“Risky” to delay second vaccine against Covid in the UK: former FDA director

It is “very risky” to delay the second dose of Covid-19 vaccines because efficacy data were based on a specific dosing schedule, a former FDA director told CNBC on Thursday.

His comments came after the UK decided to administer second shots of the coronavirus vaccine 12 weeks after the first dose, in line with what vaccine producers recommend. Germany is reportedly considering a similar move, while Denmark approved a six-week difference between doses.

The two vaccines approved for use in the UK require two doses.

The American pharmaceutical company Pfizer and the German biotechnology company BioNTech recommended that the second dose of their vaccine be administered 21 days after the first. British-Swedish pharmaceutical company AstraZeneca said the vaccine it developed in conjunction with Oxford requires two doses to be administered one month apart. The UK initially said it would follow this timetable.

Any decision to alter dosing schedules should be based on data, said Norman Baylor, former director of the U.S. Food and Drug Administration’s vaccine research and review office.

“It is very risky to try to expand [the gap between two doses] or give it a dose if there is no data, “he told CNBC’s” Street Signs Asia “on Thursday.

“I understand some of the reasons for doing so, but again, it’s not really based on data,” said Baylor, who is also president and CEO of Biologics Consulting. “It’s a very risky business because if it fails, it’s in a worse state.”

The controversial decision by the UK came as the country continues to face a new strain of coronavirus that is spreading faster, although there is no evidence that it is more serious or fatal. 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.

Delaying the second dose of the vaccine means more people can receive the first dose, but Baylor said it would be ideal to follow the dosing regimen of vaccine efficacy studies.

“If you don’t have the data, you risk it,” he said. “That’s the key point, the risk you take.”