The US Food and Drug Administration cleared a broad path for millions more Americans to receive Covid-19 vaccine booster shots, as the nation looks to bolster its defences and prevent another virus surge.
The agency said on Wednesday that Moderna vaccine recipients 65 and over can receive a third shot, as can adults 18 and up who are at high risk of severe Covid or with frequent institutional or occupational exposure to the virus that causes the disease.
In addition, all Johnson & Johnson recipients 18 and older are eligible for a booster shot at least two months after receiving their first dose.
The agency also allowed each of the available Covid vaccines to be used as a booster dose for eligible people following completion of a primary vaccination.
The moves will mean the US has a bigger toolkit to try to limit a potential winter virus rebound.
The summer’s Delta-variant fuelled surge in infections helped to increase urgency to make boosters available, and health officials across the US are eager to forestall a rebound in cases that could overwhelm hospitals and disrupt work and school this winter.
The clearances came after a panel of expert advisers to the FDA unanimously backed the Moderna and Johnson & Johnson booster regimens in two days of meetings last week.
Regulators have now signed off on boosters for all three coronavirus vaccines available in the US.
Last month, the FDA said people 65 and over and others who are at heightened risk of severe Covid-19 were eligible for a booster dose of the vaccine developed by Pfizer and BioNTech.
The Moderna booster shot authorised by the FDA is half the dose that is given in the initial two-shot series, and it should be given at least six months after the initial inoculation, regulators said.
The FDA said that a single booster dose of the Pfizer vaccine may be given at least six months after completing the primary series to people 18 to 64 with frequent institutional or occupational exposure to the coronavirus.
In permitting mixing vaccines, the FDA is allowing Johnson & Johnson recipients to receive an additional dose of any cleared vaccine after two months.
Likewise, recipients of Moderna and Pfizer who are eligible for a booster would receive their booster, including Johnson & Johnson’s shot, at least six months after their initial immunisation regimen.
Before the Moderna and Johnson & Johnson booster shots can be administered, the Centres for Disease Control and Prevention’s advisory panel on immunisation practices will discuss further recommendations about who should receive them on Thursday.
The next big milestone for the US immunisation effort looms next week, when the FDA advisory panel is expected to consider Pfizer’s proposed vaccine for children ages 5 to 11.
If authorised, it could be introduced to paediatrician offices and pharmacies as soon as next month.