Influence of socio-economic inequalities and healthcare organisation on HPV vaccination coverage in both sexes in the Campania region: A population-based study between 2006 and 2023.

Abstract

Human papillomavirus (HPV) and hepatitis B vaccinations are the only immunisation programmes that directly prevent cancer. Despite the expansion of universal, gender-neutral HPV programmes, a free and actively offered vaccination does not ensure achievement of coverage targets. We conducted a population-based longitudinal ecological study in the Campania Region, the most populous Region in Southern Italy, to investigate socio-economic deprivation as a barrier to HPV vaccination. The study covered 2006-2023 and the 1997-2011 birth cohorts. Immunisation registry records were linked with demographic data, the 2011 Deprivation Index (DI), and vaccination-centre density, all aggregated at Health District (HD) level. Outcomes were one-dose, full-immunisation, and catch-up coverage (at least one dose after 18 years of age). Mixed-effects linear regression models were fitted with HDs nested within Local Health Authorities (LHAs) as random intercepts. Coverage remained below recommended targets. The highest cohort-specific coverage for one dose, full immunisation and catch-up was, respectively, 68.5% (2005 cohort), 62.2% (2002) and 2.2% (1998) among females, and 41.1% (2007), 29.9% (2007) and 0.6% (1999-2002) among males. Coverage varied across LHAs and HDs, independently of vaccination-centre density. Higher deprivation was associated with lower male one-dose and full-immunisation coverage (Coeff:-1.56 [-2.83|-0.29] and - 1.36 [-2.35|-0.37]). Among females, routine coverage was not associated with deprivation, which instead affected catch-up (Coeff: -0.057 [-0.094|-0.020]). HPV uptake in Campania is shaped by territorial heterogeneity and, for males and for catch-up pathways, by socio-economic inequalities, whereas routine female coverage was not affected by deprivation, supporting the equity value of a universal, actively offered programme and the need for locally tailored strategies.