June 29, 2022 | Erin Bluvas, bluvase@sc.edu
The National Institute of Allergy and Infectious Diseases has awarded nearly $400K to Xueying Yang, a research assistant professor in the Department of Health Promotion, Education, and Behavior (HPEB) and with the South Carolina SmartState Center for Healthcare Quality (CHQ). She will use the two-year R21 grant to study how well the COVID-19 vaccine works for individuals living with HIV.
“People living with HIV appear to be at an elevated risk of COVID-related illness, hospitalization and death,” says Yang, whose research focuses on HIV prevention, stigma/discrimination and health outcomes. “However, the efficacy of COVID-19 vaccines for this group remains unclear because people living with HIV were not representatively included in the initial randomized-controlled trials and did not account for a large proportion in the existing efforts to investigate vaccine efficacy among immunocompromised populations in the real world.”
According to Yang, the fast-paced development of effective SARS-CoV-2 vaccines is a remarkable scientific achievement that has the potential to dramatically alter the COVID-19 pandemic. Clinical trials demonstrated safety and efficacy in preventing symptomatic COVID-19 infection though a small percentage of fully vaccinated individuals developed breakthrough cases.
Once these vaccines were deployed, the Centers for Disease Control and Prevention was able to collect data on these breakthrough infections in real-world settings. They report that 27 percent of these breakthrough cases were asymptomatic, 10 percent of patients were hospitalized, and two percent died – with 87 percent of those deaths occurring in people 65 years of age or older. Yang will build on this knowledge with her new study.
“Understanding COVID-19 vaccine efficacy in real-world settings is critical to helping disease monitoring and preventing the resurgence of COVID-19 cases,” she says. “Early research suggests that, among vaccinated individuals, people living with HIV may mount a similar immune defense against infection compared to people without HIV, but contradictory results have also been observed – including a faster decline of antibody levels for people living with HIV.”
According to researchers, this discrepancy could be explained by T cell depletion, uncontrolled viral load and/or HIV disease severity. These possible deficiencies of COVID-19 vaccines raise global concerns for the estimated 40 million people living with HIV around the world.
Yang’s project will move researchers’ understanding of COVID-19 vaccine efficacy beyond small case reports to capture robust evidence from large, population-level cohorts in real-world settings. A partnership with the UofSC Big Data Health Science Center – where Yang is an R25 Fellow – will provide the large volume of electronic health record data required to assess the efficacy of the vaccines in real-world settings and at the population level.
Since 2017, Xiaoming Li, an HPEB professor who leads both CHQ and the Big Data Health Science Center, and his team have used NIH funding to examine treatment gaps among more than 12,000 people living with HIV in South Carolina. At the outset of the pandemic, the researchers established a South Carolina COVID-19 cohort – integrating patients’ electronic health records beginning with the year prior to the outbreak.
Leveraging this data, Yang will compare the prevalence and disease severity of breakthrough infections between people living with and without HIV, further analyzing the data by immunosuppression level, vaccine type and underlying medical conditions. She will also examine whether HIV markers (e.g., T cell counts, viral suppression, AIDS stage) and treatment (e.g., antiretroviral therapy) play a role in COVID-19 vaccine efficacy.
“This research is essential to promoting health equity and better informing clinical treatment,” Yang says. “Enhancing our understanding of breakthrough infections of vulnerable groups may help to develop guidance to improve their protection through preventive measures such as continued social distancing or by additional active or passive vaccinations.”