The EU’s drug regulator has said people with severely weakened immune systems should be given a third dose of either the Pfizer-BioNTech or the Moderna vaccine at least 28 days after their second shot.
“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,” the European Medicines Agency said.
It also announced that a booster dose of Pfizer-BioNTech’s Covid-19 vaccine “may be considered at least six months after the second dose for people aged 18 years and older” with normal immune systems.
“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,” it said.
Several EU member states have already pre-empted the guidance and launched their own booster campaigns, although they vary widely over who is eligible.
On booster doses, the EMA said the “risk of inflammatory heart conditions or other very rare side effects after a booster is not known and is being carefully monitored.”
Rare cases of myocarditis, an inflammation of the heart muscle, have been reported in people who have taken the Pfizer vaccine, particularly in young men.
The US, UK and Israel have approved the use of Pfizer boosters, although only the latter is using them across the whole population.