WASHINGTON — A committee of United States (US) health experts on Thursday (Sept 23) declined to approve Pfizer booster shots for individuals at high risk of Covid exposure due to their jobs, despite authorization from a different agency just the night before.

The decision has contributed to growing confusion about the campaign for booster doses in the United States, which the administration of President Joe Biden announced in mid-August but has since lost momentum.

The Centres for Disease Control and Prevention (CDC) committee voted Thursday to recommend a third dose of Pfizer's vaccine for people over age 65 and for those with underlying conditions who are at risk of developing a severe case of Covid.

CDC chief Rochelle Walensky has yet to sign off on the recommendations but is expected to give them the green light.

The Food and Drug Administration (FDA) on Wednesday, however, authorized the third Pfizer doses for a broader swath of the American public, including those at high risk of Covid-19 exposure due to their jobs or other circumstances, such as teachers, grocery store employees, health care workers and prison inmates.

But the CDC committee voted nine to six against including that category.

The hours-long debate left several experts torn, as the scientific community has failed to come to a consensus about whether a coronavirus vaccine booster shot is necessary at this time.

"It's too soon," said Dr Beth Bell, a physician and a member of the CDC committee.

"In my opinion, there's little marginal benefit to making this booster dose available at this time," said Dr Bell, a clinical professor in the department of global health at the University of Washington.

Some have pointed to the risk of myocarditis, an inflammation of the heart muscle, in young men as a cause for concern with a widely available third jab.

And in addition to worries about the complexities of administering third doses -- as a vocal minority of Americans have still refused to get vaccinated at all -- some experts also have concerns about the lack of data on the efficacy and safety of adding another shot to the Pfizer vaccine regimen.

The original two doses are still proving successful at keeping the vast majority of their recipients out of the hospital with coronavirus, anyway, they say.

Data does suggest, however, that the vaccine's efficacy against infection does significantly decline in older people over time.

About 13 million people aged 65 and older in the United States received the Pfizer vaccine more than six months ago and would now be eligible for a booster shot.

The Biden administration had originally planned on a mass campaign to administer third doses to all recipients of both the Pfizer and Modern Covid vaccines, starting Sept 20.

But experts at the FDA rejected that plan last week. AFP