Photographer: Mark Kauzlarich / Bloomberg
Photographer: Mark Kauzlarich / Bloomberg
Coronavirus vaccines had just been rolled out in December, when more than 1,000 employees Cedars-Sinai Medical Center in Los Angeles volunteered for a large study. The goal: to pinpoint how immune reactions to the spike can vary.
Last month, a clear pattern of data “appeared to us,” research leader Susan Cheng said. Those who had recovered from the Covid-19 responded to their first shot so strongly that the results rivaled never-infected colleagues who had received both shots. The implication was clear. If you have had Covid, you may only need one of the two doses recommended for Pfizer i Modern.
“We didn’t expect this to jump like a smoking gun,” said Cheng, who co-authored the writing of Nature Medicine. In fact, if you already have the virus, your immune response after a vaccine is likely to be even 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 giving only a single dose to people who have had Covid has become more urgent, as safety issues have been raised about Johnson & Johnson and AstraZeneca vaccines. The implications at a time of tense global supply are staggering: giving previously infected people just one mRNA vaccine could release more than 110 million doses worldwide, according to a calculation for Immunologist Mohammad Sajadi and colleagues at the University of Maryland School of Medicine.
“Remembering” Covid
Sajadi is a co-author one of the recent studies that adapts to a recent wave of findings pointing in the same direction: the immune system in people who have had Covid “remembers” the virus, so a first vaccine acts as a powerful booster for existing defenses. “The data is very clear,” Sajadi said. “All studies have shown that you get a very clear and strong memory response.”
Health workers administer doses of the Pfizer-BioNTech Covid-19 vaccine on a campus of the San Diego State University campus in San Diego, California.
Photographer: Bing Guan / Bloomberg
Since February, several European countries included France, Spain, Italy and Germany have adopted policies that give Covid survivors only one dose of two-dose vaccines.
In Israel, the world leader in coronavirus vaccinations, health authorities initially fully withheld vaccines from patients recovered from Covid, but in February recommended that they receive a single vaccine. There is new research suggesting that the booster vaccine adds protection against newer variants that originated 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 them against the original and SARS-CoV-2 variants of concern,” said Michal Mandelboim, head of the Israel National Center for to Influenza and Respiratory Viruses. e-mail. A a study in “Science” found that in Covid survivors, vaccines massively increased immunity to variants.
In the United States, Centers for Disease Control and Prevention recommends two doses of vaccine for people who have had Covid, but increasing evidence is being discussed that one vaccine might be enough. The U.S. has given enough doses to 31 percent of its population, while Israel has given enough to 57 percent, according to the Bloomberg vaccine. Tracker.
Necessary data
In a blog post, the director of the National Institutes of Health, Francis Collins, raised the possibility that giving survivors a single dose could “help expand the supply of vaccines and vaccinate more people sooner.”
“But any serious consideration of this option will require more data,” he warned in February.
Since then, a study later another has reinforced the idea of a single vaccine for survivors, though some skeptics have pointed out that it is logistically easier to give just one dose to everyone than to find out who only needs one.
In the U.S., the supply of vaccines is relatively plentiful, Sajadi said. But “for other countries, especially places that have difficulty getting vaccinated, this is still an important issue. And it’s also an important question, in general, because you don’t want to have a medical intervention that doesn’t need someone ”.
If a patient who had had Covid at the time asked Sajadi if they needed a second vaccine, he said he would say it would make sense to skip it if nothing in his medical history indicated problems with immune responses.
Cheng, in Cedars-Sinai, said he would continue to violate CDC guidelines for requesting two vaccines, even for people who have had Covid. The data suggests, however, that one dose might be enough, he said – and that could also be true for other types of people: “I think we’re just at the tip of the iceberg to find out who they are.”