Gunilla Karlsson Hedestam is a Professor at Karolinska Institutet and partner of EPIVINF.
1. What motivated your research group to study COVID-19 vaccine responses specifically in people living with HIV?
The speed by which the Covid-19 vaccines were developed was unprecedented. Within one year of the SARS-CoV-2 outbreak, the first vaccines were approved and soon after deployed in many parts of the world. Scientists around the globe set out to understand vaccine responses in different population groups, including individuals with underlying health conditions who may not be expected to respond as well to vaccination as healthy people, such as people living with HIV (PLWH).
2. At a high level, what have you found so far? Do PLWH respond differently to COVID-19 vaccines compared to those without HIV?
The PLWH we studied were on anti-retroviral treatment. Thus, their level of viremia was controlled and their immune cell compartment intact.
Looking at overall antibody responses, PLWH produced similar levels of antibodies against the SARS-CoV-2 spike protein after COVID vaccination as healthy individuals. Other groups have reported similar results when studying treated patients, however, not everyone is on treatment, and without control of viremia the situation is different. We are currently studying the quality of the antibody response to see whether PLWH produce neutralizing antibodies that are as broad as those in individuals without HIV.
3. When tracking B cell lineages; the developmental pathways from stem cells to mature B cells and their descendants; over time, how does antibody evolution after infection and vaccination differ between HIV-positive and HIV-negative individuals?
Deep B Cell Receptor repertoire analysis and isolation of monoclonal antibodies require large numbers of cells, which are difficult to obtain from PLWH. Although we hope to collect such samples in the EPIVINF project, this is not guaranteed, so we are focusing mainly on serological analysis.
If large numbers of cells were available, we would study whether antigen-specific B cell lineages expand and undergo affinity maturation to the same extent as in healthy individuals. Because functional CD4+ T cells are needed for antibody affinity maturation, this process may be impaired in PLWH. However, it may also remain normal, depending on how well antiviral treatment suppresses the virus.
4. How could your findings influence future vaccine strategies for people living with HIV?
The question we aim to address focuses on qualitative aspects of the B cell repertoire and its evolution over time. If B cell responses to vaccination were found to be impaired in PLWH, closer immune monitoring would be recommended to help personalize and improve the vaccine regimen.
