Comparing Risk Behaviour among 14,614 Human Papillomavirus Vaccinated and Unvaccinated Danish Young Women

Human papillomavirus (HPV) is a common sexually transmitted infection. Risky behaviours such as non-condom use, smoking, and binge drinking tend to cluster within the same individuals, increasing their propensity to become infected with HPV. This study aimed to compare risk behaviours, including non-condom use, smoking, and frequent binge drinking, among HPV-vaccinated and unvaccinated young women in Denmark.

Survey data from 14,614 young women aged 15-23 years from the Danish National Youth Study 2019 was used to analyze non-condom use, smoking, and frequent binge drinking. Data on HPV vaccination status was extracted from the Danish Vaccination Register. Associations were assessed using multilevel logistic regression.

In unadjusted analyses, the odds of non-condom use were higher among vaccinated women compared to unvaccinated women (OR: 1.30, 95% CI: 1.09-1.55). Associations were weaker and not statistically significant after adjustment for age. After adjusting for other demographic and socioeconomic factors, smoking, and binge drinking, the odds of non-condom use were 21% higher (95% CI: 1-44%) among vaccinated women than among unvaccinated women. When excluding women in steady relationships using hormonal contraceptives, the association was attenuated and no longer statistically significant. HPV vaccination status was not associated with smoking or binge drinking.

This study showed no clear association between being HPV vaccinated and risk behaviour including, smoking and binge drinking among young women. Non-condom use was more prevalent among the HPV-vaccinated women, but the results suggest that age, relationship status and hormonal contraceptive use may explain a considerable part of the association.