Covid-19, all infected this winter? Why a 4th dose for all is not on the agenda

Gilles, in his forties, athletic, has very bad memories of his two episodes of Covid. While he had so far escaped the virus, he was overtaken by the highly transmissible Omicron. “The first time, I was really bad, with a cracked rib from coughing. And the second time, it was hardly better”, says this Lyonnais. So for him, it’s sure: whatever happens, he will be revaccinated. “I want a fourth dose, to put all the chances on my side not to fall ill again,” he insists. Even if it means ignoring the advice of the health authorities, who for the moment only advise this second reminder to people at risk.

An isolated case, Gilles? Not really: “We regularly have requests from customers who are not in the target population for a fourth injection. When we have doses available, for example because a vial has been opened, we administer them to them rather than lose”, confirms a pharmacist member of the USPO union. Currently, only 40% of those most exposed to serious forms (over 60, immunocompromised, pregnant women, etc.) have received their fourth dose, although this is still strongly recommended to them. But conversely, some of the French, younger, healthy, and triple vaccinated for several months already, would like, like Gilles, to protect themselves from the virus as winter approaches.

At this stage, however, there are no plans to relaunch a new vaccination campaign for the general population. “The priority is fragile people and those around them. If we reopened vaccination to everyone, the message would be diluted and we could miss these audiences who absolutely must be protected”, underlines Professor Alain Fischer , who chaired the Vaccine Strategy Orientation Council until June. In the current context, with a large proportion of French people already vaccinated and/or infected several times, the collective benefit of a new dose for everyone would be limited anyway: “The variants in circulation continue to be recognized by our system immune: for young people in good health, the probability of developing a serious form is very low. Under these conditions, it is better to allocate our resources, which are necessarily limited, to other priorities”, confirms Professor Jean-Daniel Lelièvre, head of the immunology and infectious diseases department at the Henri-Mondor hospital in Créteil (AP-HP) and member of the technical commission for vaccinations of the Haute Autorité de Santé.

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“The current variants do not seem to completely escape our immunity”

This protection against the risk of hospitalization or death in people without risk factors is also long-lasting. “Neutralizing antibody titers decline over time, making reinfections possible. In contrast, memory cells, made after initial exposure to the virus, last a long time, probably much longer than a year. do not prevent infection, but after 4 to 5 days they will block viral replication”, continues Professor Lelièvre. At this stage, only the emergence of a totally different variant could therefore change the situation and make it necessary to protect the entire population. We are not there, including with the newcomers (BA 2.75.2…): “They are more resistant but they do not seem to completely escape our immunity”, underlines Professor Fischer.

Wouldn’t an additional dose of vaccine make it possible, all the same, to avoid, on an individual basis, the inconveniences of a new infection and the symptoms that can accompany it? “Of course, because it will raise the levels of neutralizing antibodies. But this protection will not last more than a few months, so the interest remains modest”, indicates Professor Fischer. With a virus that continues to circulate actively, many French people are therefore at risk of reinfecting themselves during the winter. Not enough, however, to worry these experts: “The successive infections are generally less severe than the first, because we acquire an increasingly important immunity”, specifies Professor Lelièvre. Even the possible occurrence of a long Covid does not panic them: “We do not yet have fully consolidated data, but it seems that this risk mainly concerns primary infections”, assures Professor Fischer.

All things considered, the current situation would therefore be closer to that of the flu. “Influenza vaccination is only recommended for people at risk and for caregivers, but if other people want to protect themselves, they can do it too. It’s the same for Covid”, explains Professor Lelièvre. If he still wants it, Gilles should therefore get his fourth dose…