(Bloomberg) -- France’s top health authority is recommending a doubling of the time between two vaccine shots as a way to stretch supplies and inoculate as many people as quickly as possible amid a resurgence in the spread of Covid-19.
Giving a second injection six weeks after the first would allow at least 700,000 more people to be protected during the first month, the country’s Haute Autorite de Sante said in a statement Saturday. The advice is for the vaccine made by Pfizer Inc. and BioNTech SE as well as another supplied by Moderna Inc., it said.
“The risk of a loss of efficacy appears limited” the health body said, noting that the regime recommended by the companies is for a lag of three or four weeks between shots, but that protection from the virus actually begins between 12 and 14 days after the first jab.
The goal is to protect the largest number of vulnerable people and prevent the heath system from becoming overwhelmed, it said.
The French advice follows guidance two days ago by the U.S. Centers for Disease Control and Prevention that said follow-up doses could be given up to six weeks later if it’s not feasible to get them in the recommended interval.
The need for these second doses at specified intervals is one layer of complication in vaccination campaigns that have rolled out across the globe. A new surge in infections and more virulent strains have increased pressure on countries to experiment with dosing regimens to get more people their first of two shots to provide initial protection.
Britain has said it would allow for second doses of some vaccines to be given as many as 12 weeks after the first, longer than the timing determined as optimal for both vaccines.
The French body said it based its recommendation on models carried out by France’s Institut Pasteur and U.S. and Canadian studies.
U.K. officials have said the data show the authorized vaccines provide considerable defense after a single dose, with the second shot important over the longer term. Both companies and the FDA have said it’s unclear how long protection from the first shot will last. Pfizer has said that the second dose of its Covid-19 vaccine should be delivered to individuals within the recommended 21-day period.