Single shot of two-dose COVID vaccine can prevent serious illness and death

A first look at the potential effect of stretching limited COVID-19 vaccine supplies has found that just one dose of the Pfizer-BioNTech vaccine was 60% to 70% effective at preventing symptomatic disease in people age 70 and older.

That protection started 10 to 13 days after receiving the shot and lasted for more than six weeks, according to a preliminary report released Tuesday by Public Health England…

The study authors found that a month after Brits 80 and over got a first dose of the Pfizer-BioNTech vaccine, they were 43% less likely to be admitted to the hospital with COVID-19 than their unvaccinated peers. They were also 51% less likely to die of of the disease.