Pfizer & AstraZeneca Covid-19 vaccines ‘highly effective’ in vulnerable people in UK, study of 1 million jab recipients finds

The Covid-19 vaccines made by Oxford-AstraZeneca and Pfizer-BioNTech are just as effective in people with underlying conditions as the rest of the population, a UK study of one million participants has shown.

Last year the British government advised clinically extremely vulnerable people to stay at home – known as “shielding” – to protect themselves from the virus, before dropping its recommendation last month

Conditions including diabetes, severe asthma, and diseases that weaken the immune system – like blood cancer – have all been linked to an increased risk of hospitalisation or death from Covid-19.

On Friday, the government said a Public Health England (PHE) study had shown that people with such conditions are protected against symptomatic infection by two doses of the Pfizer or AstraZeneca vaccines – the UK’s most widely used Covid jabs.

The report, published in preprint format without being peer-reviewed, showed an efficacy of 60% among at-risk groups for either vaccine after one dose.

After a second dose, this rises to 81% for AstraZeneca among the ‘at risk’ 16-64 age cohort, PHE said in a statement.

For people in at-risk groups aged 65 and over, the efficacy is 89% for Pfizer and 80% with AstraZeneca.

For people with weakened immune systems, the efficacy for either jab after a first dose is only 4%, although this rises substantially to 74% after a second dose.

“This real-world data shows for the first time that most people who are clinically vulnerable to Covid-19 still receive high levels of protection after two doses of vaccine,” Dr Mary Ramsay, Head of Immunisation at PHE, said.

The study’s authors addressed the relatively low protection of 4% that one dose of the vaccines offers immunosuppressed people.

The result “stands out,” they said, but they added that once people with weakened immune systems get a second dose they would only see a “minor reduction in vaccine effectiveness” compared to people who aren’t clinically vulnerable.

In the UK, more than 86% of people have received a first dose of a Covid-19 vaccine, while 65% have received a second dose, according to the latest data from Thursday.

The government reduced the interval between doses for clinically vulnerable people from 12 to 8 weeks in May, and it now says everyone in this group should have been offered a second dose.

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