CDC Report Addresses Vaccine Efficacy in Immunocompromised Persons

November 5, 2021

In this week’s Morbidity and Mortality Weekly Report (MMWR), the CDC addressed COVID-19 vaccine efficacy in immunocompromised persons. Studies and clinical data suggest that immunocompromised persons who receive COVID-19 vaccines may not develop robust antibodies, and may not be protected against severe COVID-19 like immunocompetent persons who have been vaccinated. In a retrospective analysis of 20,000 hospitalized COVID cases, immunocompromised persons given two doses of an mRNA vaccine mounted 77% efficacy against COVID-19 hospitalization. Patients with rheumatic and inflammatory disorders were included in this cohort. MRNA vaccines in immunocompetent adults (as part of the control group) demonstrated 90% efficacy. “This difference persisted irrespective of mRNA vaccine product, age group, and timing of hospitalization relative to SARS-CoV-2.” Use of immunosuppressive therapies was not collected for data analysis.

The median age of immunocompetent and immunocompromised patients was 68 years and 70 years, respectively. “Among immunocompetent patients, 42% had received the Moderna vaccine and 58% had received the Pfizer-BioNTech vaccine, and among immunocompromised patients, 41% and 59% had received Moderna and Pfizer-BioNTech vaccines, respectively.” Among immunocompetent patients, the median time between receiving the second dose of the Moderna vaccine and hospital admission was 89 days; this increased to 90 days for Pfizer vaccine recipients. Among immunocompromised patients, intervals were 89 days for both Moderna and Pfizer vaccine recipients.