Effects of COVID-19 vaccination and past SARS-CoV-2 infection on subsequent COVID-19 infection in people with HIV.

Background: This study aims to estimate the time-varying effects of primary and booster COVID-19 vaccination and past SARS-CoV-2 infection on subsequent SARS-CoV-2 infection (including new infection and re-infection) in people with HIV (PWH).

Methods: A population-based cohort was retrieved from the integrated statewide HIV electronic health record (EHR) dataset, COVID-19 vaccination dataset, and COVID-19 diagnoses dataset between March 2, 2020 and April 14, 2022. The pre-specified outcome was any SARS-CoV-2 infection. We used Cox regression to estimate the time-varying effects of primary and booster vaccination and past infection on the risks of subsequent SARS-CoV-2 infection.

Results: A total of 18,509 eligible PWH who had documentation of COVID-19 testing or COVID-19 vaccination records were included for analysis. The effectiveness of primary vaccination against infection, compared with being unvaccinated, was relatively low (26.70 %, 95 % CI: 12.10 %, 38.88 %) at two months, while the effectiveness of a booster dose after two months was high (43.53 %, 95 %CI: 27.54 %, 55.99 %), compared with primary vaccination only (e.g., first two doses of Pfizer or Moderna, or the single dose of Janssen). The effectiveness of past COVID-19 infection during Pre-Delta and Delta dominant periods at one month against reinfection was (67.43 %; 95 %CI: 52.74 %, 77.55 %) and (64.57 %; 95 %CI: 1.39 %, 87.27 %), respectively.

Conclusion: Natural immunity conferred from past COVID-19 infection in PWH against reinfection appeared to be higher than vaccine-induced immunity. Boosters were more effective than the primary series alone in preventing subsequent infection.