A CDC study in nursing homes showed that two doses of mRNA vaccines were 74.7% effective against infection early in the vaccination program but declined to 53.1% three months later as the Delta variant predominated. Federal regulators are likely to approve a Covid-19 booster shot for vaccinated adults starting at least six months after the previous dose rather than the eight-month gap they previously announced, a person familiar with the plans said, as the Biden administration steps up preparations for delivering boosters to the public. Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security, has pointedout that vaccines aren’t force fields — they don’t prevent infections. They train your immune system to respond quickly to infections and hopefully limit the number of cells that get infected. They work to limit infections to prevent severe disease, hopefully to keep people out of the hospital.
CSSE is reporting 38,204,085 positive cases in the U.S. and 632,151 deaths.