After evaluating data that showed a rise in antibody levels following a booster dose of Comirnaty around six months after the second dose, the CHMP concluded boosters may be administered on this basis for people aged 18+.
The advice will be considered by each of the 27 EU member states who will make their own policy on whether to administer booster shots: weighing up the advantages and risks of boosters in different population groups. While governments are keen to revitalise economies and fight the spread of the Delta variant, there are limited data on the effectiveness of boosters across the general population.
“At national level, public health bodies may issue official recommendations on the use of booster doses, taking into account emerging effectiveness data and the limited safety data," says the agency.
In the US, a Pfizer/BioNTech booster shot has been authorized solely for certain populations: such as those aged 65+ or aged 18+ and at high risk. The booster shot is to be administered at least six months after the second dose.
"The risk of inflammatory heart conditions or other very rare side effects after a booster is not known and is being carefully monitored.
"As for all medicines, EMA will continue to look at all data on the safety and effectiveness of the vaccine.”
The CHMP is still in the process of evaluating data for a Spikevax (Moderna) booster shot.
Weakened immune systems
Meanwhile, the CHMP says that an extra dose of either Comirnaty or Spikevax may be administered to people with severely weakened immune systems, at least 28 days after the second dose.
The recommendation comes after studies showed that an extra dose of these vaccines increased the ability to produce antibodies against the virus that causes COVID-19 in organ transplant patients with weakened immune systems.
"Although there is no direct evidence that the ability to produce antibodies in these patients protected against COVID-19, it is expected that the extra dose would increase protection at least in some patients. EMA will continue monitoring any data that emerges on its effectiveness," says the agency.