SARS-CoV-2 Antibodies Cross-React with Other Coronavirus Strains, Raising Important Implications for COVID-19 Diagnosis

A new study demonstrates that antibodies generated by the novel coronavirus react to other strains of coronavirus and vice versa, although antibodies generated by the SARS outbreak of 2003 had only limited effectiveness in neutralizing the SARS-CoV-2 virus.

The findings of the study by scientists from Oregon Health & Science University (Portland, OR, USA) could have important implications for vaccines and diagnosis of COVID-19. Given the speed of mutations – estimated at one to two per month – it’s not surprising that an antibody generated from a virus 18 years ago provides a meager defense against the new coronavirus. The researchers used individual antibody clones to test cross-reactivity, and that a body’s normal immune system will generate many antibodies that are more likely to neutralize a wider series of targets on the mutating virus.

The study also suggests that efforts to accurately discern a previous COVID-19 infection, by analyzing antibodies in blood, may be confounded by the presence of antibodies reacting to other strains of coronavirus including the common cold. Although this complicates diagnosis of older infections, researchers say the finding actually expands scientists’ ability to study the biology and disease-causing effects of the SARS-CoV-2 virus since they know it reacts to antibodies of multiple strains of coronaviruses.

“Our finding has some important implications concerning immunity toward different strains of coronavirus infections, especially as these viruses continue to mutate,” said senior author Fikadu Tafesse, Ph.D., assistant professor of molecular microbiology and immunology in the OHSU School of Medicine. “I don’t think there is any one size-fits-all vaccine. Although the vaccines coming out now may break the momentum of the virus and end the pandemic, they may not be the end game.”

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