AstraZeneca’s COVID-19 vaccine does more than prevent people from becoming seriously ill – it appears to reduce transmission of the virus and offers strong protection for three months with just one dose, the researchers said on Wednesday in an encouraging campaign twist. to suppress the outbreak.
Preliminary results from the University of Oxford, a co-developer of the vaccine, may justify the British government’s controversial strategy of delaying the second injection for up to 12 weeks so that more people can receive the first dose quickly. So far, the recommended time between doses has been four weeks.
Research can also bring scientists closer to an answer to one of the big questions about the vaccination campaign: will vaccines really contain the spread of the coronavirus?
It is unclear what implications, if any, the findings may have for the two other major vaccines used in the West, Pfizer and Moderna.
In the United States, Dr. Anthony Fauci, the country’s leading infectious disease specialist, rejected the idea of deliberately delaying the second injection, saying the United States will “follow science” and clinical trial data. The two doses of the Pifzer and Moderna vaccines should be administered three and four weeks apart.
Still, the research appears to be good news in a desperate effort to stem the spread of the virus and also suggests a way to lessen vaccine shortages and inject more weapons into more weapons.
The manufacturers of the three vaccines said their vaccines have proven to be between 70% and 95% effective in clinical trials to protect people from illnesses caused by the virus. But it was unclear whether vaccines could also suppress the transmission of the virus – that is, whether an inoculated person could still acquire the virus without becoming ill and pass it on to others.
As a result, experts say that even vaccinated people should continue to wear masks and keep their distance from others.
The Oxford study, however, found that the vaccine not only prevents serious illnesses, but appears to cut transmission of the virus by two-thirds. The study has not yet been peer-reviewed.
Study volunteers underwent regular nasal smears. The level of positive smears for viruses – both those who had symptoms of COVID-19 and those who did not – was 67% lower in the vaccinated group.
“It must have a really beneficial effect on transmission,” said Oxford principal researcher Sarah Gilbert at a meeting at the New York Academy of Sciences.
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 those vaccinated and 31 in an unvaccinated comparison group.
Pfizer and Moderna are also studying the effect of their vaccines on asymptomatic infections.
Only the Pfizer and Moderna vaccines are being used in the United States. Britain is using those from AstraZeneca and Pfizer. AstraZeneca’s have also been authorized by the 27 nations of the European Union. Pfizer did not endorse the British government’s decision to lengthen the time between doses.
Mene Pangalos, executive vice president of research and development of biopharmaceuticals at AstraZeneca, said that no patient had severe COVID-19 or needed hospitalization three weeks after receiving the first dose, and that the effectiveness appeared to increase up to 12 weeks after the initial injection. .
“Our data suggest that you want to be as close to 12 weeks as possible” for the second dose, said Pangalos.
British Health Secretary Matt Hancock said the study “supports the strategy we have adopted” to ensure that more people receive at least one injection. Britain’s decision was 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 “useful, but not definitive.”
He said the authors themselves recognized that their research was not designed to investigate the vaccine’s dosing schedule and that their conclusions were based on statistical models, not on actual patients monitored over time.
“It is certainly not very strong evidence, but there is also no indication that this is the wrong thing to do,” said Evans of Britain’s strategy.
One of the Oxford researchers, Dr. Andrew Pollard, said that scientists also believe that the AstraZeneca vaccine will continue to offer protection against new variants of COVID-19, although they are still waiting for data on that. Rapidly spreading mutant versions have caused alarm worldwide.
“If we need to update the vaccines, then it is a relatively simple process. It only takes a matter of months, instead of the huge efforts that everyone made last year to get the large-scale tests to run, ”Pollard told the BBC.
In the meantime, a UN-backed program to provide COVID-19 vaccines to the most needy people around the world is preparing after a troubled start. The COVAX Facility announced plans on Wednesday for an initial distribution of around 100 million doses by the end of March and more than 200 million by the end of June to dozens of countries.
Almost all doses expected for the first phase must come from AstraZeneca and its partner, the Serum Institute of India. The implementation will depend on the authorization of the World Health Organization for the injection of AstraZeneca for emergency use, which is expected to happen this month.
About 190 countries and territories are participating in COVAX, which has seen rich countries buy supplies of vaccines, sometimes at premium prices.
The death toll from the pandemic worldwide has exceeded 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 dropped dramatically in recent weeks, but deaths are still close to the all-time high, at an average of about 3,100 per day. Deaths usually fall behind the infection curve, because it can take weeks to get sick and die from COVID-19.
As the Super Bowl approaches, Fauci is warning people against inviting others to the Super Bowl parties, urging viewers to “just be quiet and cool down” to avoid turning Sunday’s big game into a super publicity event.
“You don’t want to party with people you haven’t had much contact with,” he told NBC’s “Today” program. “You just don’t know if they are infected.”
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Associated Press reporters Jill Lawless, Maria Cheng, Jamey Keaten and Ricardo Alonso-Zaldivar contributed to this report.
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