Evaluation of COVID-19 antibodies, cell-mediated immunity and telomeres following COVID-19 immunization or natural infection in an immune compromised population: An HIV Cohort Study

Due to a critical need, vaccines against SARS-COV-2 were developed and introduced into practice in record time. This has led to a lingering uncertainty about vaccine efficacy and safety in immune compromised populations, such as persons with HIV (PWH), not specifically studied in the registration trials. There is also little data published in PWH on the immunologic response to COVID-19 infection or immunisation when stratified by age or CD4 count. As both may carry major clinical implications for poor immunity, an in-depth assessment of natural and vaccine-mediated immune response to COVID-19 in PWH is needed. We aim to assess the initial antibody response and its rate of decline and also levels of cell-mediated immunity (CMI) in PWH after COVID-19 infection or vaccination. Factors including age, sex, ethnicity, CD4 nadir, HIV viral suppression, antiretroviral therapy, co-morbidities, co-infections, vaccine type and COVID-19 variant strains will be correlated with loss of COVID-19 antibodies and markers of CMI. We will also study the association between telomere length and COVID-19 disease severity and vaccine-mediated immune response. We will use a well characterized longitudinal cohort of >2020 PWH accessing care at the Southern Alberta Clinic (SAC) and the comprehensive database that routinely collects data on the clinical and demographic factors listed above. We will identify PWH who have i) had COVID-19 infection or ii) received a COVID-19 vaccine or iii) declined immunization between 01/07/2021-01/07/2022. As routine care, bloodwork is obtained quarterly, and aliquots are stored in a biobank. Using both stored and prospective samples we will test for antibody response, markers of CMI and changes in telomere length associated with COVID-19 disease and vaccine. This will be linked to the database to stratify our analysis and evaluate confounding and effect modification. This work will assess severity of COVID-19 disease and efficacy of vaccination in PWH.