The US Food and Drug Administration (FDA) has granted emergency use authorisation (EUA) for a booster dose of the Pfizer-BioNTech Covid-19 vaccine for children aged between 5 to 11 years at least five months after completion of the primary vaccine series.

On January 3, the FDA authorised on Tuesday the use of a single booster dose of the Pfizer-BioNTech Covid-19 vaccine for individuals aged between 12 to 15 years after completion of primary vaccination.

The FDA’s decision on Tuesday means anyone aged 5 years and above is now eligible for at least one booster dose, Xinhua news agency reported.

“While it has largely been the case that Covid-19 tends to be less severe in children than adults, the Omicron wave has seen more kids getting sick with the disease and being hospitalised, and children may also experience longer term effects, even following initially mild disease,” said FDA Commissioner, Robert Califf in a statement.

“The FDA is authorising the use of a single booster dose of the Pfizer-BioNTech Covid-19 vaccine for children aged between 5 to11 years to provide continued protection against Covid-19,” he added.

Since authorising the Pfizer-BioNTech Covid-19 vaccine for children aged up to 5 years in October 2021, emerging data suggest that vaccine effectiveness against Covid-19 wanes after the second dose of the vaccine in all authorised populations, said Peter Marks, Director of the FDA’s Center for Biologics Evaluation and Research.

The FDA said Tuesday’s decision is based on analysis of immune response data in a subset of children from the ongoing randomised placebo-controlled trial.

Antibody responses were evaluated in 67 study participants, who received a booster dose 7 to 9 months, after completing a two-dose primary series of the Pfizer-BioNTech Covid-19 vaccine.

The antibody level against the SARS-CoV-2 virus one month after the booster dose was increased compared to before the booster dose, according to the FDA.

The FDA has determined that the known and potential benefits of a single booster dose of the Pfizer-BioNTech Covid-19 vaccine for children aged between 5 to 11 years at least five months after completing a primary series outweigh its known and potential risks, and that a booster dose can help provide continued protection against Covid-19 in this and older age groups.

Pfizer requested this EUA at the end of April, citing company data which showed that a third vaccine dose raised Omicron-fighting antibodies by 36 times in this age group.