Over 7000 cases of hospital admission or death because of covid-19 could have been avoided during just one wave of the pandemic if everyone in the UK had received the full number of recommended SARS-CoV-2 vaccination doses, a study of the population has reported.1
To look at the problem of undervaccination during the pandemic, researchers from the Health Data Research UK (HDR UK) consortium conducted the country’s first whole population level analysis involving individual level health data.
Focusing on the summer of 2022 (June to September), they found that undervaccination across the four nations was associated with a higher risk of severe covid-19 outcomes, especially in people 75 and over and those aged 16 to 74.
During the study period the recommended doses were one dose for those aged 5 to 11, two doses for those aged 12 to 15, three for those aged 16 to 74, and four for those aged 75 and over.
The paper, published in the Lancet, reported that on 1 June 2022 44% of the population aged 5 or over had not had the recommended dose. This number varied across the four nations, however, with 50% of Northern Ireland, 46% of England, 34% of Scotland, and 33% of Wales being undervaccinated.
Over the four month study period, there were 40 393 severe covid-19 outcomes (hospital admission or death), with 14 156 of these occurring in undervaccinated participants.
The research team then carried out modelling to estimate how many severe outcomes could have been avoided if the population had been fully vaccinated on 1 June. They reported that 7180 severe outcomes could have been avoided, including 210 (95% confidence interval 94 to 326) in the 5 to 15 age group, 1544 (95% CI 399 to 1689) in the 16 to 74 age group, and 5426 (95% CI 5340 to 5512) in the 75 and older age group.
Speaking at the Science Media Centre briefing on the study, author Angela Wood, associate director of the BHF Data Science Centre at HDR UK, said that compared with full vaccination “children aged 5 to 15 were over two times more at risk, adults aged 16 to 74 were 50% more at risk, and adults aged 75 and over were over three times more at risk” of a severe outcome.
She added that “people were more likely to be undervaccinated if they were male, younger, from more deprived backgrounds, of non-white ethnicity, or had fewer underlying health conditions.”
“Landmark advance”
Co-author Cathie Sudlow, chief scientist and deputy director of HDR UK, said that the study was made possible by the acceleration in data infrastructure that took place during the pandemic.
“This study relied on secure access to anonymised health data for pretty much everyone across the four nations of the UK. That’s 67 million people. Therefore, the results are inclusive and relevant to everyone, regardless of their age, ethnic group, geography, or socioeconomic status. And that’s an important advance,” she said. “We now know that this sort of thing is possible. This type of approach could be, and should be, extended to many other areas of medicine which are as deserving of this approach.”
Sudlow added, however, that while the NHS’ “cradle to grave records” mean the UK is in a “unique position to realise the potential of these types of health data,” there are still problems for researchers when it comes to data access. “Access is often a lengthy and fragmented process, so the potential for improving healthcare through these types of studies is not yet being realised in full,” Sudlow said. “We think this landmark study sets a line in the sand to show this sort of thing is possible and we need to be doing more of it.”
