Coronavirus vaccine (illustrative)
Coronavirus vaccine (illustrative)Reuters

The US Centers for Disease Control and Prevention (CDC) has authorized a fourth coronavirus vaccine for individuals who are moderately or severely compromised.

In August, CDC authorized a third dose for those 18 and above who are immunocompromised.

The fourth dose is not a "booster" but is necessary because immunocompromised individuals may not have experienced a complete immune response from the first doses, CNN added. Research has shown that a third dose improves antibody response to the vaccine in certain immunocompromised individuals.

The site quoted a study from John Hopkins University which showed that vaccinated immunocompromised individuals are 485 times more likely to be hospitalized or die from COVID-19 than other vaccinated individuals.

The CDC also said that small studies showed that among vaccinated individuals, the immunocompromised accounted for approximately 44% of breakthrough cases requiring hospitalization. They are also more likely to transmit the virus to those who are in close contact with them.

The CDC does not have a recommendation at this time regarding the fourth dose, CNN said, adding that CDC recommends such individuals consult with their doctors to determine if a fourth dose is warranted.