Some SARS-CoV-2 Antibodies Are More Protective Than Others in Preventing COVID-19 Reinfection, Finds Study

Researchers have found that some antibodies to SARS-CoV-2, the virus that causes COVID-19, are more protective than others, when it comes to reinfection.

This information, discovered from the joint study by researchers at the University of Tennessee Health Science Center (Memphis, TN, USA) and their colleagues at MD Anderson Cancer Center (Houston, TX, USA), has implications for the overall understanding of the virus and whether infection actually does trigger immunity. The researchers used an assay or test procedure developed in their lab roughly 25 years ago to study the infection mechanism of Ebolavirus. They applied that assay to study infection of and immunity generated against SARS-CoV-2. The researchers used the assay to test for the presence of neutralizing antibodies in samples from 134 hospitalized COVID patients and 464 healthy individuals obtained between June 2017 and June 2020.

“Companies have developed assays to show whether people have SARS-CoV-2 antibodies, but these assays only provide a yes or no answer. So why is our work important? We can determine the amount of neutralizing antibody present in the blood, and neutralizing antibodies are the ones that can prevent the individual from becoming infected. If you have an antibody to an internal component of the virus, then that means you have been infected, but those antibodies won’t prevent infection,” said Michael Whitt, PhD, one of the principal investigators on the antibody study, which is ongoing at UTHSC.

“Neutralizing antibodies are directed to the spike (S) protein, which is responsible for the binding of the virus to receptors on a host cell and for entry of the virus into the cell,” Dr. Whitt explained. “However, not all antibodies to the S protein have neutralizing activity, so it is only a subset of antibodies to the S protein that can prevent infection. One of the questions we wanted to address is, do all people who have had the disease, COVID-19, generate neutralizing antibodies? That answer is clearly, no. The other question is, for those who do produce neutralizing antibodies, how much do they make?”

“What we don’t know is how much neutralizing antibody is needed to prevent infection or reinfection,” Dr. Whitt added. “Just because you have detectable antibodies doesn’t mean that you’re protected from infection.”

Related Links:
University of Tennessee Health Science Center
MD Anderson Cancer Center