Individuals having some health conditions that make them moderately or severely immunocompromised may be offered a fourth mRNA COVID-19 vaccine jab, suggest updated guidelines from the US Centers for Disease Control and Prevention.

The agency had authorized a third vaccine dose for some immunocompromised people aged 18 years and above in August. It stated that a third dose, rather than a booster, was required as a complete immune response may not have been generated in the immunocompromised individuals from the first two doses.

A fourth vaccine dose would be given at least six months after the third mRNA vaccine shot. The agency does not have a recommendation about the fourth dose at present and says that people should talk to their doctors to see if it is required… (CNN, October 27, 2021)