In a new study from the University of Nottingham, researchers found that people who’ve already encountered SARS-CoV-2 may gain a big boost against COVID-19 if they get just one dose of the Pfizer vaccine.
More importantly, the protection may extend to new viral variants.
In the study, the team tested 45 health care workers, including 20 who had tested positive previously for SARS-CoV-2 and 25 who had not.
Their COVID-19 antibody status was tracked via blood samples beginning in April 2020, and when the Pfizer vaccine became available everyone received a first dose, followed by a second dose 10 weeks later.
The team found getting the second dose of the vaccine was especially important, boosting both the potency and breadth of neutralizing antibodies against SARS-CoV-2.
What’s more, this effect was magnified to an even higher level in people who’d already been infected with the new coronavirus.
The team also found that even though the Pfizer shots that previously infected people received were formulated to fight the original (2019) variant of the virus, blood samples from people who’d had an encounter with COVID-19 were shown to “neutralize” the later Beta form of the virus, as well.
That suggests that each new dose of vaccine given may help even the previously infected fight off emerging COVID-19 variants, although data on the new (and most infectious) Delta variant is lacking.
These findings provide evidence that continued immunogenic challenge [vaccine], even in previously infected patients, is beneficial.
It also suggests that this repeated immunogenic challenge may somehow spread to cover new variants.
Future work is needed to test the vaccine effect on the Delta variant.
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The study is published in Science Translational Medicine. One author of the study is Richard Urbanowicz.
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