ABSTRACT
Background: People living with HIV (PWH) may represent a high-risk group for adverse clinical outcomes from SARS-CoV-2. The duration of protection from SARS-CoV-2 and emerging variants of concern (VOC) infection in PWH following vaccination is unclear. Furthermore, the role of preexisting SARS-CoV-2 immune responses, likely acquired from prior exposure to circulating human coronaviruses (HCoVs), on vaccine-mediated immunity remains to be determined. Understanding the kinetics of immune responses to SARS-CoV-2 and VOCs, and the impact of preexisting SARS-CoV-2 immunity on vaccine-mediated immune responses will be critical in informing COVID-19 vaccination policies in PWH. Methods: In this sub-study of the Phase II/III COV002 trial (open-label, non-randomised clinical trial ID: NCT04400838), 54 HIV+ male participants on antiretroviral therapy (undetectable viral loads, CD4+ T cells >350 cells/ul) and 50 HIV-sex and age-matched controls received two doses of ChAdOx1 nCoV-19 (AZD1222) 4-6 weeks apart and were followed for 6 months. Immune responses to vaccination were determined by ELISA (standard and MSD assay), neutralisation, ACE-2 inhibition, IFNγ ELISpot, activation-induced marker (AIM) assay and T cell proliferation assays. Results: 6 months after vaccination, antibody IgG levels to SARS-CoV-2 S and RBD proteins, ACE-2 inhibition and T cell responses to S protein were significantly higher than baseline (Table 1). Both humoral and cell-mediated immunity waned over time, but with no significant difference compared with HIV-individuals vaccinated with the same regimen. T and B cell-mediated immune responses to VOCs α, β, γ, and δ were detectable, although at lower magnitudes than wild type. Prior exposure to circulating β coronavirus HKU1 and OC43 was associated with measurable proliferative SARS-CoV-2 T cell response at baseline and a higher magnitude of post-vaccine T cell responses. Conclusion: Our data demonstrate no significant difference in ChAdOx1 nCoV-19 vaccine-mediated immune responses by HIV status. For all groups, we show waning but detectable immune responses against SARS-CoV-2 and VOCs 6 months after vaccination supporting the on-going policy to vaccinate against SARS-CoV-2 and reinforces the argument for long-term monitoring of responses.