A pair of new studies detail COVID-19 vaccine effectiveness, one showing 85% protection against hospitalization and the other describing waning efficacy for three vaccine types against infection and death caused by the highly transmissible Delta (B1617.2) variant among US veterans.84% of hospitalizations in unvaccinatedThe first study, published yesterday in JAMA, was led by researchers from the Centers for Disease Control and Prevention (CDC) COVID-19 Response Team.It involved 4,513 hospitalized coronavirus patients at 21 sites in 18 US states from Mar 11 to Aug 15, 2021, with a 28-day follow-up period.
The Delta variant became the predominant US strain in early July.Of the 4,513 patients, 1,983 were diagnosed as having COVID-19, and 2,530