Observational study finds the effectiveness of mRNA vaccination against Covid-19 hospitalization was lower (77%) among immunocompromised adults than among immunocompetent adults (90%).

Effectiveness of 2-Dose Vaccination with mRNA COVID-19 Vaccines Against COVID-19–Associated Hospitalizations Among Immunocompromised Adults — Nine States, January–September 2021 – CDC Morbidity and Mortality Weekly Report

Related:

CDC Guidance: Immunocompromised may need a fourth Covid-19 shot.

Commentary on Twitter (thread – click for more)

New CDC study of mRNA #vaccination & disease in 89,000 ppl hospitalized w/#COVID19
– 69K had normal immune systems; 1/2 of them were 2-dose vaxed
– 20K had systs weakened by cancer or other illnesses, 25% of whom were unvaxed
– Vax was 90% effective in preventing severe…
MORE pic.twitter.com/w3RFCrQnLB

— Laurie Garrett (@Laurie_Garrett) November 2, 2021