[ad_1]
AstraZeneca’s COVID-19 vaccine shows it could reduce virus transmission and offers strong protection for three months with a single dose, researchers said on Wednesday in an encouraging turn in the epidemic’s suppression campaign.
Preliminary results from the University of Oxford, co-developer of the vaccine, could justify the British government’s controversial strategy of delaying the second vaccine for up to 12 weeks so more people can get a first dose quickly. So far, the recommended time between doses has been four weeks.
The research could also bring scientists closer to an answer to one of the big questions about the vaccination campaign: Will vaccines really curb the spread of the coronavirus?
It is not known what implications, if any, the results could have for the other two main vaccines used in the West, Pfizer and Moderna.
In the United States, Dr Anthony Fauci, the country’s leading infectious disease specialist, has rejected the idea of deliberately delaying second injections, saying the United States “will follow the science” and the data from clinical trials. The two doses of Pifzer and Moderna vaccines are supposed to be given three and four weeks apart.
Still, the research appears to be good news in the desperate effort to stop the spread of the virus, and also suggests a way to reduce vaccine shortages and get vaccines in more weapons faster.
The makers of all three vaccines have said their vaccines have been shown to be 70% to 95% effective in clinical trials in protecting people against illnesses caused by the virus. But it was not known whether vaccines could also suppress transmission of the virus – that is, whether a vaccinated person could still acquire the virus without getting sick and passing it on to others.
As a result, experts say even vaccinated people should continue to wear masks and keep their distance from others.
British study volunteers underwent regular nasal swabs to check for coronavirus, a proxy to try to answer the transmission question. The level of virus-positive swabs – combining volunteers who had an asymptomatic infection with those who showed symptoms – was 67% lower in the vaccinated group, the researchers reported.
While not a direct measure, “it must have a really beneficial effect on transmission,” Oxford principal researcher Sarah Gilbert said at a meeting of the New York Academy of Sciences on Wednesday.
The researchers also looked at the likelihood that people who were vaccinated would get an infection without symptoms. In a subset of volunteers, there were 16 asymptomatic infections among the vaccinated and 31 in an unvaccinated control group.
Pfizer and Moderna are also studying the effect of their vaccines on asymptomatic infections.
Only Pfizer and Moderna vaccines are used in the United States. Great Britain uses both AstraZeneca and Pfizer. AstraZeneca has also been licensed by the 27 countries of the European Union. Pfizer did not approve the UK government’s decision to lengthen the time between doses.
Mene Pangalos, executive vice president of biopharmaceutical research and development at AstraZeneca, said no patient had severe COVID-19 or had to be hospitalized three weeks after receiving a first dose, and that efficacy appeared to increase for up to 12 weeks after the initial shot.
“Our data suggests that you want to be as close to 12 weeks as possible” for the second dose, Pangalos said.
UK Health Secretary Matt Hancock said the study “supports the strategy we have adopted” to ensure that more people received at least one vaccine. The British move has been criticized as risky by other European countries.
Stephen Evans of the London School of Hygiene and Tropical Medicine said the study’s suggestion that a single dose protected people for 12 weeks was “helpful but not final.”
He said the authors themselves acknowledged that their research was not designed to study the vaccine dosing regimen and that their conclusions were based on statistical modeling and not on actual patients followed over time.
“It is certainly not very strong evidence, but there is also no indication that it is not the right thing to do,” Evans said of UK strategy.
One of the Oxford researchers, Dr Andrew Pollard, said scientists also believe the AstraZeneca vaccine will continue to provide protection against newer variants of COVID-19, although they are still awaiting data on this. . The rapidly spreading mutant versions have raised alarm around the world.
“If we need to update the vaccines, it’s actually a relatively straightforward process. It only takes a few months, rather than the tremendous efforts everyone put into the last year to get the trials on a massive scale, ”Pollard told the BBC.
Meanwhile, a UN-backed program to provide COVID-19 vaccines to those most in need around the world is brewing after a rocky start. The COVAX Facility on Wednesday announced plans for an initial distribution of around 100 million doses by the end of March and more than 200 million more by the end of June in dozens of countries.
Almost all of the doses expected for the first phase are expected to come from AstraZeneca and its partner, the Serum Institute of India. Deployment will depend on the World Health Organization’s authorization of the AstraZeneca vaccine for emergency use, which is expected to take place this month.
Some 190 countries and territories participate in COVAX, which has seen rich countries source vaccines, sometimes at high prices.
The worldwide death toll from the pandemic has eclipsed 2.2 million, including about 447,000 in the United States, according to data from Johns Hopkins University.
New cases per day in the United States and the number of Americans hospitalized with COVID-19 have fallen sharply in recent weeks, but deaths continue to stand at near all-time levels, at an average of d ‘about 3100 per day. Deaths are often behind the infection curve, as it can take weeks to get sick and die from COVID-19.
As Super Bowl looms, Fauci warns people against inviting others to Super Bowl parties, urging viewers to ‘keep it low and cool it off’ to avoid turning Sunday’s big game into a super spreader event.
“You don’t want parties with people you haven’t had a lot of contact with,” he told NBC’s “Today” show. “You just don’t know if they’re infected.”
Associated Press journalists Jill Lawless, Maria Cheng, Jamey Keaten, and Ricardo Alonso-Zaldivar and contributed to this report.
Receive Boston.com email alerts:
Sign up and receive the latest coronavirus news and updates, from our newsroom to your inbox.
[ad_2]
Source link