Understanding the decline in HPV vaccination in Colombia: A population-based analysis of girls and parents in early rollout cohorts.

Many countries in the world are facing challenges to reach the WHO proposed target of HPV vaccination of 90 % of girls by the age of 15. A population-based cross-sectional survey was conducted in Manizales, Colombia to identify sociodemographic factors and components of the health belief model related to HPV vaccination in the 2003, 2004, and 2005 birth cohorts of girls and their parents targeted by the national HPV vaccination program in 2012, 2013, and 2014. Complementary log-log generalized linear models were used to obtain adjusted Prevalence Ratios (aPR) and 95 % confidence intervals (CI). A lower prevalence of HPV vaccination was observed in girls of the 2004 (aPR 0.82; 95 % CI 0.71-0.92) and 2005 (aPR 0.61; 95 % CI 0.52-0.71) cohorts compared to the 2003 cohort. The higher scores of perceived benefits by girls (aPR 1.06; 95 % CI 1.05-1.08) or their parents (aPR 1.05; 95 % CI 1.03-1.06) were associated to a higher prevalence of HPV vaccination of the girls. Conversely, this prevalence decreased with perceived barriers by girls (aPR 0.94; 95 % CI 0.91-0.96) and parents (aPR 0.91; 95 % CI 0.88-0.94). Parent's education lower attainment, lower socioeconomic stratum, and subsidized (public) health insurance were related to decreased likelihood of HPV vaccination. The results suggest that campaigns for HPV vaccination require effective education strategies to improve public perception of the vaccine's safety and benefits. Decision-makers and implementers must address also other social determinants such as disparities in access to education by parents, the SES, and the type of health insurance to improve HPV vaccination coverage.