UAMS researchers say the results demonstrate the need for vaccinations.
A statewide COVID-19 antibody study led by the University of Arkansas for Medical Sciences found that by the end of 2020, 7.4 percent of Arkansans had antibodies to the virus, but there were wide disparities among racial and ethnic groups. UAMS researchers released their findings this week to a public database, medRxiv.
The study included analysis of more than 7,500 blood samples from children and adults across the state. It was conducted in three waves from July to December 2020. The work was supported by $3.3 million in federal coronavirus aid that was then allocated by the Arkansas Coronavirus Aid, Relief and Economic Security (CARES) Act Steering Committee created by Governor Asa Hutchinson.
Unlike diagnostic tests, COVID-19 antibody testing looks back into the immune system’s history, according to a press release. A positive antibody test means the person was exposed to the virus and developed antibodies against SARS-CoV-2, the virus that causes the disease known as COVID-19.
“An important finding of the study is the significant differences in COVID-19 antibody rates detected within specific racial and ethnic groups,” said Dr. Laura James, the study’s principal investigator and director of the UAMS Translational Research Institute. “Hispanic populations were almost 19 times more likely to have SARS-CoV-2 antibodies than whites, and Blacks were five times more likely to have antibodies as whites during the course of the study.”
These findings highlight the need to understand factors that impact infection in underrepresented minority populations, she added.
The UAMS team collected blood samples from children and adults. The first wave (July/August 2020) revealed low rates for antibodies, averaging 2.6 percent in adults. However, by November/December, 7.4 percent of adult samples were positive.
Blood samples were collected from individuals seen at medical clinics for non-COVID reasons and who were not known to have had COVID-19 infection. The antibody positivity rates reflected cases of COVID-19 in the general population.
While the overall positivity rate in late December was relatively low, the findings are important because they indicate previously unrecognized COVID-19 infections, said UAMS’ Dr. Josh Kennedy, a pediatric allergist and immunologist who helped lead the study.
“Our findings underscore the need for everyone to get vaccinated as soon as they can,” Kennedy said. “Very few people in the state have immunity from a natural infection, so vaccination is key for getting Arkansas out of the pandemic.”
The team found little difference in antibody rates between rural and urban residents, which surprised researchers who thought rural residents might be less exposed.
The antibody test was developed by UAMS’ Karl Boehme, Craig Forrest and Dr. Kennedy. Boehme and Forrest are associate professors in the College of Medicine Department of Microbiology and Immunology.
The UAMS Fay W. Boozman College of Public Health helped identify study participants through their contact tracing call center. In addition, samples were obtained from UAMS Regional Program sites across Arkansas, the Arkansas Federation for Medical Care and the Arkansas Department of Health.
Faculty within the College of Public Health and College of Medicine participated in the epidemiologic and statistical evaluation of the data and included College of Public Health Dean Mark Williams, Benjamin Amick and Wendy Nembhard, as well as Ruofei Du and Jing Jin.