Two AstraZeneca Covid-19 shots 85%-90% effective: UK real-world analysis

A double dose of COVID-19 vaccines is almost as effective against the fast-spreading variant of the coronavirus first identified in India as it is against Britain's dominant strain, English health officials said on Saturday.

LONDON (REUTERS) - Two doses of the Oxford-AstraZeneca Covid-19 vaccine is around 85 per cent to 90 per cent effective against symptomatic disease, Public Health England (PHE) said on Thursday (May 20), citing an analysis of real-world data from the roll-out of the shot.

Britain has suffered one of the worst death tolls globally from the pandemic, but has also had one of the fastest roll-outs of Covid-19 vaccines, generating a lot of data about the use of the shots in real-world settings.

In a weekly surveillance report, Public Health England said that the estimated effectiveness of the AstraZeneca vaccine, invented at the University of Oxford, was 89 per cent, compared with unvaccinated people.

That compares to 90 per cent estimated effectiveness against symptomatic disease for the Pfizer-BioNTech vaccine.

"This new data highlights the incredible impact that both doses of the vaccine can have, with a second dose of the Oxford/AstraZeneca vaccine providing up to 90 per cent protection," vaccines minister Nadhim Zahawi said.

PHE said the analysis was the first of its kind on the effectiveness of two doses of AstraZeneca in a real-world setting but was not yet published in a journal, adding more data would boost its confidence in the finding. 

Britain has been rolling out the shots manufactured by Pfizer and AstraZeneca since December and January respectively, and in April also started rolling out Moderna’s vaccine. 

PHE said there was a "small reduction in vaccine effectiveness" from 10 weeks after the first dose of the Pfizer shot before the second shot is given.

Britain extended the gap between doses to 12 weeks, though Pfizer warned there was a lack of evidence of its efficacy outside the three-week gap used in trials.

Last week, Britain cut the gap between doses down to eight weeks for people over 50, aiming to give maximum protection to more vulnerable people in the light of concern about the B16172 variant first reported in India.

Britain has been rolling out the shots manufactured by Pfizer and AstraZeneca since December and January respectively, and in April also started rolling out Moderna's vaccine.

PHE also estimated that the Covid-19 vaccine programme overall had prevented the deaths of 13,000 over-60s up to May 9, and stopped 39,100 of those over 65 from needing hospital treatment for Covid-19.