COVID-19 Vaccination Effectiveness Against Infection or Death in a National U.S. Health Care System : A Target Trial Emulation Study.
George N IoannouEmily R LockeAnn M O'HareAmy S B BohnertEdward J BoykoDenise M HynesKristin BerryPublished in: Annals of internal medicine (2021)
U.S. Department of Veterans Affairs.