SARS-CoV-2 mRNA vaccination and short-term changes in viral load and CD4/CD8 T cell counts in people living with HIV

Objectives: To investigate if SARS-CoV-2 mRNA vaccination has an impact on HIV-related viro-immunological parameters. Methods: PWH of the VAXICONA-ORCHESTRA cohort who received ≥1 dose of SARS-CoV-2 mRNA vaccine and for whom paired measures of immuno-virological markers [Viral Load (VL), CD4, CD8 count 1 month before and after a vaccine dose (VD)] were available, were included. Paired t-test and generalized estimating equation linear regression analyses were used to study changes over ± 1 month around the VD. Subgroup analyses were performed. Results: 510 PWH enrolled: median age 55 y (IQR 46-60), CD4 and CD8 count 489(287-719) and 790 (59-1104) cells/mm3. 81% received 3 VDs. After a median of 28 days (3-53) from VD, CD4 count increased by +15 cells/mm3 (SD ±129.7; p=0.001), CD8 by +12 (±250.5; p=0.199), VL decreased by -0.11 log10 (±0.88; p=0.001). Similar results were observed after restricting the analysis to viro-suppressed PWH, with CD4 ≤200/mm3, more than 6 months of ART before VD and after excluding previous COVID-19. Conclusions: A small significant increase in CD4 count and a negligible drop in HIV-RNA were observed. Our findings are consistent with the hypothesis that SARS-CoV-2 mRNA vaccine can prime CD4 T spike specific cells even in the more immuno-compromised PWH.