HIV ‐1 viral load and reservoir size remain stable following SARS ‐ CoV ‐2 mRNA vaccination in people with HIV

Abstract Background The potent immunogenicity of mRNA vaccination raised concerns about its impact on HIV‐1 viral load (VL) and reservoir size in people with HIV, which could drive vaccine hesitancy. As part of a prospective clinical trial, we investigated whether SARS‐CoV‐2 mRNA vaccination induced changes in VL and reservoir size after a 1‐year three‐dose regimen in people with HIV on antiretroviral therapy (ART). Methods We collected blood samples from 37 people with HIV with varying degrees of immune reconstitution before vaccination and after receiving their second and third doses of vaccine. Anti‐SARS‐CoV‐2‐Spike antibodies and Spike‐specific CD4 + T‐cells were analysed as indicators of vaccine‐induced immunogenicity. The Intact Proviral DNA Assay was used to quantify the intact and defective HIV‐1 reservoir. Results Vaccination with three doses of SARS‐CoV‐2 mRNA vaccine over the course of 1 year did not result in plasma HIV‐1 RNA rebound nor significantly alter the HIV‐1 reservoir size regardless of immune status. The median intact HIV‐1 reservoir size was 53 (IQR 34–193) copies/million CD4 + T‐cells at baseline and 86 (34–268) and 138 (33–334) 3 months after the second and third dose, respectively ( p > 0.38). We found no correlation between changes in VL or HIV‐1 reservoir size and the anti‐SARS‐CoV‐2‐Spike levels, Spike‐specific CD4 + T‐cells, CD4 + /CD8 + ratio, nadir or CD4 + T‐cell count. However, the intact reservoir size negatively correlated with CD4 + T‐cell count, CD4 + /CD8 + ratio and nadir CD4 + T‐cell count. Conclusions Our findings show that three doses of SARS‐CoV‐2 mRNA vaccine did not affect the VL or HIV reservoir size regardless of immune status, supporting their safety in people with HIV. Notably, a higher CD4 + T‐cell count correlated with a reduced intact HIV‐1 reservoir size.