The clinical implications of COVID-19 have changed since SARS-CoV-2 first emerged in
humans. The current high levels of population immunity, due to prior infection and/or …

Background Immunocompromised individuals are not optimally protected by COVID-19
vaccines and potentially require additional preventive interventions to mitigate the risk of …

Introduction Despite representing only 3% of the US population, immunocompromised (IC)
individuals account for nearly half of the COVID-19 breakthrough hospitalizations. IC …

Early Estimates of Bivalent mRNA Vaccine Effectiveness in Preventing COVID-19–Associated
Emergency Department or Urgent Care Encounters and Hospitalizations Among …

Among adults aged≥ 18 years without immunocompromising conditions, bivalent booster
vaccine effectiveness (VE) against COVID-19–associated hospitalization declined from 62 …

The bivalent (original and Omicron BA. 4/BA. 5) mRNA-1273 COVID-19 vaccine was
authorized to offer broader protection against COVID-19. We conducted a matched cohort …

There is a public health need to understand how different frequencies of COVID-19 booster
vaccines may mitigate the risk of severe COVID-19, while accounting for waning of …

Background Immunocompromised patients may be at higher risk of mortality if hospitalised
with Coronavirus Disease 2019 (COVID-19) compared with immunocompetent patients …

Abstract In September 2023, CDC's Advisory Committee on Immunization Practices
recommended updated 2023–2024 (monovalent XBB. 1.5) COVID-19 vaccination for all …

In this study of vaccine effectiveness of the US-authorized bivalent mRNA booster
formulations, bivalent boosters provided significant additional protection against …