Ad5-nCoV vaccine safe and effective against symptomatic, severe COVID-19, trials shows

One dose of Ad5-nCoV (Convidecia), a COVID-19 vaccine developed in China, is 57.5% effective against symptomatic COVID-19 and 91.7% effective against severe COVID-19 disease beginning 28 days postvaccination, according to a phase 3 randomized controlled trial published in The Lancet.