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.