Adults who receive a third dose of the Pfizer-BioNTech or Moderna COVID-19 vaccine are better protected against COVID-19 hospitalization than their peers who have received only two doses, and immunocompromised patients may benefit the most, the Centers for Disease Control and Prevention reports.
Investigators analyzed vaccine status of adults hospitalized for complications of a various viruses in a multistate healthcare network. They compared outcomes between vaccine-eligible adults who had not received a third vaccine dose and those who had received a third dose 7 or more days before the onset of their illness.
A third dose for patients with healthy immune systems provided 97% efficacy, compared to 82% for two doses, they found. In the immunocompromised group, three doses provided 88% protection, while two supplied only 69% protection.
The findings underscore the critical importance of immunocompromised adults obtaining a third mRNA vaccine dose on the recommended schedule: 28 or more days after the second dose, the authors wrote. Immunocompetent adults are advised to receive a third (booster) dose five months or more after the second dose.
The study was published Friday in the CDC’s Morbidity and Mortality Weekly Report.
