Breakthrough Infections Cause ‘Super Immunity’ to COVID-19

Source: Freepik

According to a newly published study, breakthrough infections can generate super immunity to other COVID-19 variants.

As the coronavirus continues to mutate, researchers are warning of waning immunity following COVID-19 vaccinations. The increased risk of breakthrough infections has led multiple countries to approve booster doses. However, the effect of breakthrough infections on the body’s immune response remains unclear. Recently, researchers found evidence of delta variant breakthrough cases conferring people with ‘super immunity’.

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.

Dr. Fikadu Tafesse, senior author

Vaccinated vs Breakthrough

A team of researchers at Oregon Health & Science University recruited fully vaccinated health care workers diagnosed with a breakthrough infection between January 31, 2021, and August 18, 2021. Genomic sequencing helped confirm which variant caused the infection. Out of the 26 people that developed a breakthrough infection, 10 had delta variant, 9 had non-delta infections and the rest had an unknown variant. The study also recruited a control group consisting of fully vaccinated individuals with no history of breakthrough infection. All study participants had received two doses of the Pfizer vaccine.

Results revealed a greater number of antibodies in samples from breakthrough cases than samples collected two weeks after the second dose of Pfizer. Moreover, these antibodies were almost 1,000 times more effective.

Next, the researchers exposed blood samples of the two study groups to live coronavirus. Despite a mild infection, samples from breakthrough cases generated a more robust immune response than the vaccinated group. Additionally, these antibodies worked better at neutralizing the virus.

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.

Dr. Marcel Curlin, study author

Although the study did not assess immunity to the new Omicron variant, study authors expect omicron breakthrough infections to generate a similar immune response.


Timothy A. Bates et al, Antibody Response and Variant Cross-Neutralization After SARS-CoV-2 Breakthrough Infection, JAMA (2021). DOI: 10.1001/jama.2021.22898


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