‘Risky’ of delaying second Covid vaccine in UK: former FDA director

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 a second injection of the coronavirus vaccine 12 weeks after the first dose, breaking with what is recommended by vaccine producers. Germany is reportedly considering a similar move, while Denmark has approved a six-week gap between doses.

Vaccines approved for use in the UK both require two doses.

US pharmaceutical company Pfizer and German biotech company BioNTech have recommended that the second dose of their vaccine be given 21 days after the first. Anglo-Swedish pharmaceutical company AstraZeneca said the vaccine it co-developed with Oxford requires two doses which should be given one month apart. The UK initially said it would follow that schedule.

Any decision to change dosing schedules should be based on data, said Norman Baylor, former director of the U.S. Food and Drug Administration’s Office of Vaccine Research and Review.

“It is very risky to try to extend [the gap between two doses] or give a dose in the absence of data, “he told CNBC” Street Signs Asia on Thursday.

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

The UK’s controversial move came as the country continues to fight a new strain of the coronavirus that is spreading faster, although there is no evidence that it is more serious or deadly. Some 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 their first dose, but Baylor said it would be ideal to follow the dosing regimen of the vaccine’s efficacy studies.

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