With COVID-19 antibody testing becoming more accessible, does a positive result mean you are immune? Not necessarily.
Scientists at The Ohio State University College of Veterinary Medicine have developed a way to screen for specific antibodies that fight the SARS-CoV-2 virus, which could indicate whether someone is at a reduced risk for reinfection.
The new lab test looks specifically for "neutralizing" antibodies, distinguishing those that are potentially protective. As it turns out, not all antibodies work the same way.
"With many assays currently in use, we can detect antibodies, but that doesn't tell us if they're neutralizing antibodies. We only know the level of antibodies someone has," said Dr. Shan-Lu Liu, professor in the Ohio State College of Veterinary Medicine's Department of Veterinary Biosciences. "Some antibodies might be protective, some might not be protective, and some might even enhance infection – we know with this type of coronavirus and some other viruses, some antibodies can even do harm."
The research was published in JCI Insight this month.
Dr. Liu and his colleagues analyzed blood from people who tested positive for COVID-19. They found ICU patients had the most neutralizing - or potentially protective - antibodies. Meanwhile, convalescent plasma donors and health care workers had the lowest level of antibodies.
"So, the more severe the disease, the higher the antibody levels produced," Dr. Liu said. "What this tells us is there is a wide spectrum of different antibody levels after infection."
Why is this important? Antibodies can tell us more about the spread of the virus in our communities. While polymerase chain reaction (PCR) tests can tell you if you are positive in the moment, antibody tests show past infection - crucial information for public health strategies.
"If you know the antibody level, that will probably give you an idea about the overall infection rate," Dr. Liu said.
To read more about the findings, click here.