Oxford Says Covid-19 Vaccine 76 percent Effective After One Dose for 3 Months

The COVID-19 vaccine developed by Oxford University and AstraZeneca has 76% efficacy against symptomatic infection for three months after a single dose, with efficacy improving when a second shot is given later, a preprint study showed on Tuesday.

Oxford University said the findings supported a decision made by Britain to extend the interval between initial doses and booster doses of the shot to 12 weeks.