The United States on Wednesday gave authorisation for the use of booster shots of the Pfizer-BioNTech Covid-19 vaccine for high-risk adults and those aged 65 and above.

The third shot will be administered at least six months after the second dose, the Food and Drug Administration said.

The citizens eligible for booster shots of the vaccine will include healthcare workers, teachers, those working in grocery stores, the ones lodged in prisons and occupants of homeless shelters, the agency said.

The Food and Drug Administration’s Acting Commissioner Janet Woodcock said new data about the safety and effectiveness of the Covid-19 vaccines was emerging every day.

She added: “As we learn more about the safety and effectiveness of Covid-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed.”

Last week, an independent panel of experts had voted for authorising booster shots for certain groups, AFP reported. However, it rejected the US government’s plan to approve the booster doses for all citizens aged 16 and above.

Even though the Food and Drug Administration has authorised booster shots, the Centers for Disease Control and Prevention has to give the go ahead for the doses to administered, CNN reported. The public health agency will hold a meeting about the matter on Thursday.

The rollout of booster shots has become a subject of international debate with the World Health Organization repeatedly highlighting unequal access to vaccines.

On September 8, WHO chief Tedros Adhanon Ghebreyesus had called for a moratorium on administering booster shots till at least the end of the year to allow every country to vaccinate at least 40% of its population.

The coronavirus has infected over 23 crore people in the world and caused more than 47 lakh deaths globally since the pandemic broke out in December 2019, according to Johns Hopkins University.