The European medicines regulator said data showed a third dose of Moderna's COVID-19 vaccine led to a rise in antibody levels.
ADVERTISEMENTThe European Medicines Agency (EMA) said a third dose of Moderna's COVID-19 vaccine "may be considered" in people aged 18 and older.
The vaccine is usually given as two doses about four weeks apart in people aged 12 and older.
But the European regulator said data showed that a third dose given six to eight months after the second dose would lead to a rise in antibodies that protect against the coronavirus.
This booster shot is half of the dose typically given to adults, the agency said. Side effects of the booster shot were similar to those after the second dose.
"The risk of inflammatory heart conditions or other very rare side effects after a booster is being carefully monitored," EMA said, adding that they would continue to evaluate the vaccine's safety and effectiveness.
There have been very rare cases of heart inflammation reported mostly in young adults after the second jab of both mRNA coronavirus vaccines: Moderna and Pfizer.
A third booster shot of the Pfizer vaccine had already been approved for people aged 18 and older at least six months after the second dose.
EMA also recommended that an extra dose of the Moderna and Pfizer COVID-19 vaccines be given to people with weakened immune systems.
It is up to national public health bodies in Europe to issue the official recommendations following the European regulator's advice.
Moderna announced on Monday as well that its COVID-19 vaccine was safe and effective in children between the ages of six and 11.
The biotechnology company added that it would submit new data to global regulators soon.