People who contract a breakthrough infection after receiving the COVID-19 vaccine may acquire a "super immunity" to the virus, researchers from the Oregon Health & Science University found.
A study, which was published in the Journal of the American Medical Association, revealed antibodies in blood samples of those with breakthrough infections were as much as 1,000% times more effective than those generated two weeks following the second dose of the Pfizer vaccine.
As part of the study, blood samples were collected from 52 people, all university employees who received the Pfizer vaccine. A total of 26 people were identified as having mild breakthrough infections following vaccination. Of those cases, 10 involved the highly-contagious delta variant, nine were non-delta and seven were unknown variants, according to the study.
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"You can’t get a better immune response than this,” said Dr. Fikadu Tafesse, senior author and assistant professor of molecular microbiology and immunology at OHSU. “These vaccines are very effective against severe disease..."
Researchers say each exposure following vaccination strengthens immune response to subsequent exposures, even to new variants.
“I think this speaks to an eventual end game,” said co-author Dr. Marcel Curlin, associate professor of medicine in the OHSU School of Medicine. “It doesn’t mean we’re at the end of the pandemic, but it points to where we’re likely to land: Once you’re vaccinated and then exposed to the virus, you’re probably going to be reasonably well-protected from future variants."
The group also measured the immune response to live virus exposed to blood sampled from people with breakthrough cases and compared it with the immune response to the control group, the university said. They found the breakthrough cases generated more antibodies at baseline. Consequently, those antibodies were "substantially better" at neutralizing the live virus.
Researchers noted they haven't specifically examined the omicron variant, but based on the results of the study, it's anticipated that breakthrough infections from the variant will generate a similarly strong immune response among those who've been vaccinated.
“The key is to get vaccinated,” Curlin said. “You’ve got to have a foundation of protection.”