dominique Costagliola who is also worried about the conclusions of a recent study, carried out in ten European countries. “This survey confirms that the hospitalization rates are very low, but that, among them, 83% of the children had no risk factors. Is it considered serious or not? “.

In addition to the purely medical aspect, it evokes the importance of avoiding class closures while contaminations soar among children. But from the point of view of learned pediatric societies, the “social” benefit is less important than in the United States, for example, where classes had been closed for forty-seven weeks, against only ten in France. More generally, they consider in their press release of November 15 that the “direct individual benefit” for children would be “very modest”, given the low number of serious cases in this population, namely 3 deaths, 226 stays in intensive care, 351 pediatric inflammatory syndromes and 1,284 hospitalizations recorded, according to Public Health France.

To prevent children affected by Covid in recent months from receiving two doses, the Vaccine Strategy Orientation Council recommends systematizing serological tests. Objective: to determine in a few minutes, via a drop of blood, if you have been previously infected with the virus. If so, a single dose is sufficient to provide optimal protection. Otherwise, two injections are still necessary.

As a benchmark, the COSV, chaired by Alain Fischer, estimates that a significant proportion of those under 12 have contracted Covid-19 since the start of the pandemic. “An HIV positive rate of 18% was recorded in June among children of this age group”, he said in a notice made public on Wednesday. “This figure is likely to be significantly higher in the context of the fifth wave”, while the incidence rate of young people is one of the highest in the country.

“Data from clinical trials have shown that with a dose reduced by a third of the amount of RNA, we can protect children well and apparently things are going well.”, clarified on LCI the Chairman of the Steering Committee for the anti-Covid-19 vaccine strategy, Alain Fischer, insisting on the fact that it is the same vaccine as for adults “but at a reduced dose”. “10 micrograms of Pfizer instead of 30 to be very precise”, he detailed.

As such, the color of the caps of vials intended for young children, orange like the label border, makes it possible to distinguish them from those containing a higher dose, as a reminder to purple caps.