By Ethan Covey
Adults who have received three doses of a COVID-19 vaccine are 94% less likely to require invasive mechanical ventilation (IMV) or die due to COVID-19 infection than unvaccinated individuals.
Vaccination provides strong protection against the most severe disease outcomes (MMWR Morb Mortal Wkly Rep 2022;71:459-465).
The study used surveillance data from the Influenza and Other Viruses in the Acutely Ill (IVY) Network, from adults 18 years of age and older who were hospitalized at 21 medical centers in 18 states from March 11, 2021 through Jan. 24, 2022.
A total of 7,544 patients were included in the study, of whom 1,440 (19%) were COVID-19 case patients who suffered IMV, death or both, and 6,104 (81%) who served as uninfected controls.
The overall rate of messenger RNA (mRNA) vaccine effectiveness against COVID-19–associated IMV and in-hospital death was 90%. This included a rate of 88% among adults who received two COVID-19 vaccine doses, and 94% among those who received three doses. The effectiveness of three vaccine doses was also 94% when calculated specifically for those who were infected with the omicron variant. Protection was highest in adults without chronic medical conditions, at 98%.
“These findings reaffirm the lifesaving benefits of COVID-19 vaccines among adults, as well as the importance of staying up-to-date with COVID-19 vaccination, including a booster dose for eligible adolescents and adults,” said Mark W. Tenforde, MD, PhD, a medical officer with the CDC’s COVID-19 Emergency Response Team.
