AstraZeneca’s COVID-19 vaccine does more than prevent people from becoming seriously ill – it appears to reduce transmission of the virus and provides strong protection for three months with just a single dose, researchers said Wednesday in an encouraging turn in the campaign to increase outbreak. .
The preliminary findings of the University of Oxford, a co-developer of the vaccine, could justify the UK government’s controversial strategy of delaying the second shot for up to 12 weeks so that more people can get a first dose quickly. Until now, 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 vaccination urge: Will the vaccines actually slow the spread of the coronavirus?
It is not clear what implications, if any, the findings might have for the two other major vaccines used in the West, Pfizer’s and Moderna.
In the United States, Dr. Anthony Fauci, the country’s leading infectious disease expert, the idea of deliberately delaying second shots, saying the US is “following the science” and the data from the clinical trials. The two doses of the Pifzer and Moderna vaccines should be given three and four weeks apart.
Still, the research appears to be good news in the desperate effort to halt the spread of the virus, as well as suggesting a way to reduce vaccine shortages and get fired up more quickly.
The makers of all three vaccines have said their injections were found to be anywhere from 70% to 95% effective in clinical trials to protect people from illnesses caused by the virus. But it was unclear whether the vaccines could also suppress the transmission of the virus – that is, whether someone inoculated could still get the virus without getting sick and spread it to others.
As a result, experts have said that even people who have been vaccinated should continue to wear masks and keep their distance from others.
However, the Oxford study found that the vaccine not only prevented serious illness, but appeared to reduce the transmission of the virus by two-thirds. The study has not yet been peer-reviewed.
Volunteers in the study regularly had nasal swabs. The number of virus positive smears – of both those who had COVID-19 symptoms and those who had no symptoms – was 67% lower in the vaccinated group.
“That must have a very beneficial effect on the transfer,” said lead researcher Sarah Gilbert of Oxford at a meeting of the New York Academy of Sciences.
The researchers also looked at how likely people who have been vaccinated are to develop a symptom-free infection. In a subgroup 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 the Pfizer and Moderna vaccines are used in the United States. Great Britain uses both AstraZenecas and Pfizers. AstraZeneca’s is also approved by the 27-country European Union. Pfizer has not endorsed the UK government’s decision to extend the time between doses.
Mene Pangalos, executive vice president of biopharmaceuticals research and development at AstraZeneca, said no patient has experienced severe COVID-19 or required hospitalization three weeks after receiving a first dose, and its effectiveness appeared to be increasing up to 12 weeks after the first injection.
“Our data suggests 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 followed” to ensure that more people get at least one chance. Britain’s decision has been criticized by other European countries as risky.
Stephen Evans of the London School of Hygiene and Tropical Medicine said the study’s suggestion that a single dose protected humans for 12 weeks was “helpful but not definitive”.
He said the authors themselves acknowledged that their study was not intended to investigate the vaccine dosing schedule and that their conclusions were based on statistical models, not actual patients being followed over time.
“It is certainly not very strong evidence, but there is also no indication that this is the wrong thing to do,” Evans said of Britain’s strategy.
One of the Oxford researchers, Dr. Andrew Pollard, said scientists also believe the AstraZeneca vaccine will continue to protect against new variants of COVID-19, although they are still waiting for that. Spreading mutant versions have caused alarm around the world.
“If we have to update the vaccines, it is actually a relatively simple process. It only takes a matter of months, rather than the enormous effort everyone put into last year to get the very large-scale trials running, ”Pollard told the BBC.
Meanwhile, a UN-backed program to deliver COVID-19 vaccines to the neediest people worldwide is gearing up after a rocky start. The COVAX facility on Wednesday announced plans for initial distribution of approximately 100 million doses by the end of March and more than 200 million more by the end of June to dozens of countries.
Almost all doses expected for the first phase will come from AstraZeneca and its partner, the Serum Institute of India. The rollout is contingent upon the World Health Organization’s approval for the AstraZeneca emergency recording, which is expected to happen this month.
About 190 countries and territories participate in COVAX, which has led rich countries to amass stocks of vaccines, sometimes at inflated prices.
The global death toll from the pandemic has exceeded 2.2 million, including about 447,000 in the US, according to data from Johns Hopkins University.
The number of new cases per day in the US and the number of Americans hospitalized with COVID-19 have plummeted in recent weeks, but the number of deaths is still hitting nearly all record highs with an average of about 3,100 per day. Deaths often lag 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 not to invite others to Super Bowl parties, urging viewers to “just lay low and cool it down” to avoid Sunday’s big game in a superspreader event changes.
“You don’t want to party with people you haven’t interacted with much,” he told NBC’s “Today” show. “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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