Neutralizing antibody responses assessment after vaccination in people living with HIV using a surrogate neutralization assay

Objective: HIV has been reported to interfere with protective vaccination against multiple pathogens, usually through the decreased effectiveness of the antibody responses. We aimed to assess neutralizing antibody responses induced by COVID-19 vaccination in PLWH in Brazzaville, Republique of the Congo.

Method: The study was conducted at the Ambulatory Treatment Center of the National HIV Program, in charge of over 6000 PLWH, and the health center of FCRM in Brazzaville, Republic of the Congo. Participants were divided into two groups: PLWH with well-controlled HIV infection (CD4 counts no older than one week ≥ 800 / mm³, undetectable viral load of a period no older than one week and regularly taking Highly Active Antiretroviral Therapy for at least 6 months) and PLWOH. These groups were subdivided by vaccination status: fully vaccinated with adenovirus-based vaccines (Janssen/Ad26.COV2.S and Sputnik/Gam-COVID-Vac) or inactivated virus vaccine (Sinopharm/BBIP-CorV) and a control group of unvaccinated healthy individuals. All participants were RT-PCR negative at inclusion and/or with no documented history of SARS-CoV-2 infection. ELISA method was used for detecting IgG and neutralizing Antibodies against SARS-CoV-2 antigens using a commercial neutralizing assay.

Results: We collected oropharyngeal and blood samples from 1016 participants including 684 PLWH and 332 PLWOH. Both PLWH and PLWOH elicited high levels of antibody responses after complete vaccination with inactivated virus vaccine (Sinopharm/BBIP-CorV) and adenovirus-based vaccines (Janssen/Ad26.COV2.S and Sputnik/Gam-COVID-Vac). Overall, no difference was observed in neutralization capacity between PLWOH and PLWH with well-controlled HIV infection.

Conclusion: The results from this study underline the importance of implementing integrated health systems that provide PLWH the opportunity to benefit HIV prevention and care, at the same time while monitoring their vaccine-induced antibody kinetics for appropriate booster schedules.