The first coronavirus vaccinations administered nationwide have raised hopes of a breakthrough in the fight against COVID-19, but experts are now raising an even more hopeful possibility: that people may only need one injection instead of the current two-dose regimen.
The prospect would effectively double the number of vaccine doses available and ensure that more people can be vaccinated quickly. But the idea has sparked a debate, with experts saying there isn’t enough evidence yet to justify a single dose and that people should plan on getting two doses.
The drive to explore the idea of a single-dose vaccine crystallized with a recent New York Times opinion of Michael Mina, an immunologist at Harvard TH Chan School of Public Health, and Zeynep Tufecki, a sociologist who has many written on the pandemic.
They called for a new clinical trial to be started immediately to investigate whether one dose of the vaccine is sufficient. They cited data from the studies already conducted for the Pfizer and Moderna vaccines that showed protection started after the first dose, with efficacy as high as about 90 percent, compared to about 95 percent 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 explored immediately.
“If that turns out to be the case, this would be a game changer, allowing us to vaccinate up to twice as many people and significantly alleviate suffering, not only in the United States, but also in countries where vaccine shortages can last for years. solve it, ‘they wrote.
Part of the question is how aggressive it is to go on with a single dose that may be slightly less effective than two doses, but that protection would spread to twice as many people at a time that an average of about 2,500 Americans are on it every day. virus. day and vaccines are not on track to be widely available for months.
“What can we do now so that we don’t kill 60,000 people in a month?” said Christopher Gill, a professor of global health at Boston University School of Public Health. He said there should at least be a debate about vaccinating twice as many people with a single dose immediately, without waiting for another trial.
“If you wait, you might be dead,” he said.
Scott Gottlieb, a former commissioner to the Food and Drug Administration (FDA), questioned the government’s strategy of withholding half the doses to make sure there is enough for everyone to get their second dose. considering that in the worst case a single dose dose is still at least partially as good.
The administration is withholding 2.9 million doses to serve as the second dose for the 2.9 million people vaccinated in the first week, instead of using all doses at once, said Deputy Secretary of Health and Human Services Brett Giroir.
“We know that the first dose is partially protective, that data is now available, so you want to try and get as many doses out as possible to give as many people as possible some benefit,” said Gottlieb, who is now on the Pfizer board. said on CNBC earlier this month.
Other experts, including those from Operation Warp Speed and the FDA, are pushing back those pointing to one dose, noting that months of careful research have been conducted on the two-dose regimen.
“The second dose will be an integral part of the label when the vaccines are approved,” Moncef Slaoui, Operation Warp Speed’s chief science adviser, said at a news conference. “It consolidates the patients’ immunity to COVID-19, which is the data that shows long-term immunity, at least for a few months. And I expect it to last a very long time. So people should not use the vaccine as a single vaccine. “
Still, he left the door open to continue studying. “You could ask the question, why not conduct efficacy trials with a single dose vaccine of the Moderna vaccine or the Pfizer vaccine?” he added. That would be a valid question. Timing would of course be a big challenge. “
Peter Marks, the FDA official overseeing the vaccine review, noted in a separate press conference that the studies and reviews are based on two doses.
“We have spent so much time carefully reviewing the data and basing our decisions on science that it seems rather reckless to assume that one dose might be okay without knowing it,” he said.
Mina, the Harvard professor, says the US should pursue a new lawsuit so they know for sure, which he said would take two to three months.
“Even if it is slightly inferior, it could be better from a public health standpoint,” he said on a single dose, meaning that a slightly less effective vaccine spread to twice as many people will accelerate the overall spread of the virus. would help reduce.
Moderna said it had no plans for a new trial.
“We have only studied a two-dose regimen and believe it is very effective in all age groups with an expectation of durability,” said a Moderna spokesperson. “We do not currently plan to study a single dose regimen.”
Meanwhile, Eric Topol, a professor of molecular medicine at Scripps Research, said it’s important to communicate to people that they need two doses until more is known.
“The points to study this are good, but the public message to many that they are skipping the second dose is troubling if we don’t really know what protection that will provide,” he tweeted.
There is also another vaccine in the pipeline, from Johnson & Johnson, which could yield results from the phase three trial early next year. The vaccine uses only a single dose.