Covid-19 vaccines updates

Scientific advisers to the US Food and Drug Administration have voted overwhelmingly not to recommend approving Pfizer’s application to offer a third shot of its Covid-19 vaccine, dealing a serious blow to the Biden administration’s plans to launch a wide-ranging booster programme.

Members of the regulator’s vaccine advisory committee voted 16-2 on Friday against endorsing a booster of the BioNTech/Pfizer vaccine for Americans aged 16 or older.

But with several members having warned about the potential safety risks for younger recipients, FDA officials said they could reword the question to authorise boosters for a narrower part of the population, for example by limiting it only to older people.

Even if the FDA approves a third shot for older people it will be a significant setback for Joe Biden, the US president, who publicly backed a wide-ranging booster programme last month. Administration officials have supported the plan as a way to bring down high infection rates in the US.

While the Biden administration had announced plans to launch a booster programme next week, several members of the committee expressed doubt over whether there was enough data to give the go-ahead. While the FDA retains the final say over whether to approve the application, it will have to ignore the recommendations of the independent panel.

Several members said they were concerned about approving a booster dose for everyone aged 16 and over, given reports of rare cases of heart problems suffered by young people following the two-dose regimen.

“Given the risk of breakthrough infection in that younger population is much lower than it is in other parts of the population, recommending a third dose for younger people is just not something I’d be comfortable with at this point,” Melinda Wharton, a senior official at the Centers for Disease Control and Prevention and member of the committee, said.

Hayley Gans, professor for paediatric infectious diseases at Stanford University, said: “I am struck by the FDA asking us to look at the totality of evidence when there’s several key points I think that we’re lacking right now. One of them is the very strong safety data that we could have actually with all the third doses that have been given.”

Paul Offit, director of the Vaccine Education Center in Philadelphia, said: “While I would probably support a three-dose recommendation for those over 60 or 65, I really have trouble supporting this as written for people greater than or equal to 16.”

Pfizer told the committee earlier that boosters were needed to ensure the US did not experience a fresh wave of serious disease in coming months. Earlier this week Pfizer and Moderna both released data suggesting the effectiveness of their messenger-RNA vaccines can decline within months after a second shot.

As the FDA committee discussed the issue, the CDC released results from a study showing the efficacy of the Pfizer vaccine appeared to drop more steeply over time than jabs made by either Moderna or Johnson & Johnson.

The study, which analysed 3,689 people in 18 US states over the summer, found Moderna’s vaccine was 93 per cent effective at stopping hospitalisation with Covid-19 for people with functioning immune systems in the first four months after the course had been completed, and 92 per cent effective after that. The BioNTech/Pfizer vaccine was 91 per cent effective in the first four months, but only 77 per cent effective after that.

“There is a clear erosion of vaccine protection over time against Covid-19, and emerging data indicates a loss of protection against hospitalisation,” William Gruber, senior vice-president of vaccine clinical R&D for Pfizer, told the committee, adding that “the time to restore protection with a safe and effective booster dose . . . is now”.

Sara Oliver, a scientist at the CDC’s division of viral diseases, noted that while protection against infection has decreased in recent months, it was unclear whether it was because of a natural erosion of protection over time or because of the more contagious Delta variant.

Data from Israel show severe Covid cases began to decline sharply about 10 days after the booster programme started. Covid cases there jumped more than 10-fold from early July to August, with 60 per cent of cases in fully vaccinated people, data from the country showed.

“If we had not started booster doses at the end of July we would have come to the capacity of the Israel hospitalisation capability and probably gone beyond it,” Sharon Elroy-Preiss, director of public health services at Israel’s health ministry, told the panel on Friday.

Pfizer had sought to offer people aged 16 and older a booster of its two-dose mRNA jab at least six months after receiving the second shot. US regulators could choose to limit the availability of booster doses to certain age groups, such as over-65s.

The FDA has already authorised booster shots of mRNA vaccines for people with weakened immune systems. But allowing booster shots more broadly is controversial, both because of the limited data available about the vaccines’ long-term effectiveness, and because many countries are still struggling to secure initial supplies.

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, told the committee on Friday that it should focus “on the science related to the application under consideration today, and not on operational issues related to a booster campaign or on issues related to global vaccine equity”.

In a report published on Wednesday, FDA staff said the data were not conclusive on whether the vaccine’s ability to stop symptomatic infection declined significantly over time, a sign of internal frictions within the regulator about whether boosters were needed.

Others argue that US regulators should act quickly to stem the recent rise in coronavirus cases. Ali Mokdad, professor of global health at University of Washington, said: “We need to get a booster for everyone and to move on. Once we have boosters out then we can donate vaccines.”

In an open letter published on Thursday ahead of the FDA meeting, Pfizer’s chief executive Albert Bourla said allowing people in rich countries to get boosters would not divert supplies from those in need: “If the data demonstrates their need, safety and efficacy then they should be approved.”

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