Incidence of community-acquired pneumonia and herpes zoster in people with HIV based on CD4-count and age in the current antiretroviral therapy era: a longitudinal cohort study

Background: People with HIV (PWH) using antiretroviral therapy (ART) remain at increased risk for infections such as community-acquired pneumonia (CAP) and herpes zoster (HZ), for which vaccinations are recommended. However, these recommendations do not consider the combined effects of age, CD4 count, and duration of ART on infection risk. We assessed how these factors influence CAP and HZ incidence to better tailor vaccination strategies. Methods: We used data from a nationwide cohort study including all PWH aged ≥18 years in care between 2010 and 2023. All documented CAP and HZ episodes were included, and incidence rates were calculated per 1000 person-years of follow-up (PYFU), stratified by age, CD4 count, and ART duration. Results: Community-acquired pneumonia and herpes zoster incidence rates were highest in PWH with CD4 ≤ 200 cells/µL, ranging from 34 to 107/1000 PYFU for CAP and 9 to 63/1000 PYFU for HZ, depending on age. In those with CD4 ≥ 500 cells/µL and ≥1 year on ART, incidence rates ranged from 5 to 20/1000 PYFU for CAP and 4 to 5/1000 PYFU for HZ, depending on age. Conclusions: Incidence rates are the highest in PWH with CD4 counts ≤200 cells/µL and/or not on ART, whereas PWH with CD4 counts ≥500 and ≥1 year on ART have a risk of CAP and HZ comparable to that of the general population. These findings support aligning vaccine recommendations for PWH on long-term suppressive ART with immune reconstitution with those for the general population, while HIV-specific vaccination strategies may remain most relevant for individuals with virological failure and/or poor immune reconstitution.