The agency said earlier it was assessing the need for boosters for those who received the Moderna shot. Recent studies appear to show that efficacy of the American-German vaccine loses efficacy more quickly than Moderna’s, possibly as it uses a weaker mRNA formulation, though both continue to provide adequate protection against serious cases requiring hospitalization.

All 27 EU member states will be free to recommend or refrain from recommending which of their populations will be eligible for the third dose. In any case, the composition of this dose will be identical to the first two. Pfizer and BioNTech are currently working on an updated vaccine that would take into consideration several strains of the coronavirus.

Some member states, including France, Germany and Belgium – if somewhat under the radar – started giving third doses to older people and those with weakened immune systems during September, with the Czech Republic and Hungary offering them to all adults.

Explaining its recommendation, the EMA said its data showed an increase in antibody levels in adults aged 18 to 55 with normal immune systems who received a third dose of Pfizer/BionTech’s Comirnaty.  It did not say how long this protection lasted. As to dosing, the health authority said that people with “severely weakened” immune systems could receive an extra dose of the mRNA vaccines as early as 28 days after the second dose. Others should wait at least six months.

The EMA added that it believes a third inoculation could increase protection against Covid in at least some patients.  In particular, it pointed to studies showing that a booster with either of the two mRNA vaccines could increase the ability to produce antibodies in organ transplant recipients.

The European agency’s decision unexpectedly puts the 27-member bloc ahead of the US, where the Food and Drug Administration (FDA) in a controversial move last month followed the advice of its advisory panel not to authorize a booster for the population generally.

Currently, a third dose is officially limited to US residents over 65, the immunocompromised and certain professions at high risk of contracting the virus. Some observers, however, believe it is only a question of time until it is available to anyone who wants it. Some Americans already are getting a third shot as not all centers or physicians demand identification.

The Pfizer/BioNTech vaccine is the only one to be fully approved in the US and consequently the only one authorized for booster shots. Along with the FDA, many scientific advisory boards, including Germany’s standing committee on inoculation, STIKO, have been reluctant to recommend boosters, while acknowledging that this might be advised by next year. For those getting a third dose now, Germany for the present is recommending Comirnaty.

Up to now, the World Health Organization (WHO) has been strictly opposed to third doses of Covid vaccines for the First World until more of the Third World has received the first. The WHO’s director general, Tedros Ghebreyesus, has called for a moratorium on coronavirus vaccine booster shots for people who are not immunocompromised, until at least the end of this year.

Author: Dede Williams, Freelance Journalist