The European Medicines Agency (EMA) has granted approval for a third dose of the Pfizer and Moderna COVID-19 vaccines, specifically for individuals with weakened immune systems. This decision comes in response to data indicating that an additional dose can significantly boost antibody production in this vulnerable population, potentially offering increased protection against the virus.
The recommendation stipulates that the third dose should be administered at least 28 days following the second dose in immunocompromised individuals. Studies have demonstrated that this additional dose enhances the body's ability to produce antibodies against COVID-19. While direct evidence confirming that this increased antibody production directly translates to protection against COVID-19 is still emerging, the EMA anticipates that the additional doses will bolster protection in at least some patients. The agency will continue to monitor emerging data on the effectiveness of this approach.
Booster Doses for General Population
It is crucial to distinguish between third doses for immunocompromised individuals and booster doses for the general population with normal immune systems. For the latter group, studies have indicated that antibody levels increase when a booster dose is administered approximately 6 months after the second dose, particularly in individuals aged 18 to 55 years.
Based on these findings, the Committee for Medicinal Products for Human Use (CHMP) concluded that booster doses can be considered at least 6 months after the second dose for individuals aged 18 years and older. However, the EMA emphasizes that national public health authorities retain the prerogative to issue official recommendations on the use of booster doses, taking into account new efficacy data and limited safety data.
Ongoing Monitoring
The EMA is committed to continuously evaluating all available data on the safety and effectiveness of COVID-19 vaccines. Of particular interest is the risk of inflammatory heart disease or other very rare side effects following a booster dose, which is being carefully monitored. The committee is also currently assessing data to support a booster dose for Spikevax (Moderna's vaccine) and will communicate the outcome of this evaluation upon completion.
