How effective are the Covid vaccines?

Reports have filtered through this morning about Public Health England’s assessment of the efficacy of the two vaccines so far administered to the public. The results have not yet been published, but the efficacy rates quoted in the Sun suggest that the Pfizer vaccine has proved to be between 79 and 84 per cent effective at stopping symptomatic infection after two doses. After one dose – which is all that most people have had so far – efficacy is reported as 65 per cent. Among the over 80s it is very similar, at 64 per cent. No figures are given for the AstraZeneca vaccine but it is suggested that the efficacy is ‘similar’.

While the figures are encouraging, they do, nonetheless, indicate that the Pfizer vaccine could have a somewhat lower efficacy than the initial trial results suggested. An analysis of the data published by the US Food and Drug Administration in December showed that the Pfizer jab appeared to have an efficacy of 95 per cent after two doses. There