By Jason Douglas and Jenny Strasburg 

LONDON -- New evidence from the U.K. showed Covid-19 vaccinations sharply reduced serious illness and deaths among elderly people after just one dose, bolstering optimism that successful vaccination programs offer a return to economic growth this year after a year of widespread lockdowns.

The real-world data from the country that is vaccinating a greater proportion of its population than any major Western economy also offers support for the U.K. government's strategy of stretching out limited vaccine supplies by delaying a second shot of vaccine by up to 12 weeks after the first to protect more people from the disease.

British researchers said in preliminary findings published online Monday that a single dose of Covid-19 vaccine developed either by Pfizer Inc. and BioNTech SE or the University of Oxford and AstraZeneca PLC reduced the risk of hospitalization among people over 70 years old by 80%, compared with those of a similar age who weren't vaccinated.

The study adds to evidence from across the world that vaccines are broadly as effective in the real world as they were shown to be in clinical trials, giving hope that mass rollouts can reduce the need for restrictive public-health measures and pave the way for economic reopening.

"It is going to hopefully take us into a very different world in the next few months," England's deputy chief medical officer Jonathan Van-Tam said Monday, referring to vaccination.

The study, which hasn't yet been reviewed by other scientists, should help dispel concerns in parts of Europe that AstraZeneca's shot doesn't have enough data to back up its rollout to at-risk over-65s.

It adds to broader evidence that the vaccines are saving lives. The U.K. program gave priority to the most vulnerable people, starting with the people over 80 and healthcare workers, before moving down the age scale.

On Jan. 19, U.K. government figures showed that 61% of all Covid-19-related deaths were of people over 80. On Feb 23, just 49% were from that age group. More than 20 million people in the U.K. have received at least one vaccine shot, around 38% of the adult population.

In the U.S., a vaccination push in nursing homes has also shown encouraging signs as government reports of new resident deaths from Covid-19 have been declining for weeks.

After recording more than 6,000 new resident deaths during a week in mid-December, U.S. nursing homes most recently reported 1,464 new resident deaths for the week ended Feb. 24, federal data show. That number will likely be revised higher in the next report, but not enough to change the declining trend.

The portion of weekly U.S. Covid-19 deaths from nursing homes has tumbled to the lowest levels since the federal government first tracked nursing-home statistics in late May last year, according to a Wall Street Journal analysis of the data. The declines in nursing home deaths are also outpacing declines in overall U.S. Covid-19 fatalities, data show.

The British study, led by England's public health agency, looked at health records associated with 7.5 million people over 70 in England, making it one of the largest such studies published to date. Researchers zeroed in on more than 150,000 people with test results matching vaccination records.

The scientists found a single dose of either vaccine reduced the risk of symptomatic Covid-19 and hospitalization from as little as 10 days after injection, with the strongest effects seen after 28 days. Results suggest both the Pfizer and AstraZeneca shots reduce the odds of symptomatic disease by around 60% in those over 70, after adjusting for factors including age, sex, ethnicity and location. The risk of hospitalization was around 80% lower for those getting a vaccine compared with those who didn't.

The study also examined the risk of hospitalization in the more-vulnerable over-80s who did develop symptoms, and the risk of death in the same group among those who received the Pfizer shot. Those vaccinated with symptoms had a 43% lower risk of admission to hospital compared with symptomatic unvaccinated cases, and their risk of dying of Covid-19 was halved.

Data on mortality for those who got the AstraZeneca shot weren't available because it was approved and rolled out later. Symptomatic cases among those vaccinated had a 37% lower risk of hospitalization than unvaccinated cases.

Public-health officials are especially upbeat on data showing the vaccines' effectiveness at reducing hospitalizations and deaths, even among older citizens most at risk. Researchers have also been optimistic about evidence that vaccines reduce transmission of the virus, and have said data so far suggest a single dose can help curb transmission even when the infected person doesn't have symptoms.

That optimism is tempered, however, by the emergence of new coronavirus variants that appear to make vaccines less effective. Genome sequencers in the U.K. have identified six cases of a variant that appears to have emerged in Brazil, prompting an effort to track down others who could have contracted the variant.

Globally, progress on vaccinations is patchy with countries such as the U.K. moving rapidly and others, including elsewhere in Europe, lagging behind.

Take-up of the Oxford-AstraZeneca shot in particular in parts of Europe has been slow, reflecting concern among some national regulators that the data on its effectiveness in over-65s were lacking. French President Emmanuel Macron added to the popular doubts, saying the vaccine was "quasi-ineffective for people older than 65 years."

British officials said that the latest data should put those fears to rest.

"I hope that right round the world people study these data," said Health Secretary Matt Hancock at a news conference Monday.

The U.K took the unusual step of extending the interval between first and second doses of vaccine to around 12 weeks from the month or so the manufacturers recommend. Scientific advisers said such a strategy would allow public-health officials to provide at least some protection to many more people in the early stages of the vaccine rollout.

Anthony Harnden, the deputy chair of the U.K.'s vaccine-advisory committee, said the data show that the U.K.'s strategy of stretching out doses to curtail deaths quickly was the right move and "has undoubtedly saved a large number of lives."

Researchers have also said it is still important that people receive their second dose. Some scientists have been worried that people could get careless, especially as they look forward to the lifting of tight lockdown restrictions.

--Max Colchester and Jon Kamp contributed to this article.

Write to Jason Douglas at jason.douglas@wsj.com and Jenny Strasburg at jenny.strasburg@wsj.com

 

(END) Dow Jones Newswires

March 01, 2021 16:34 ET (21:34 GMT)

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