A third dose of Pfizer or Moderna's COVID-19 vaccine reduces the risk of hospitalization among people with weakened immune systems, according to a CDC report published the week of Jan. 28.
CDC researchers analyzed data on 2,952 adults admitted to 21 U.S. hospitals between Aug. 19 and Dec. 15, 2021. More than 1,800 adults in the analysis were immunocompromised.
Vaccines were 88 percent effective at preventing hospitalizations among immunocompromised people who had received a third dose, compared to 69 percent for those who only received two doses of an mRNA vaccine.
The study occurred when the delta variant was dominant in the U.S., but early evidence suggests a third mRNA vaccine dose strongly protects against severe illness from omicron, the CDC said.
Further research is needed to understand the level of protection third doses provide against omicron for different populations, including those who are immunocompromised.
View the full report here.