Photographer: Mark Kauzlarich / Bloomberg
Photographer: Mark Kauzlarich / Bloomberg
Vaccines against the coronavirus were just rolled out in December when more than 1,000 employees joined The Cedars-Sinai Medical Center in Los Angeles volunteered for an extensive study. The goal: to determine how the immune responses to the shot can vary.
Last month, a clear pattern emerged in the data, said study leader Susan Cheng. Those who recovered from Covid-19 reacted so strongly to their first shot that the results rivaled uninfected colleagues who had received both injections. The implication was clear. If you’ve had Covid, you may only need one of the two recommended doses Pfizer and Modern.
“We didn’t expect this to stand out like a smoking gun,” said Cheng, who was a co-author the Nature Medicine article. In fact, if you already had the virus, your immune response after one vaccine is likely to be even better than that of a never-infected person after two, according to Italian research has just appeared in the New England Journal of Medicine.
The issue of giving just a single dose to people who have been on Covid has become all the more urgent since safety concerns have arisen over Johnson & Johnson’s and AstraZeneca’s vaccines. The implications at a time of tense global supply are striking: Giving previously infected people just one injection of mRNA vaccine could release more than 110 million doses worldwide, according to a calculation by Immunologist Mohammad Sajadi and colleagues from the University of Maryland School of Medicine.
“Reminder” of Covid
Sajadi was a co-author one of the recent studies that fits into a recent set of findings that all point in the same direction: the immune systems of people who have had Covid ‘remembers’ the virus, so an initial vaccine acts as a powerful booster of existing defenses. “The data is very clear,” said Sajadi. “Every study has shown that you get a very clear and strong memory response.”
Health professionals administer doses of the 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 – including France, Spain, Italy and Germany – have adopted policies whereby Covid survivors receive only one dose of the two-dose vaccines.
In Israel, a world leader in coronavirus vaccinations, health authorities initially did not withhold any vaccinations from recovered Covid patients, but in February advised them to get one shot. New research there suggests the booster vaccine offers protection against newer variants originating in the UK, South Africa and Brazil.
“We believe our study supports the recommendation to administer one dose of vaccine to recovered individuals to protect against the original and SARS-CoV-2 variants of concern,” said Michal Mandelboim, head of the Israeli National Center for Influenza and Respiratory Viruses. , in an email. A Research in “Science” found that vaccinations in survivors of Covid greatly increased immunity to variants.
In the US, the Centers for Disease Control and Prevention still recommend two vaccine doses for people who have had Covid, but the growing evidence that one vaccine could be enough is currently under discussion. According to the Bloomberg Vaccine, the US has given enough doses to 31% of the population, while Israel has given enough doses to 57%. Tracker.
Data required
In a blog post, Francis Collins, director of the National Institutes of Health, raised the possibility that giving a single dose to survivors could “help expand the vaccine offering and get more people vaccinated earlier.”
“But more data is needed for serious consideration of this option,” he warned in February.
From that moment on, a study after that another has bolstered the idea of a single vaccine for survivors, though some Skeptics have pointed out that it is logistically easier to give everyone two doses than to figure out who only needs one.
In the US, there are relatively many vaccines, Sajadi said. But “for other countries, especially places that are struggling to get vaccinations, this is really still an important question. And it’s also an important question in general, because you don’t want to just give someone a medical intervention that they don’t need. “
If a patient who had had Covid asked Sajadi at the time if they needed a second vaccine, he said, he would say it would make sense to skip it if nothing in their medical history indicated problems with immune responses.
Cedars-Sinai’s Cheng said she still would not meet CDC guidelines calling for two vaccines, even for people who have had Covid. However, the data suggests that one dose might be enough, she said – and so could other types of people: “I think we’re just at the tip of the iceberg to find out who they are.”