Study finds Pfizer, AstraZeneca COVID-19 vaccines effective against Indian variant of coronavirus

Sunday, May 23, 2021

A study by Public Health England (PHE), conducted between April 5 and May 16, found today the Pfizer- and AstraZeneca- made COVID-19 vaccines are effective against the B.1.617.2 variant of the coronavirus, first identified in India, offering a similar level of defence as against Lineage B.1.1.7, first identified in Kent, England.

Two doses of the Pfizer vaccine was, two weeks later, 88% effective in stopping symptomatic disease arising from the India variant and 93% against the Kent variant. Two doses of the AstraZeneca jab was 60% effective against the India variant and 66% against the Kent variant. However, after one dose of either, both vaccines were 33% effective against the India variant, compared to 50% against the Kent variant. PHE expects even higher rates of efficacy relating to hospital admissions and deaths, and both Sky News and The Guardian have indicated there is data suggesting it takes a longer time for the AstraZeneca jab to reach peak effectiveness.

The study’s analysis included 12,675 genomic-sequenced cases from all age groups and of several ethnicities: 11,621 of the Kent variant and 1,054 of the India variant. Head of immunisation at PHE Dr Mary Ramsay said the findings “[provide] reassurance that two doses of either vaccine offer high levels of protection against symptomatic disease from the B.1.617.2 variant”. The study said the “[n]umbers of cases and follow-up periods are currently insufficient to estimate effectiveness against severe disease, including hospitalisation and mortality”. It has nonetheless concluded that, while there was “an absolute reduction of one dose vaccine effectiveness against symptomatic disease with the B.1.617.2 variant of approximately 20% when compared to the B.1.1.7 variant”, “reductions in vaccine effectiveness after two doses were very small.”

PHE has said the difference in efficacy figures between the second dose of vaccines could be due to the slower rollout of the AstraZeneca jab, which was approved for use in the UK nearly a month after the Pfizer one.

The study, which is not peer-reviewed, comes ahead of UK Prime Minister Boris Johnson’s plan to ease COVID-19 lockdown restrictions in England by June 21. Johnson indicated May 14 the India variant “could pose a serious disruption to our progress”. Strategic COVID-19 response director at PHE Dr Susan Hopkins said “[w]e have now got early evidence that the vaccine protects” against the India variant, but that it was “too early to say” whether the reopening plans would be disrupted. She also said the trend indicated by the data was “quite clear”, and in the “right direction”.

The study’s lead author and consultant medical epidemiologist at PHE Dr Jamie Lopez Bernal says there is more confidence in data relating to the first dose than that from the second because “[t]here are bigger numbers that have been vaccinated with one dose.” He concluded “we classify that as moderate certainty around the first dose, but low levels of confidence around the second dose.”

Health Secretary of the United Kingdom Matt Hancock was encouraged by the findings, saying, according to a government press release, “[w]e can now be confident that over 20 million people – more than one in three – have significant protection against this new variant” against the India variant, and calling the study’s findings “groundbreaking”. He went on to encourage everyone, according to The Guardian, to get the jab.

Official government data says over 37 million Britons have received their first dose of a COVID-19 vaccine, and over 22 million their second, crossing a milestone of over 50 million doses. Another study from the PHE has said immunisations have prevented, from up to May 9, 13 thousand deaths and 39,100 hospital admissions among older people in England.

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