# Improved pertussis vaccine uptake following in-hospital administration among pregnant women living with HIV

## TL;DR

Administering the Tdap vaccine in-hospital significantly increased vaccination rates among pregnant women living with HIV.

## Contribution

In-hospital vaccine administration improved uptake among pregnant women with HIV, confirmed by statistical analysis.

## Key findings

- Vaccine uptake increased from 20% to 78.3% after in-hospital administration was introduced.
- Firth’s penalized logistic regression confirmed the association between in-hospital vaccination and higher uptake.
- The adjusted odds ratio showed a strong independent association between the intervention and vaccine uptake.

## Abstract

Pregnant women living with HIV (PWLHIV) are at increased risk of infectious complications during pregnancy, and HIV-exposed but uninfected women are more susceptible to serious infectious diseases. Therefore, maternal immunization during pregnancy is an essential standard of care for this patient population. However, vaccination during pregnancy is suboptimal among these patients.

This is a single-center retrospective observational study, conducted at the University Hospital Federico II of Naples, Italy. We examined how our Center's vaccination uptake among PWLHIV changed after the introduction of in-hospital vaccine administration. To account for the small sample size and assess the robustness of the findings, Firth’s penalized logistic regression was performed as a sensitivity analysis.

Between January 2021 and December 2024, 41 PWLHIV have been referred to the Regional Referral Centre for HIV in Pregnancy. Out of 38 eligible patients, 21 received the Tdap vaccine, resulting in an overall uptake of 55.3%. Following the introduction of in-hospital vaccine administration in January 2023, we observed a significant increase in pertussis-containing vaccine uptake among PWLHIV. Vaccine uptake increased from 20% (January 2021–December 2022) to 78.3% after the introduction of in-hospital vaccine administration (January 2023–December 2024), (p < 0.001). The sensitivity analysis using Firth’s penalized logistic regression confirmed the independent association between in-hospital vaccination and vaccine uptake (adjusted OR 11.45; 95% CI 2.45–68.32; p < 0.001).

We observed improved vaccine uptake after introducing vaccine administration within the hospital setting. We believe that this strategy might significantly improve vaccine administration among PWLHIV.