COVID vaccine efficacy wanes, but jabs offer protection: Study

Oxford University researchers say efficacy of Pfizer, AstraZeneca weakens 90 days after second dose, but both ‘still doing really well against Delta’ strain.

The efficacy of two widely used coronavirus vaccines against the Delta variant weakens within three months of inoculation, but the jabs remain the most effective way to ensure protection against the strain, Oxford University researchers have found. Two doses of the Pfizer and AstraZeneca vaccines provide protection levels of up to 75 and 61 percent respectively, 90 days after inoculation, they said in the largest study of its kind, published on Thursday. That is down from 85 and 68 percent, respectively, seen two weeks after the second jab is administered.