Pharmaceutical giant Pfizer has asked health regulators in the United States to authorise booster jabs of its COVID-19 vaccine for everyone aged 18 and older, amid concerns that coronavirus infections could rise again in the coming winter months in the US.

Older Americans and those more vulnerable to infections are already eligible for a third booster jab in the US.

On Tuesday, Pfizer-BioNTech asked the US Food and Drug Administration (FDA) to make all adults in the country eligible.

The request comes amid concerns that COVID-19 infections could go on the rise again as the holiday season and colder weather typically bring more people indoors for large gatherings of friends and family.

According to the US Centers for Disease Control and Prevention (CDC), new coronavirus infections, hospitalisations and deaths have been on the decline in recent weeks across the country. But a sizeable portion of the US population remains unvaccinated.

The US has already launched a campaign to vaccinate children aged five to 11 [Matt Mills McKnight/Reuters]
The CDC’s latest figures show 70 percent of US adults are fully vaccinated and about 21.5 million booster doses have been administered to fully vaccinated people. The US also recently authorised the Pfizer vaccine to children between the ages of five and 11.

The administration of President Joe Biden had originally envisioned boosters for all adults but faced a stinging setback in September when the FDA’s scientific advisers rejected extra Pfizer doses for everyone.

The panel was not convinced that young, healthy people needed another dose, particularly when most of the world’s population remains unvaccinated.

Pfizer said it is submitting early results of a booster study in 10,000 people to make its case that it is time to expand the booster campaign in the US.

The study concluded that a booster could restore protection against symptomatic infection to nearly 96 percent, even as the extra-contagious Delta variant was surging. Side effects were similar to those seen with the company’s first two shots.

The US has authorised three vaccines and boosters in the US: Pfizer-BioNTech, Moderna and Johnson & Johnson.

Pfizer says it is submitting early results of a booster study in 10,000 people to make its case that it is time to expand the booster campaign in the US [Emily Elconin/Reuters]
Under the current rules, people who initially received Pfizer or Moderna jabs are eligible for a booster six months later if they are 65 or older, or are at high risk of contracting COVID-19 because of underlying health problems or their job or living conditions.

Because the single-dose Johnson & Johnson vaccine has not proven as effective as its two-dose competitors, any Johnson & Johnson recipient can get a booster at least two months later.

Under this policy, about two out of every three vaccinated adults are expected to qualify within the next few months.

The US has also cleared people to get a booster jab of a different company’s vaccine, what is often called “mixing and matching“.

If the FDA authorises Pfizer boosters for all adults, the CDC will then make recommendations for how to use them.