About 7000 people in the UK would not have died or been admitted to hospital due to covid-19 over the summer of 2022 if they had been fully vaccinated against the virus, a large study has found. This marks the first time the health consequences of covid-19 vaccine hesitancy have been calculated for an entire country.
Since the advent of the omicron variant, covid-19 vaccines are no longer very effective at stopping people from getting infected, but they still cut the risk of dying or needing to be admitted to hospital due to the virus.
Catherine Sudlow at the University of Edinburgh in the UK and her colleagues used health service data for the country to explore how much of an effect vaccination had on hospital cases and deaths in the summer of 2022, when most covid-19 restrictions had ended there.
Sudlow’s team included data from 1 June to 30 September 2022, spanning a covid-19 wave that peaked in July. During this period, 40,000 people either died or needed to be admitted to hospital due to the virus, both of which were classed as a severe health outcome.
The team then compared rates of severe outcomes in people who had received the recommended number of covid-19 vaccines and boosters – for instance, four doses in people aged 75 and older by that point – with those who had received fewer than the recommended doses or none at all.
People who hadn’t had all their doses were more likely to get severely ill than those who were fully vaccinated, with the exact increase in risk varying with age. For instance, those who were 75 or older were about three times more likely to have a severe covid-19 outcome if they hadn’t received all their vaccines.
The team calculated that if everyone in the UK had received all their doses, there would have been about 7000 fewer deaths and hospitalisations. “Being fully vaccinated leads to a reduction in harmful outcomes across society,” says Sudlow.
One caveat is the fact that the study wasn’t a randomised trial – the best kind of medical evidence – but merely observed correlations between vaccination status and outcomes, which can bias the results, says Stephen Evans at the London School of Hygiene and Tropical Medicine.
Nevertheless, the study’s findings about vaccine effectiveness are broadly consistent with previous randomised trials, he says. “Their approach is a reasonable one.”