On Aug. 26, 2021, Oregon Health & Science University (OHSU) announced a laboratory study found that blood serum drawn from people previously vaccinated or naturally infected show ‘significantly reduced’ defense against two widely circulating variants of the novel coronavirus SARS-CoV-2.

Researchers said that their findings emphasize the importance of vaccinations combined with maintaining public health measures to cut off the spread of the SARS-CoV-2 virus.

Researchers found two variants of concern – B.1.1.7 originating in the U.K., and B.1.351 originating in South Africa – show reduced neutralization by antibodies in the blood of almost 100 people who were vaccinated with the Pfizer vaccine or previously infected by the virus. In the case of the B.1.351 variant, researchers measured a nine-fold reduction in effectiveness compared to the original SARS-CoV-2 virus.

Even so, researchers took it as a positive development that vaccination and earlier infections still mustered some residual protection against the two variants of concern. That finding appears to be consistent with a general reduction in the rate of hospitalizations and deaths worldwide, despite the increasing prevalence of the variants. The OHSU findings are generally consistent with other recent reports.

Co-senior author Marcel Curlin, M.D., associate professor of medicine (infectious diseases) in the OHSU School of Medicine, said the findings suggest that the Pfizer vaccine continues to provide some level of protection against variants even though the overall level of neutralizing antibodies is lower than against the earlier strain of SARS-CoV-2. He said the findings mean that it’s likely people will need vaccine boosters in the future, similar to an annual influenza shot.