Vaccine coverage for recommended vaccines among splenectomised patients in Apulia, South Italy: A retrospective cohort study

Abstract

Objective Splenectomised/asplenic patients have a 10-50 fold higher risk than the general population of developing overwhelming postsplenectomy infection. To control this risk, these patients have to receive a specific immunisation schedule, before or in the 2 weeks after the surgical intervention. The study aims to estimate vaccine coverage (VC) for recommended vaccines among splenectomised patients in Apulia (South Italy), and to define the determinants of vaccination uptake in this population. Design Retrospective cohort study. Setting Apulia, Southern Italy. Participants 1576 splenectomised patients. Methods The Apulian regional archive of hospital discharge forms (SDOs) was used to define the splenectomised Apulian inhabitants. The study period went from 2015 to 2020. The vaccination status for Streptococcus pneumoniae (13-valent conjugate anti-pneumococcal vaccine+PPSV23), Haemophilus influenzae type b (Hib; one dose), Neisseria meningitidis ACYW135 (two doses), Neisseria meningitidis B (two doses) and influenza (at least one dose of influenza vaccine before an influenza season after splenectomy) was assessed via data collected from the Regional Immunisation Database (GIAVA). In order to define a subject as fully immunised, we considered the Centers for Diseases Control and Prevention guidelines to define the optimal immunisation status. Results Since 2015, 1576 Apulian inhabitants have undergone splenectomy; the VC for anti-Neisseria meningitidis B vaccine was 30.9%, for anti-Neisseria meningitidis ACYW135 was 27.7%, for anti-Streptococcus pneumoniae was 27.0%, for anti-Hib was 30.1%, and 49.2% received at least one dose of influenza vaccine before an influenza season after splenectomy. None of the patients splenectomised in 2015 and 2016 had received the recommended MenACYW 135 and PPSV23 booster doses 5 years after completing the basal cycles. Conclusions The results of our study highlight low VC values among Apulian splenectomised patients. The task of public health institutions is to implement new strategies aimed at increasing VC in this population, implementing educational measures for patients and families, training for general practitioners and specialists, and ad hoc communication campaigns.