A SINGLE dose of a coronavirus vaccine may be all that is needed for people who have already been infected with covid-19.
A small study suggests that in people receiving the Pfizer/BioNTech vaccine, the body's response to natural infection with SARS-CoV-2 seems to act like a first dose of the vaccine.
Mark Mulligan at New York University and his colleagues tracked antibody levels in 32 people who were given both doses of the vaccine, and one person who had both doses of the Moderna jab. About half had previously contracted covid-19.
About two weeks after a first dose, people who had recovered from covid-19 had antibody levels similar to or higher than those of people who had never been infected but had received both doses. The results were announced on 9 March online at the Conference on Retroviruses and Opportunistic Infections.
A separate study of 109 people in New York who had received either the Pfizer/BioNTech or the Moderna vaccine revealed similar findings.
Alongside antibodies, other aspects of the immune response may still be improved by two doses, such as T-cell activity, says Stephen Evans at the London School of Hygiene & Tropical Medicine. “If you're offered two doses, I would take them even if I thought I had been infected, because it would probably boost my overall response and it might make me more likely to respond to a variant,” he says.
The US Centers For Disease Control and Prevention hasn't changed its guidance, which is that people with a confirmed, recent acute covid-19 infection may choose to temporarily delay vaccination, if desired.