Herpes zoster reactivation in a cohort of people living with HIV vaccinated with recombinant vaccine

Background: People living with HIV (PLWH) have a higher risk of herpes zoster (HZ) reactivation and postherpetic neuralgia (PHN) compared to general population. Our study aims to evaluate prevalence of HZ reactivation and PHN after vaccination with recombinant vaccine (RZV) in a population living with HIV, and to identify risk factors associated with recurrence. Methods: We conducted an observational study, enrolling all PLWH ≥18 years old vaccinated with RZV from January 2022 to December 2023. A questionnaire was proposed to the subjects at least 6 months after vaccination, inquiring about previous history of HZ and PHN, and recurrence after vaccination. We collected demographic characteristics, comorbidities, viro-immunological status, and medications. We performed a descriptive analysis and univariate logistic regressions to investigate risk factors associated with HZ reactivation and PHN persistence. Results: We included 223 subjects. We estimated the prevalence of events among 145 subjects: we recorded 54 subjects with pre-vaccination HZ (prevalence 37.24 % [IC 95 %: 29.36% – 45.65 %]) and 13 with post-vaccination HZ (prevalence 8.97 % [IC 95 %: 4.86 % - 14.84 %]). The prevalence of pre-vaccination PHN was 19.23 % [IC 95 %: 11.18 % - 29.73 %], with mean NRS 6.33 [IC 95 %: 4.9–7.76]; no case of PHN was recorded after vaccination. Evaluating risk factors related to post-vaccination HZ, we didn't find any association with viro-immunological status, clinical history of HIV infection, or concomitant medications. We correlate HZ and age (OR 1.06, CI 95 % 1.01–1.13, p-value 0.031), haematological (OR 9.60, CI 95 % 1.70–49.9, p-value 0.007), oncological (OR 5.36, CI 95 % 1.04–22.8, p-value 0.028), and hepatic comorbidities (OR 3.67, CI 95 % 1.10–12.0, p-value 0.030). Conclusions: This is the first real-world study that highlights the excellent clinical response to RZV, with a low prevalence of HZ reactivation and complete resolution of PHN after the vaccination. Moreover, we identified clinical conditions promoting the recurrence HZ after vaccination.