The EU’s drug regulator has expressed doubts about whether a second booster dose of the currently available COVID-19 vaccines would be a sustainable long-term approach.
“There is an emergency discussion around the possibility of giving a second booster dose with the same vaccine currently in use. Data has not yet been generated to support this approach,” Marco Cavaleri, the European Medicines Agency’s (EMA) head of vaccines strategy, told a media briefing.
He added later, “We would like to see this data before we can make any recommendation, but at the same time we are rather concerned about a strategy that [involves] repeated vaccinations within a short term.”
An additional vaccine booster shot “could be considered as part of a contingency plan,” but “repeated vaccinations within short intervals will not represent a sustainable long term strategy,” according to Cavaleri.
Concerns Over Immune Response
When asked to expand on his statements, Cavaleri said that for a hypothetical approach of giving vaccine booster shots frequently, such as every four months, “we will end up potentially having problems with immune response and immune response may end up not being as good as we would like it to be, so we should be careful in not overloading the immune system with repeated immunization.”
He also noted that continuous administration of boosters can also lead to fatigue in the population.
“It will be much better to start thinking about an administration of boosters that is more spaced in time,” Cavaleri said.
The EMA is in conversation with vaccine developers in case there’s a need to update the current vaccines, according to Cavaleri. But he said any change “would have to be coordinated globally.”