Durability of tetanus seroprotection in people living with HIV

Objectives: The aim of this study was to estimate the durability of tetanus toxoid specific seroprotection in a cohort of people with HIV (PWH). Design: A cross-sectional study. Methods: PWH with a last date of tetanus toxoid booster available were identified. Tetanus toxoid specific IgG were detected using commercial ELISA kit. Durability of seroprotection was estimated using a linear regression model and analyzed according to the country of birth. The impact of baseline parameters at the time of vaccination (CD4(+) T cell count, viral load, and antiretroviral therapy) was also assessed. Results: One hundred three individuals were included. The median duration between last tetanus toxoid booster and sampling was 5.6years (IQR 2.6-8.9). Using a linear regression model, half-life of tetanus toxoid specific antibody was estimated at 9.9 years [95% confidence interval (95% CI: 5.5-50)] in the whole cohort. Half-life was reduced in individuals born outside Europe: 4.4 years (95% CI: 2.9-8.5). PWH born outside Europe had lower CD4(+) T cell count at the time of immunization and more frequently a CD4(+) T cell count nadir less than 200 cells/mu l before vaccination. Conclusion: PWH born outside Europe have lower half-life of tetanus toxoid specific antibody as compared to previous study performed in the general population. Possible causes include lower nadir or current CD4(+) T cell count or under-immunization status in country of origin before migration. Longer interval of booster vaccination, as recommended in the general population, might not be appropriate in this subgroup of PWH. Copyright (c) 2022 Wolters Kluwer Health, Inc. All rights reserved.