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
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
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
, 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.