It is “too risky” to delay the second dose of Covid-19 vaccines because the efficacy data was based on a specific dosing schedule, a former FDA director told CNBC on Thursday.
His comments were made after the UK’s decision to administer a second injection of the coronavirus vaccine 12 weeks after the first dose, at odds with what is recommended by vaccine producers. Germany is considering a similar change, while Denmark has approved a six-week interval between doses.
Vaccines approved for use in the UK require two doses.
American pharmaceutical Pfizer and German biotechnology company BioNTech recommended that the second dose of their vaccine be given 21 days after the first. Swedish-British pharmaceutical company AstraZeneca said that the vaccine that it co-developed with Oxford requires two doses that must be administered one month apart. The UK initially said it would follow that schedule.
It is a very risky undertaking because, if it fails, you will get worse.
Norman Baylor
Former FDA Director
Any decision to change dosing schedules should be based on data, said Norman Baylor, a former director of the vaccine research and review office of the U.S. Food and Drug Administration.
“It is very risky to try to extend [the gap between two doses] or give it a shot in the absence of data, “he told CNBC’s” Street Signs Asia “on Thursday.
“I understand some of the reasons for doing this, but again, it’s not really based on data,” said Baylor, who is also president and chief executive officer of Biologics Consulting. “It is a very risky undertaking because, if it fails, you will get worse.”
The UK’s controversial decision came as the country continues to fight a new strain of coronavirus that spreads faster, although there is no evidence that it is more serious or deadly. About 62,322 cases were reported on Wednesday, and more than 2.8 million people have tested positive for the virus so far, according to government data.
A nurse prepares the Oxford-AstraZeneca vaccine at Pontcae Medical Practice on January 4, 2021 in Merthyr Tydfil, Wales.
Matthew Horwood | Getty Images News | Getty Images
Delaying the second dose of the vaccine means that more people can receive their first dose, but Baylor said it would be ideal to follow the dosing regimen of the vaccine’s effectiveness studies.
“If you don’t have the data, you risk it there,” he said. “That is the key point, the risk that you take.”