Delaying the second dose of Covid-19 vaccines is “very risky” because efficacy data was based on a specific dosing schedule, a former FDA director told CNBC on Thursday.
His comments came after the UK’s decision to give second shots of the coronavirus vaccine 12 weeks after the first dose, in deviation from what is recommended by the vaccine manufacturers. Germany is reportedly considering a similar move, while Denmark has approved a six-week interval between doses.
The vaccines approved for use in the UK both require two doses.
The US pharmaceutical company Pfizer and the German biotechnology company BioNTech recommended giving the second dose of their vaccine 21 days after the first. British-Swedish pharmaceutical company AstraZeneca said the vaccine it co-developed with Oxford requires two doses to be administered one month apart. The UK initially said it would follow that schedule.
It is a very risky business because if it fails, you will be in worse shape.
Norman Baylor
Former FDA Director
Any decision to change dosing schedules should be based on data, said Norman Baylor, a former director of the United States Food and Drug Administration’s agency for vaccine research and evaluation.
“Trying to expand is very risky [the gap between two doses] or give a dose for lack of data, ”he told CNBC’s“ Street Signs Asia ”Thursday.
“I understand some of the rationale for doing this, but then again, it’s not really data-driven,” said Baylor, who is also president and chief executive officer of Biologics Consulting. “It’s a very risky business because if it doesn’t work out, you’re in worse shape.”
The UK’s controversial decision came as the country continues to grapple with a new strain of the coronavirus that is spreading faster, although there is no evidence that it is more serious or deadly. About 62,322 cases were reported Wednesday, and according to government data, more than 2.8 million people have tested positive for the virus to date.
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 will allow more people to get their first dose, but Baylor said it would be ideal to follow the dosing regimen of the vaccine efficacy studies.
“If you don’t have the data, you’re taking a risk there,” he said. “That’s the most important point, the risk you take.”