Vaccination, Previous Infection Offer Reduced Protection Against Certain COVID-19 Variants of Concern

Blood serum drawn from individuals who have previously been vaccinated against or naturally infected with COVID-19 have significantly reduced defense against 2 widely circulating variants of SARS-CoV-2, according to a study published in Nature Communications. Investigators from Oregon Health and Science University (OHSU) said that it is crucial to emphasize the importance of vaccinations, as well as the maintenance of public health measures that cut off the spread of the virus.

“We know that the virus continues to evolve for its own advantage,” said co-senior author Fikadu Tafesse, PhD, assistant professor of molecular microbiology and immunology in the OHSU School of Medicine, in a press release.

The investigators found that 2 variants of concern—the Alpha variant and the Beta variant—show reduced neutralization by antibodies in the blood of nearly 100 people who were either vaccinated with the Pfizer vaccine or previously infected by SARS-CoV-2. In terms of vaccine response to the Beta variant in particular, they found a 9-fold reduction in efficacy compared to the original virus. However, it was interpreted as a positive development that vaccination and earlier infection offered some protection against these 2 variants.

According to the study, the reduction in antibodies was particularly noticeable in adults over 50 years of age.

“The people who surround our older and more vulnerable populations need to get vaccinated and minimize exposure to the virus,” said Bill Messer, MD, PhD, assistant professor of molecular microbiology and immunology and medicine (infectious diseases) in the OHSU School of Medicine, in the release. “You can’t just walk into a nursing home because they’re all vaccinated. If you’re not vaccinated, that’s still a problem.”

To conduct the study, the researchers cultivated a cell line of the original SARS-CoV-2 virus as well as the 2 variants of concern. Samples of each virus type were then mixed with blood samples collected from 50 people in Oregon who previously received the Pfizer vaccine along with 44 who had been previously infected with the coronavirus.

According to Marcel Curlin, MD, associate professor of medicine (infectious diseases) in the OHSU School of Medicine, the findings suggest that the vaccine provides some level of protection against SARS-CoV-2 variants, despite the overall level of neutralizing antibodies being lower. He expressed confidence that widespread vaccinations, in combination with effective public health measures such as social distancing and masking, will reduce the momentum of the pandemic.

“Influenza has a much larger potential for variability than the coronavirus,” Curlin said in the release. “Hopefully, coronaviruses will be easier to manage.”

The investigators said their study also suggested that booster shots, similar to annual influenza shots, are likely to be necessary in the future.

“We have learned to cope with influenza,” Messer said in the release. “I think we will learn to do the same with COVID-19 as well.”

REFERENCE

Study confirms virus variants reduce protection against COVID-19 [news release]. EurekAlert; August 26, 2021. Accessed August 30, 2021. https://www.eurekalert.org/news-releases/926609