The European Medicines Agency (EMA) has stated that a booster dose of the Pfizer/BioNTech and Moderna COVID-19 vaccines may be given to individuals whose immune systems are severely compromised, at least 28 days following the administration of the second dose.

The European drug regulator said that it has recommended a third vaccine dose after studies suggested that an additional dose of the two vaccines could enhance the ability to produce antibodies in organ transplant patients whose immune systems were weakened.

EMA would continue to look for data on the effectiveness of protection. It further drew a distinction between administering the third dose to people with compromised immune systems and those without. For individuals with normal immune systems, the agency stated that booster doses of Pfizer/BioNTech vaccine may be considered at least 6 months following the second dose for those aged 18 and above. The EMA is looking into data to support a booster shot of the Moderna vaccine for people with normal immune systems… (CNN, October 4, 2021)