The Los Angeles Times summarizes the results of a new medical study conducted by Northwestern University researchers on antibody levels protecting against Covid-19 in 974 people. “Those who were immunized against COVID-19 with two doses of an mRNA vaccine and received a booster shot about eight months later saw their levels of neutralizing antibodies skyrocket.
“Among this group of 33 fully vaccinated and boosted people, the median level of these antibodies was 23 times higher one week after the booster shot than it had been just before the tune-up dose.”
What’s more, their median post-booster antibody level was three times higher than was typical for another group of people whose antibodies were measured a few weeks after getting their second dose of vaccine, when they’re close to their peak.
And it was 53 times higher than that of a group of 76 unvaccinated people who had recovered from COVID-19 just two to six weeks earlier. Even compared to a group of 73 people who had weathered a bout with COVID-19 and went on to get two doses of an mRNA vaccine, the boosted group’s median antibody level was 68% higher.
Study leader Alexis Demonbreun, a cell biologist at Northwestern University’s Feinberg School of Medicine, said the data demonstrate that no matter how well protected a vaccinated person may think she is, getting a booster shot is likely to increase her neutralizing antibodies — and with it, her immunity — considerably. And because scientists expect large antibody responses to create more durable immunity, the protection afforded by the booster should last longer than the initial two-shot regimen did…
Among their other findings: After receiving two doses of vaccine, people who’d already had an asymptomatic infection were typically no better protected than vaccinated people who had never been infected.
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