Giving a second injection six weeks after the first would allow at least 700,000 more people to be protected with a first shot 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.
Surging covid infections from the spread of a new virulent strain and supply issues have increased pressure on some governments to experiment with dosing regimens. The U.S. Centers for Disease Control and Prevention this week said that said follow-up doses could be given up to six weeks later.
The U.K. has already pushed the maximum wait time from three weeks to 12 weeks as Boris Johnson's government seeks to vaccinate 15 million people by Feb. 15. That strategy is now facing some resistance. A group of senior doctors called on England's chief medical officer to cut the gap between the first and second doses of the Pfizer Inc. and BioNTech vaccine by half, according to the BBC.
The British Medical Association on Saturday urged Chris Whitty, England's chief medical officer, to "urgently review the U.K.'s current position of second doses after 12 weeks," the AP reported. The association said there was "growing concern from the medical profession regarding the delay of the second dose of the Pfizer-BioNTech vaccine as Britain's strategy has become increasingly isolated from many other countries."
"No other nation has adopted the U.K.'s approach," Dr. Chaand Nagpaul, chairman of the BMA council, told the BBC, the AP said. He noted the World Health Organization recommended that the second Pfizer vaccine could be given six weeks after the first but only in "exceptional circumstances."
"I do understand the trade-off and the rationale, but if that was the right thing to do then we would see other nations following suit," Nagpaul said, according to the AP. The BBC cited a private letter sent from the association to Whitty.
The government's Joint Committee on Vaccination and Immunisation says unpublished data shows that the Oxford-AstraZeneca vaccine is still effective with doses 12 weeks apart, but Pfizer has said it has tested its vaccine's efficacy only when the two doses were given up to 21 days apart, the BBC said.
The French health authority said it based its new recommendation on models carried out by France's Institut Pasteur and U.S. and Canadian studies.
In its recommendation released on Jan. 21, the U.S. CDC said that if it's impossible to get the follow-up shot on time, people may schedule it as long as six weeks, or 42 days, after their initial dose. There is "limited data on efficacy" of the Pfizer and Moderna vaccines beyond that interval, according to the guidance, but if the second dose is administered later, "there is no need to restart the series."
Both those vaccines are authorized for emergency use in the U.S. and were cleared based on trials of two doses weeks apart. A grace period of four days ahead of schedule would be considered valid for a second dose, but people shouldn't receive the second dose earlier than that.
Published : January 24, 2021
By : Syndication Washington Post, Bloomberg · Tara Patel, Suzy Waite