British study shows Covid-19 vaccine efficacy wanes under Delta

The Oxford University study found that 90 days after a second shot of the Pfizer or AstraZeneca vaccine, their efficacy in preventing infections had slipped to 75 percent and 61 percent respectively.

A British public health study has found that protection from either of the two most commonly used Covid-19 vaccines against the now prevalent Delta variant of the coronavirus weakens within three months.