Neutralizing activity and T-cell response after bivalent fifth dose of messenger RNA vaccine in people living with HIV

Objectives: To investigate immunogenicity of SARS-CoV-2 vaccine third booster dose (3BD; fifth dose) with bivalent vaccine original/BA4/5 vaccine in people living with HIV (PLWH).Methods: This is an observational cohort study to evaluate the outcomes of SARS-CoV-2 vaccination (HIV -VAC study). We analyzed microneutralization assay and interferon-& gamma; production in 48 PLWH on antiretro-viral therapy with clusters of differentiation (CD4) count < 200 cell/mm3 and/or previous AIDS according to immunization status: vaccinated PLWH who had a previous SARS-CoV-2 infection (hybrid immuniza-tion, HI) vs those only vaccinated (non-hybrid immunization, nHI) and current CD4 count.Results: After 15 days from its administration (T1), the 3BD bivalent messenger RNA vaccine elicited a statistically significant increase of neutralizing antibodies (nAbs) geometric mean titers from T0 to T1 against W-D614G (fold increase 4.8; P < 0.0 0 01), BA.5 (8.6 P < 0.0 0 01), BQ.1.1 (6.4, P < 0.0 0 01) and XBB.1 (6.5, P < 0.0 0 01). When compared to BA.5, nAbs geometric mean titers against BQ.1.1 and XBB.1 decreased by 3.5 and 4.1-fold, respectively. After controlling for age, years from AIDS diagnosis, CD4 count at admin-istration and CD4 count nadir, the fold change reduction in nAbs response to other variants of concerns as compared to BA.1, was larger in participants with HI vs those nHI: 0.59 lower (95% confidence interval 0.36-0.97, P = 0.04) for BQ.1.1 and 0.67 lower (95% confidence interval: 0.47-0.96, P = 0.03) for XBB.1. In contrast, the analysis carried little evidence for an association between current CD4 count and response to the fifth dose of bivalent vaccine. Furthermore, cell-mediated immunity remained stable.Conclusion: Our data support the current recommendation of offering bivalent mRNA vaccine booster doses to PLWH with low CD4 count or previous AIDS at first vaccination, especially in those who never previously acquired SARS-CoV-2 and regardless of current CD4 count.& COPY; 2023 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )