Antibody Responses After BA.5/BF.7 Breakthrough Infection in People Living with HIV

Suppressive ART enables PLWH to mount hybrid immunity-conferred by vaccination followed by BF.7 or BA.4/5 breakthrough infection-with neutralizing and ADCC responses comparable to HIV-negative individuals, and significantly exceeding those of unvaccinated PLWH with primary infection. This underscores the critical role of vaccination in establishing effective hybrid immunity in this population. However, we observed immunological imprinting, with higher titers against ancestral strains than against infecting variants, and substantial escape by emerging sublineages XDV, KP.2, and KP.3 across all groups. These findings support prioritizing updated variant-containing vaccines for HIV-positive populations and reinforce the essential role of vaccination in this vulnerable group.