UK details more real-world data showing COVID-19 vaccine cuts serious illness in elderly

The UK government said Monday that Public Health England (PHE) has submitted a pre-print of real-world data showing that a single dose of either Pfizer or AstraZeneca's respective COVID-19 vaccines cut hospital admissions among people ≥80 years in the UK by about 80%. "This adds to growing evidence showing that the vaccines are working to reduce infections and save lives," commented Mary Ramsay, PHE's head of immunisation, adding "while there remains much more data to follow, this is encouraging and we are increasingly confident that vaccines are making a real difference."

PHE submitted its analysis for peer-review after providing initial findings of the vaccines' real-world impact in older adults last week. The study evaluated the effect of vaccination with Pfizer and partner BioNTech's BNT162b2, as well as AstraZeneca and the University of Oxford's AZD1222, in over 7.5 million people aged ≥70 years in England. Specifically, it looked at the impact on PCR-confirmed symptomatic infection rates and hospitalisations, and in the case of Pfizer's product, for which there was more data because it was the first to be authorised, deaths from COVID-19 as well.

Since January, protection against symptomatic COVID-19 from about four weeks after the first injection, ranged between 57% and 61% for one dose of BNT162b2, and between 60% and 73% for AZD1222. The data also indicate that symptomatic infections in over 70s decreased from around three weeks after one dose of both vaccines. Meanwhile, among those ≥80 years, researchers said that "vaccine effects were noted from 10 to 13 days after vaccination," reaching an effectiveness rate of 70% at about the four-week mark, before plateauing, and then climbing to 89% starting at 14 days after dose two.

BNT162b2 cut deaths by 85% after single dose

Aside from protection against symptomatic disease, people given one dose of BNT162b2 had an additional 43% lower risk of emergency hospitalisation and an additional 51% lower risk of death. There was not enough follow-up data to assess the effect of AstraZeneca's vaccine on mortality due to the later rollout, but researchers said a single dose of AZD1222 was associated with an additional 37% lower risk of emergency hospitalisation. "Combined with the effect against symptomatic disease, this indicates that a single dose of either vaccine is approximately 80% effective at preventing hospitalisation and a single dose of BNT162b2 is 85% effective at preventing death with COVID-19," the study authors said.

A separate study in healthcare workers, dubbed SIREN, has shown that one dose of a vaccine can reduce the risk of symptomatic and asymptomatic infection by 72%. Despite the positive data after first doses, Jonathan Van-Tam, England's deputy chief medical officer, said it is "absolutely critical" that second doses "are still part of the course of immunisation against COVID-19 and no less important." There was a "significant likelihood" that a second dose would "mature your immune response, possibly make it broader and almost certainly make it longer than it would otherwise be in relation to a first dose only," the UK official noted. Still, he suggested the new findings offer a glimpse of how the vaccine programme "is going to hopefully take us into a very different world in the next few months."

Decision on AstraZeneca's vaccine 'vindicated'

Van-Tam also said the latest data have "vindicated" the UK's decision to administer AstraZeneca's vaccine to the elderly, while some other countries, including Germany, had opted to restrict AZD1222 to those under 65 years citing a lack of clinical evidence in older age groups. However, Van-Tam said the UK's Joint Committee on Vaccination and Immunisation had taken the view that it was "not immunologically plausible" the vaccine would work in younger age groups, but not older ones.

Meanwhile, Germany may soon change its stance on AstraZeneca's product for seniors. Thomas Mertens, head of the country's Standing Committee on Vaccination, said it is "possible" the vaccine could also be cleared in older people after all. "We never criticised the vaccine, we just criticised the lack of data for the over-65 age group," said Mertens, although he admitted that the distinction may have been lost to much of the public, leading to doses of AZD1222 piling up in storage due to public scepticism. Mertens said "the whole thing has somehow gone wrong."

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