# Meningococcal Vaccination in High-Risk Patients: A Systematic Approach to Evaluating Coverage and Patient Catch-Up Through Healthcare Databases

## TL;DR

This study uses healthcare databases to find high-risk patients for meningococcal disease and assess their vaccination coverage, finding significant gaps in protection.

## Contribution

A systematic database approach using R-coded algorithms to identify and evaluate vaccination coverage in high-risk IMD patients.

## Key findings

- Only 35.6% of high-risk patients received one dose of MenB vaccine, and 31.8% received two doses.
- Vaccination rates were lowest (<10%) in patients with properdin-complement deficiencies.
- Coverage was significantly lower for conditions diagnosed before immunization guidelines were recommended.

## Abstract

Background: Invasive meningococcal disease (IMD) can lead to severe and fatal outcomes. Vaccines against meningococcus (serogroups B, MenB; or ACWY, MenACWY) are recommended for patients at high risk of developing IMD. Our aim was to identify high-risk patients through a systematic search of medical codes and to evaluate vaccination coverage by high-risk group. Methods: An observational retrospective study was conducted in patients discharged at Reina Sofía University Hospital (Cordoba, Spain) from 1 January 2000, to 31 December 2023. Selection of high-risk patients was conducted through national administrative and clinical databases and vaccination coverage was determined through the Andalusian electronic vaccine database. Vaccine coverages of MenB and MenACWY were calculated within risk groups. Finally, bivariate analyses were conducted to assess the potential association between coverage, sex, and the year of admission. Results: A total of 2689 patients with 2710 high-risk conditions for IMD were identified from the databases searched. Of the 1755 requiring MenB vaccination, only 624 (35.6%) had received one dose and 558 (31.8%) two doses. Of the 2710 requiring MenACWY vaccination, only 784 (28.9%) had received one dose and 520 (19.2%) two doses. Patients with properdin-complement deficiencies showed the lowest vaccination rates (<10%). For the rest of the high-risk groups, vaccination coverages were significantly lower when the condition was diagnosed before the immunization guideline recommendations (p < 0.001). Conclusions: The identification of high-risk patients through databases using R-coded algorithms is both feasible and effective for identifying and catching-up patients for vaccination. The population at risk of IMD lacks adequate meningococcal vaccination coverage. Our methodology can serve to identify patients in other regions and for different vaccines.