After several days of debate, France finally retains the period of three to four weeks for the injection of the second dose of the Pfizer and Moderna vaccines. Olivier Véran, the Minister of Health, dismissed this change in protocol concerning messenger RNA vaccines on Tuesday morning at a press conference.
This decision goes against the recommendation of the Haute Autorité de Santé, which argued for the postponement of the second injection of the Pfizer and Moderna vaccine to six weeks (42 days) against three to four weeks according to clinical trials (21 days). for Pfizer, and 28 for Moderna) “in the current context of a resurgence of the epidemic”.
According to the HAS, this would in fact make it possible to vaccinate 700,000 more people the first month of implementation of this measure, to speed up the primary vaccination (ie the first injection which allows the start of protection).
A risk of loss of efficacy for the elderly
But “this scenario does not achieve consensus in the scientific community”, as recalled by the Minister of Health, and Professor Alain Fisher. “More people vaccinated does not mean more people protected”, explains Professor Fisher.
And increasing the number of people who have received a first dose does not guarantee, in the long term, an increase in the number of people vaccinated.
Moreover, after the first dose, “the protection may be less effective in older subjects” in the general population, as the first data from mass vaccination in Israel show. This does not argue for a separation of the second dose, which remains essential to induce real protection.
And “we do not know at all the consequences of the separation of doses”, especially in the elderly. “Is there not a risk of a suboptimal immune response”, which could reduce the effectiveness of vaccines against variants, continues Professor Alain Fisher.
Finally, “the longer the time between appointments, the more people are at risk of forgetting their second appointment”. This also risks delaying the first appointments made for the recall, which the Minister of Health wishes to avoid.
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