Healthcare

If You Had COVID, One Dose Of The Pfizer Vaccine May Be Enough, Studies Suggest

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A single dose of Pfizer’s coronavirus vaccine may offer sufficient protection against the virus for people who have already had COVID-19, two studies published Thursday show.

“This could potentially accelerate vaccine rollout,” researchers at University College of London and Public Health England said in the first study. “With increasing variants, wider coverage without compromising vaccine-induced immunity could help reduce variant emergence.”

In the first study, researchers examined 51 London health workers who had been routinely tested for antibodies and the coronavirus since March. Among nearly half of those who had the virus, just one dose of the Pfizer-BioNTech vaccine increased their antibody count “more than 140-fold from peak pre-vaccine levels,” the study said.

In the second study, researchers at Imperial College London examined antibodies in 72 health workers in December. Among the approximately one-third of whom had shown signs of previous infection, one shot had “very strong” antibody and T-cell responses.

The two studies are just the latest indications that one shot of Pfizer’s vaccine — instead of the two doses initially recommended — may offer enough protection against COVID-19. A separate study published in The Lancet last week examining Israeli health care workers found that Pfizer’s vaccine was 85% effective in preventing symptomatic COVID-19 cases after just one dose.

Both Pfizer and Moderna’s vaccines were engineered as two-dose inoculations given four and three weeks apart, respectively, but states across the country have reported supply shortages that have slowed their administration. Johnson & Johnson’s applied for emergency authorization from the Food and Drug Administration for its one-dose coronavirus vaccine, and could be approved as soon as Saturday.