Modification of the vaccine schedule against SARS-CoV-2 in the new epidemic context

HAS considers that:

• the administration of a second dose for the two currently available mRNA vaccines remains essential for long-term protection;
• the vaccine efficacy observed in clinical trials appears high enough between the two doses to consider a spacing of the interval between these two doses, despite the uncertainties not yet resolved, in view of the expected benefits in the coming weeks in terms of coverage vaccines for the most vulnerable populations and issues of equity of treatment, in the new epidemic context.

It therefore appears reasonable to recommend the postponement of the 2nd dose to 6 weeks, for the two mRNA vaccines, in order to speed up the administration of the first dose to the most vulnerable people, in the order of priority previously established by HAS, subject to the following conditions:

1. the doses of mRNA vaccines available should be reserved as a priority for the vaccination of people aged 75 and over and then of people aged 65 to 74, starting with those with comorbidities (in which the risk of death linked to COVID 19 is higher [7]), according to the vaccination strategy established by the HAS
2. the rapid implementation of this modification of the vaccination schedule
3. the use of all available doses of the 2 mRNA vaccines and the maintenance of vaccine capacity including during potential periods of confinement.