Is it better to give more protection to more people from COVID-19, or to give more protection to fewer people?
As a limited supply of vaccines begins to be distributed in parts of the world, some experts suggest that authorities go against the proposed vaccination schedule. Instead of taking two views on the rotation three or four weeks apart, they say it would be better to delay the second view and instead focus on the first view. volume for so many people.
With a pandemic out of control, they say, some protection is better than nothing.
And new data suggest that vaccines work well after one shot.
Many experts are not fond of the idea, however. There are still big questions about how long a defense lasts after the first sight and whether one design is sufficient to protect against emerging changes.
Experts agree that everyone needs a second look to get the highest and longest protection. The question is how soon after the first. The longer the second view can wait, the more people will get the first one.
Promising first impression
Some new data suggest that the first dose of the vaccine provides adequate protection.
The British government released figures showing that the Pfizer-BioNTech vaccine was 72% effective against infection after a single dose. It reduced the risk of hospitalization and death by 75%. In those over 80, the bullet cut the risk of death by more than half.
The report comes after an Israeli study published last Thursday showed similar results for the Pfizer-BioNTech vaccine.
It is welcome news for the British government, which decided to postpone the second sight for up to 12 weeks when a new, contagious variable put up COVID-19 cases late last year.
“[P]the first dose of vaccine will protect as many people as possible on the priority list protect the highest number of people at risk overall in the shortest possible time, “Britain ‘s chief medical officers said in statement announcing policy December 30th.
This approach “will have the greatest impact on reducing mortality, actual disease and hospitalization, and in protecting the NHS (National Health Service) and equal health services,” they said.
The British Immunological Society backed the government’s decision, saying a longer wait between shots of the latter would not be as effective.
“Most immunologists would agree that a delay in a second ‘boost’ dose of protein antigen vaccine … before eight weeks would be unlikely to have side effects,” the group said in a statement. .
Sustainability
One major concern, however, is how long protection from a single dose lasts.
“While the numbers [from] one dose looks interesting, the only thing is that we don’t know how stable it is, “U.S. infectious disease expert Anthony Fauci said in a statement Friday.
Because the virus is so new and the vaccines are even newer, scientists have little evidence to proceed.
But some researchers say they know enough, based on what they have learned from other vaccines.
“As soon as you get good protection, it will not suddenly disappear. It will gradually fade over time,” said Danuta Skowronski, director of epidemiology for influenza and respiratory diseases at the British Center for Disease Control. Colombia. “You have time to make those decisions about the second dose.”
“The thing is you don’t have time to waffling on the first dose of the vaccine while so many people are dying,” she said.
The second view not only generates a longer immune response, however. It also reinforces the strength of the response.
That could be especially important with new changes circulating.
Conventional vaccines are less effective against these variables. But they still seem to be preventing the worst COVID-19 cases, hospitalization and death.
“You want a lot of response … even if you reduce it, you don’t reduce it so much to get out of the defensive zone,” Fauci said.
But scientists do not know the extent of that.
It is also possible that people with less complete immunity may help to breed more drastic changes that weaken the vaccines.
However, some note, the virus moves the more it spreads, and even partial protection slows that spread.
The changes that have already emerged arose “before there was any vaccination at all,” noted Harvard University epidemiologist William Hanage.
Biologists who study viral evolution are “relatively calm” about the risk of under-vaccination breeding breeds, Hanage said. “I don’t think there’s any particular reason to think that delay is going to bring about more vaccine escape changes.”