Too Many Boosters Could Weaken Immune Response

Bloomberg Law confirmed on January 11, 2022, European Medicine Agency (EMA) regulators warned that frequent COVID-19 vaccinations could adversely affect the human immune response.

Boosters "can be done once, or maybe twice, but it's not something that we can think should be repeated constantly," Marco Cavaleri, the EMA head of biological health threats and vaccines strategy, said at a recent press briefing.

"We need to think about how we can transition from the current pandemic setting to a more endemic setting."

This EMA advice follows different tactics/advice announced by Israel, the United Kingdom (U.K.), and the World Health Organization, which stated on January 11, 2022, 'a vaccination strategy based on repeated booster doses of the original vaccine composition is unlikely to be appropriate or sustainable.'

In December 2021, Israel became the first country to administer a second booster, or fourth mRNA vaccination, to Israelis over the age of 60.

However, the U.K. stated there is no need for a second booster.

The Joint Committee on Vaccination and Immunisation chair of COVID-19 immunization, Professor Wei Shen Lim, said in a media statement issued on January 7, 2022: 'The current data shows the booster dose continues to provide high levels of protection against severe disease, even for the most vulnerable older age groups.'

'For this reason, the committee has concluded there is no immediate need to introduce a second booster dose.'

In the U.S., the Food and Drug Administration recently amended the emergency use authorization for mRNA COVID-19 vaccines to shorten the time between completing a two-dose primary series of the vaccine and a booster dose to at least five months for individuals 18 years of age and older. 

Peter Marks, M.D., Ph.D., director of the FDA's Center for Biologics Evaluation and Research, commented in a media statement, "We encourage everyone to get vaccinated—it's never too late to get your COVID-19 vaccine or booster." 

The EMA currently authorizes five COVID-19 vaccines. 

Maryland-based Novavax Inc.'s Nuvaxovid vaccine was recently authorized for adults in Europe.

The EMA is a decentralized agency of the European Union located in Amsterdam. It began operating in 1995 and is responsible for the scientific evaluation, supervision, and safety monitoring of medicines in Europe.