These patients generate antibodies that were as much as 1,000% more effective than compared to those generated two weeks after the second Pfizer COVID-19 vaccine, according to a Journal of the American Medical Association article published this week.
"We have not examined the omicron variant specifically, but based on the results of this study we would anticipate that breakthrough infections from the omicron variant will generate a similarly strong immune response among vaccinated people," senior author Dr. Fikadu Tafesse noted in a press release.
Researchers collected blood samples from participants who were fully vaccinated with the Pfizer COVID-19 vaccine, then compared a 26-person control group without any breakthrough infections with 26 participants who were diagnosed with mild cases of COVID-19 after being vaccinated.
Of those with breakthrough infections, 10 participants had the delta variant, nine had non-delta variants, and seven had unknown variants, but because the study was done between January and August of this year, the omicron variant was not included.
After the researchers exposed the study volunteers’ blood samples to live coronavirus, participants who had breakthrough infections not only generated more antibodies compared to the control group, but were also 1,000% more effective at neutralizing the virus than antibodies generated two weeks after the second dose of the Pfizer vaccine.
"You can’t get a better immune response than this," Tafesse said.
"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."
They added, however, that the limitations of the study were a small sample size and the time difference between the control group and those participants with breakthrough infections from initial vaccination to their blood samples collection, which preliminary data suggests may contribute to cross-neutralizing antibody responses due to circulating variants.
"I think this speaks to an eventual end game," said co-author Dr. Marcel Curlin.
"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."
"Our study implies that the long-term outcome is going to be a tapering-off of the severity of the worldwide epidemic."