Photographer: Mark Kauzlarich / Bloomberg
Photographer: Mark Kauzlarich / Bloomberg
Coronavirus vaccines were just launched in December, when more than 1,000 employees Cedars-Sinai Medical Center in Los Angeles volunteered for a large study. Purpose: to identify how immune reactions to jab may vary.
Until last month, a clear pattern in the data “appeared in our country,” said research leader Susan Cheng. Those who recovered from Covid-19 responded to their first blow so strongly that the results rivaled never-infected colleagues who had received both blows. The implication was clear. If you have had Covid, you may only need one of the two recommended doses of Pfizer and Modern.
“We didn’t expect this to come out as a smoking weapon,” said Cheng, who co-authored writing Nature Medicine. In fact, if you’ve already had the virus, your immune response after a vaccine is probably better than that of a person who has never been infected after two, according to Italian research just published in the New England Journal of Medicine.
The issue of administering a single dose to people who had Covid became all the more urgent as safety issues arose regarding Johnson & Johnson and AstraZeneca vaccines. The implications at a time of tense global supply are striking: offering people previously infected with an mRNA vaccine alone could deliver more than 110 million doses worldwide, according to a calculation by University of Maryland, Mohammad Sajadi School of Immunology and colleagues.
“Remembering” Covid
Sajadi is co-author one of the recent studies that is part of a recent series of findings, all aimed in the same direction: the immune system in people who had Covid “remembers” the virus, so a first vaccine acts as a strong stimulant for existing defenses. “The data is very clear,” Sajadi said. “Each study showed that you get a very clear and strong memory response.”
Healthcare workers administer doses of Pfizer-BioNTech Covid-19 vaccine in an arena on the campus of San Diego State University in San Diego, California.
Photographer: Bing Guan / Bloomberg
Since February, several European countries – inclusive France, Spain, Italy and Germany – have adopted policies that offer Covid survivors a single dose of two-dose vaccines.
In Israel, the world leader in coronavirus vaccinations, health authorities initially withheld vaccines from recovered Covid patients, but in February recommended receiving a single shot. New research suggests that the booster vaccine adds protection against newer variants that have emerged in the UK, South Africa and Brazil.
“We believe our study supports the recommendation to administer a dose of vaccine to recovered individuals to protect against the original and SARS-CoV-2 variants of concern,” Michal Mandelboim, head of the Israeli National Center for Influenza and Respiratory Viruses, said in a statement. . e-mail. A The study in “Science” found that in Covid survivors, vaccinations massively increased immunity against variants.
In the US, the Centers for Disease Control and Prevention recommends two more doses of the vaccine for people who have had Covid, but growing evidence that a single vaccine may be enough is under discussion. The US has given enough doses to 31% of its population, while Israel has given enough to 57%, according to the Bloomberg Vaccine Follower.
Required data
In a blog post, the director of the National Institutes of Health, Francis Collins, argued that the administration of single-dose survivors could “contribute to expanding the vaccine supply and speeding up more vaccination.”
“But any serious analysis of this option will require more data,” he warned in February.
Since then, a study after another reinforced the idea of a single vaccine for survivors, though some skeptics have pointed out that it is logistically easier to give them both doses than to realize who only needs one.
In the US, the vaccine supply is relatively plentiful, Sajadi said. But “for other countries, especially places where it is difficult to get vaccinated, this is still an important question. And it’s also an important question in general, because you don’t want to give someone a medical intervention they don’t need. ”
If a patient who had Covid asked Sajadi at this time if they needed a second vaccine, he said, it would make sense to omit it if none of their medical history indicate problems with immune responses.
Cheng from Cedars-Sinai said he would continue to follow the CDC’s recommendations for two vaccines, even for people who had Covid. The data suggests, however, that one dose might be enough, she said – and this could be true for other types of people: “I think we’re just at the top of the iceberg to find out who they are. ”