Safety of the adjuvanted herpes zoster subunit vaccine in people over 18 years of age living with HIV: A phase 4 multicentre study.

In early 2022, Spain initiated the use of the adjuvanted recombinant subunit herpes zoster vaccine (HZ/su), following recommendations from the Spanish National Immunization Technical Advisory Group (NITAG). Although vaccine safety data from spontaneous adverse event (AE) reporting exists, real-world data (RWD) remains limited, particularly for people living with HIV (PLWH), a population at higher risk for herpes zoster. This study aimed to evaluate the frequency, severity, and duration of AEs in PLWH receiving the HZ/su vaccine, as well as their potential impact on adherence to the vaccination schedule. A prospective, observational multicentre study was conducted to actively monitor AEs occurring within 10 days after administration of either HZ/su vaccine dose. A total of 237 PLWH were enrolled. Of these, 82.7% reported at least one AE after either dose, although grade 3 events were rare. Notably, 99.6% of participants completed the two-dose schedule, suggesting high adherence despite the reactogenicity observed. No unexpected adverse reactions beyond those documented in the vaccine's technical data sheet were identified. Statistical analysis showed no significant difference in the mean number of days between the first and second doses for those who did or did not experience AEs after the second dose. Additionally, none of the demographic or clinical variables studied were associated with an increased likelihood of experiencing adverse events. Overall, the study revealed a favorable safety and tolerability profile for the HZ/su vaccine among PLWH, along with excellent adherence to the vaccination schedule. These findings provide reassuring evidence supporting the use of HZ/su vaccination in this population and contribute valuable RWD to inform clinical decision-making and improve patient communication regarding vaccine safety.