The US has authorised Covid-19 booster doses that target the highly contagious Omicron variant in the hopes of preventing another winter surge in cases.
The move on Wednesday by the Food and Drug Administration (FDA) to approve the shots from Pfizer and Moderna means they could become available to the public within days.
The Centers for Disease Control and Prevention (CDC) must now recommend who gets priority to receive the additional booster shots.
Eligibility will depend on age, and when a patient’s previous doses were administered, according to the FDA.
The updated boosters are only for those who have already received at least one dose of the original Covid vaccine.
The Biden administration had purchased around 170 million doses, and Pfizer has said it can begin shipping up to 15 million by next week.
The question remains whether Americans who have taken previous vaccines will be prepared to roll up their sleeves again.
Around 68 per cent of the US population is fully vaccinated, which the CDC defines as having had at least two shots, while 79.7 per cent have had one dose.
FDA commissioner Robert Califf told a press conference on Wednesday the boosters represented an “opportunity to get ahead of the next wave”.
He said patients would have to wait at least two months after receiving their previous dose.
FDA vaccine chief Dr Peter Marks earlier told the Associated Press he would be “at the front of the line” for the new shots.
Studies published by the CDC in July show that receiving a third and fourth vaccine dose offered “substantial additional protection” from moderate and severe disease.
Omicron is now the dominant strain in the United States, and much of the world, as the variant has proven adept at bypassing the older vaccines and immunity from previous infection.
Figures from the CDC show that Omicron, also known as BA.5, accounts for approximately 89 per cent of cases in the US.
Associated Press contributed to this report
