Scientists at the United States’ FDA said on Tuesday that Moderna had not met all of the agency’s criteria to support the use of booster doses of its COVID-19 vaccine, possibly because the efficacy of the shot’s first two doses remained high, Reuters reported Tuesday.
In documents, FDA staff stated that data for Moderna’s vaccine showed that a booster does increase protective antibodies, but the difference in antibody levels before and after the shot was not large enough, especially in those whose levels remained high.
The documents were made public ahead of a meeting of the FDA’s outside expert advisers later this week to discuss booster doses of the vaccine.
This week, the US Food and Drug Administration will assess the efficacy of Moderna and Johnson & Johnson’s third dose of Covid vaccines.
CNBC reported that the FDA’s Vaccines and Related Biological Products Advisory Committee will meet on Thursday and Friday.
Earlier this month, the US Food and Drug Administration approved Covid booster shots of Pfizer and BioNTech’s vaccine for a wide range of Americans, including the elderly, adults with underlying medical conditions, and those who work or live in high-risk settings, such as health and grocery workers.
According to the most recent CDC data, more than 7 million Americans had received a booster dose as of Saturday.
“Even with delta, the current vaccines are holding up quite well as far as hospitalisation and severe disease are concerned,” said Norman Baylor, former director of the FDA’s vaccines office.
On Thursday, the FDA advisory panel will meet to discuss data on the safety and effectiveness of a Moderna booster shot in adults. According to the report, the committee will discuss J&J booster shots for adults on Friday.
The FDA’s final decision will be forwarded to the CDC and its vaccine advisory committee, who will then make their own determination.
The CDC’s next vaccine advisory meeting is scheduled for October 20-21, where the boosters are expected to be discussed.
According to the report, Moderna said last month that a third shot at half the dosage used for the first two jabs was safe and produced a stronger immune response than the second dose in its phase three clinical trial.
J&J said last month that a second dose of its single-shot vaccine was safe and increased protection against symptomatic infection from around 70% to 94% when given two months after the first dose in the United States.
Meanwhile, late Monday, experts from a World Health Organization (WHO) panel recommended that Covid-19 booster shots be given to moderately and severely immunocompromised people, changing the WHO’s stance on the third dose.
The WHO had previously called for a global moratorium on Covid-19 booster doses, with the goal of achieving a more equitable distribution of vaccines so that every country can vaccinate at least 40% of its population.
Last week, the World Health Organization announced a plan to vaccinate 40% of each country’s population against Covid-19 by the end of 2021, and 70% by mid-2022.