Vaccination Plus Breakthrough Infection Might Give ‘Super Immunity’ Against New Variants

FRIDAY, Dec. 17, 2021 (HealthDay News) -- Breakthrough infections in people who've been vaccinated against COVID-19 may trigger "super immunity" against coronavirus variants, including Omicron, according to a new study.

"The key is to get vaccinated. You’ve got to have a foundation of protection," said co-author Dr. Marcel Curlin, an associate professor of medicine at Oregon Health & Sciences University (OHSU) in Portland.

For the study, he and his colleagues collected blood samples from 52 people who were fully vaccinated with the Pfizer vaccine.

Twenty-six, the control group, did not have breakthrough infections, while the other 26 had mild cases of COVID after vaccination. That included 10 participants with the highly contagious Delta variant, nine with non-Delta variants and seven with unknown variants.

In lab tests, live coronavirus was exposed to blood from the study volunteers in order to assess immune response. Compared to the control group, blood from those with breakthrough infections generated more antibodies -- and, the study found, those antibodies were much better at neutralizing the live virus.

The antibodies in the blood of people with breakthrough infections were as much as 1,000% more effective than antibodies generated two weeks after the second dose of the Pfizer vaccine, researchers reported.

The study -- published online Dec. 16 in the Journal of the American Medical Association -- is the first of its kind, and researchers said it suggests that immune response triggered by a breakthrough infection is likely to be highly effective against current and future coronavirus variants.

“You can't get a better immune response than this," said senior author Fikadu Tafesse, assistant professor of molecular microbiology and immunology at OHSU.

He noted that these vaccines are "very effective" against severe disease. "Our study suggests that individuals who are vaccinated and then exposed to a breakthrough infection have super immunity,” Tafesse said in an OHSU news release.

Curlin, who is also medical director of OHSU Occupational Health, thinks it all speaks to an eventual end game.

"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," he explained.

"Our study implies that the long-term outcome is going to be a tapering-off of the severity of the worldwide epidemic," Curlin added in the release.

Researchers did not look at the new Omicron variant, which was first reported in late November.

Based on the study findings, Tafesse said they anticipate that breakthrough infections from Omicron will generate a similarly strong immune response among vaccinated people.

More information

The U.S. Centers for Disease Control and Prevention has more on breakthrough infections.

SOURCE: Oregon Health & Science University, news release, Dec. 16, 2021