The first coronavirus vaccines administered nationwide have raised hopes of a breakthrough in the fight against COVID-19, but experts now raise an even more promising possibility: that people may only need one shot instead. of the current two-dose regimen.
The possibility of effectively doubling the number of available doses of vaccine and would allow more people to be vaccinated quickly. But the idea has sparked a debate, and experts say there is still not enough evidence to justify a single dose and that people should plan two.
The push to explore the idea of a single-dose vaccine crystallized with a recent New York Times publication by Michael Mina, an immunologist at the Harvard TH Chan School of Public Health, and Zeynep Tufecki, a sociologist who has written much about the pandemic.
They called for a new clinical trial to be started immediately to study whether a dose of the vaccine is sufficient. They cited data from trials already conducted for Pfizer and Moderna vaccines that showed protection started after the first dose, with up to 90% efficacy, compared to 95% efficacy after two doses.
There are questions about how long protection will last without the second booster dose, but Mina and Tufecki wrote that the possibility of needing just one dose should be studied immediately.
“If it proves to be the case, that would change the game, which will allow us to vaccinate up to twice the number of people and greatly alleviate suffering not only in the United States, but also in countries where vaccine shortages can take years to solve, “they wrote.
Part of the question is how aggressive it is to go ahead with a single dose that may be a little less effective than two doses, but that would extend protection to twice as many people at once, when an average of about 2,500 Americans die from it. viruses every day and vaccines are not on the way to being widely available for months.
“What can we do now because in one month we haven’t had 60,000 people dead?” Said Christopher Gill, professor of global health at Boston University School of Public Health. He said that at least twice as many people should be vaccinated with a single dose immediately, without waiting for a new trial.
“If you wait, you might be dead,” he said.
Scott Gottlieb, former Food and Drug Administration (FDA) commissioner, questioned the administration’s strategy of withholding half the doses to make sure there is enough for everyone to get their second dose. , since, in the worst case, a single dose is still at least partially as good.
The administration withholds 2.9 million doses to serve as a second dose for the 2.9 million people vaccinated in the first week instead of deploying all doses at once. dit Undersecretary of Health and Human Services Brett Giroir.
“We know the first dose is partially protective, that the data is available now, so you want to try to get as many doses as possible to give as many people as possible some benefit,” said Gottlieb, who is now in the Pfizer’s board of directors told CNBC earlier this month.
Other experts, including those from Operation Warp Speed and the FDA, are backing down on those who point to a dose, noting that months of careful study of the two-dose regimen were conducted.
“The second dose is a complete part of the label if vaccines are approved,” Moncef Slaoui, chief scientific adviser to Operation Warp Speed, told a news conference. “It strengthens the immunity of patients against COVID-19, and this is the data that shows a long-lasting immunity, at least for a few months. And I hope it is very durable. Therefore, people should not take the vaccine as a single dose vaccine.
Still, he left the door open to continue studying. “The question might be asked, why not do efficacy trials with a single-dose vaccine from the Modern vaccine or the Pfizer vaccine?” added. “It simply came to our notice then. Of course, the timing would be a big challenge. “
Peter Marks, an FDA official overseeing the vaccine review, noted at an independent press conference that the trials and reviews have been based on two doses.
“We spent so much time carefully reviewing the data and basing our decisions on science, that it seems pretty absurd to guess that a dose might be right, without knowing it,” he said.
Mina, the Harvard professor, says the United States should hold a new trial so she can know for sure, which she said would take two or three months.
“Even if it’s slightly lower, from a public health perspective it can be higher,” he said of a dose, meaning a slightly less effective vaccine distributed in twice as many people would help reduce the overall spread. of the virus faster.
However, Moderna said she does not plan a new trial.
“We have only studied a two-dose regimen and believe it is highly effective in all age groups with an expectation of durability,” a Moderna spokesman said. “We currently have no plans to study a one-dose regimen.”
Meanwhile, Eric Topol, a professor of molecular medicine at Scripps Research, said it’s important to communicate to people who need to get doses until they find out more.
“The points for studying it are good, but the public message for many of skipping the 2nd dose is worrisome when we don’t really know the protection it provides,” he tweeted.
There is also another vaccine underway, from Johnson & Johnson, that could have results from its phase three trial early next year. The vaccine uses only a single dose.