2023-2024 COVID-19 vaccine uptake among immunocompromised individuals in two US states

Uptake of COVID-19 vaccines has declined over time, however, little data exist describing uptake among the immunocompromised who remain at high risk of severe disease. We evaluated XBB COVID-19 vaccine uptake during the 2023-2024 season among immunocompromised persons who had previously received a COVID-19 vaccine in two large, diverse US states.

Using data from state vaccine registries linked to insurance claims, we conducted a retrospective cohort study among individuals ≥6 months of age living in California or Louisiana as of September 11, 2023 who (1) had continuous pharmacy and medical enrollment in an insurance plan reported by HealthVerity, (2) met the Centers for Disease Control and Prevention criteria for moderately or severely immunocompromised (HIV/AIDS or primary immunodeficiency, hematologic malignancy in the prior year, solid organ or bone marrow transplant in the prior two years, or use of immunosuppressive therapy in the prior 210 days), and (3) previously received at least one dose of COVID-19 vaccine. We calculated the cumulative incidence of 2023-2024 COVID-19 vaccine receipt through March 31, 2024, stratified by state, age group, and specific immunocompromising condition.

A total of 321,896 (median age 55 years; 57 % female) and 43,250 (median age 45 years; 64 % female) immunocompromised individuals met selection criteria in California and Louisiana, respectively. In both states, the most common immunocompromising category was the use of immunosuppressive therapy (78 % and 85 % of individuals in California and Louisiana, respectively). Only 21 % of individuals in California and 6 % of individuals in Louisiana received a 2023-2024 COVID-19 vaccine by March 31, 2024. Uptake was similar across immunocompromising conditions.

During the 2023-2024 respiratory virus season, COVID-19 vaccine uptake among the immunocompromised in these 2 states was low, with fewer than 21 % receiving a 2023-2024 dose. Enhanced efforts to increase COVID-19 vaccine uptake in this vulnerable population are needed.