Tenforde MW, Self WH, Adams K, et al. - Researchers examined if prior vaccination with mRNA COVID-19 vaccines—mRNA-1273 (Moderna) and BNT162b2 (Pfizer-BioNTech)—is associated with reduced COVID-19 hospitalization, and, among patients hospitalized with COVID-19, is associated with reduced disease severity.

• A case-control analysis of 4,513 hospitalized adults in 18 US states.

• Significantly less frequent vaccination with an mRNA COVID-19 vaccine was recorded among patients with COVID-19 relative to other conditions and among those with COVID-19 who progressed to death or mechanical ventilation than those with COVID-19 who did not have disease progression.

• Findings overall support that patients with vaccine breakthrough infections are at reduced risk of developing severe COVID-19 when compared with absence of vaccination.

• For full vaccination with an authorized or approved mRNA COVID-19 vaccine, hospitalization for a COVID-19 diagnosis vs an alternative diagnosis was associated with an adjusted odds ratio (aOR) of 0.15.

• Among adults hospitalized for COVID-19, full vaccination was linked with an aOR of 0.33 for progression to death or invasive mechanical ventilation.

• Both ORs were statistically significant.