The goal of this observational study is to assess the impact of HPV vaccination on cervical lesions and genital warts in Colombian birth cohorts. The study examines the trends in healthcare services usage related to these conditions, particularly among vaccinated and unvaccinated populations.

The main questions it aims to answer are:

Have health services usage rates for preneoplastic cervical lesions and genital warts decreased among cohorts of girls eligible for HPV vaccination after the vaccine's introduction? Have there been reductions in health services usage for genital warts among male cohorts of the same birth years as vaccinated girls? Researchers will compare health services usage trends between vaccinated and unvaccinated populations, as well as geographical areas with differing levels of HPV vaccination coverage, to evaluate the impact of the HPV vaccination program.

Participants will not be directly involved, as this is a retrospective analysis of existing healthcare records from various national databases, assessing the frequency of healthcare services related to preneoplastic lesions and genital warts, as well as vaccination coverage at national, departmental, and municipal levels.

This study is an observational ecological assessment aimed at evaluating the impact of the HPV vaccination program on the incidence of cervical preneoplastic lesions and genital warts in Colombia. The analysis compares trends in health services usage across different birth cohorts of girls and boys, exposed and unexposed to the HPV vaccine, using secondary data sources such as the National Health Service Records (UPC) and individual healthcare provision records (RIPS).

The study will employ a retrospective time-series analysis, assessing the frequency of healthcare encounters related to the targeted conditions (genital warts and preneoplastic lesions) by birth cohort and vaccination status. The primary objective is to determine whether there has been a significant reduction in healthcare service use for these conditions following the introduction of the HPV vaccine in 2012.

Secondary objectives include evaluating geographical variations in HPV vaccine coverage at the departmental and municipal levels and their association with the trends in healthcare service usage. This will help ascertain if higher vaccine coverage corresponds to lower rates of genital warts and preneoplastic cervical lesions.

The analysis will rely on both temporal (longitudinal) and geographical (cross-sectional) comparisons. Temporal trends will examine changes before and after the vaccine's introduction, while geographical analysis will compare regions based on varying vaccination coverage levels. Exposure will be categorized according to birth cohort (girls born between 1996 and 2003) and vaccination rates in different geographical areas.

The data analysis will include calculating the average annual rates of healthcare service utilization for both genital warts and preneoplastic lesions, stratified by sex, age group, and region. Statistical methods such as incidence rate ratios (IRRs) and 95% confidence intervals will quantify the association between HPV vaccination and healthcare service usage. The study will also assess potential biases, including information bias due to variability in diagnosis and reporting practices across different health service providers.

By utilizing existing records and implementing robust statistical approaches, the study aims to contribute valuable insights into the effectiveness of HPV vaccination in a middle-income country, where cervical cancer prevention strategies are not as comprehensive as in high-income countries.

The study is anticipated to run for one year, with results presented to both scientific audiences and health policy decision-makers to support the optimization of HPV vaccination strategies in Colombia.

Inclusion Criteria:

• Participants must be born between 1996 and 2003 (for vaccinated cohorts).
• Participants born before 1996 (for unvaccinated cohorts) may be included as control groups.
• Participants must have healthcare service records available for analysis related to genital warts or preneoplastic cervical lesions.
• Participants must have received or not received the HPV vaccine, according to the national immunization program records.
• Data must be available for individuals from regions with documented HPV vaccination coverage rates (departments or municipalities).

Exclusion Criteria:

• Participants without available healthcare service records for genital warts or preneoplastic cervical lesions.
• Participants with incomplete or inaccurate vaccination records.
• Participants not born within the specified birth cohort ranges (i.e., after 2003 or before 1996).
• Individuals from regions without accessible data on HPV vaccination coverage.

The study population consists of individuals from various regions of Colombia, specifically focusing on birth cohorts from 1996 to 2003 for vaccinated groups and cohorts born before 1996 for unvaccinated groups. Participants are drawn from nationwide healthcare service utilization records (UPC and RIPS databases) and HPV vaccination records maintained by the national immunization program. The population includes both males and females, with data sourced from both urban and rural areas, covering all geographical regions with documented HPV vaccination coverage.