Impact of HPV Vaccination on Prevention of Cervical HPV Infection in Sikkim, India

Study Overview
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Brief Summary
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This project aims is to monitor the effectiveness of HPV vaccination in real-word conditions, at least 7 years after initiation of HPV vaccination in Sikkim. This study would give an opportunity to provide rapid feedback to the Indian public health authorities about the impact of the HPV vaccine.

Detailed Description
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The investigators would like to estimate the prevalence of HPV infections based on cervical samples collected from the Sikkimese women aged 18 to 22 years at baseline (i.e. when the study participants are expected to have no benefit of vaccination) and seven years after the launch of the HPV vaccination programme, by which time the initial vaccinated cohorts will be aged 18 to 22 years and many of them will be sexually active. If the vaccination programme continues with the current high coverage rate, the cohort of women in the second age group are expected to be protected due to herd immunity, irrespective of whether any individual woman receives the vaccine or not. Overall effectiveness to protect women aged 18-22 years against targeted and non-targeted HPV infections will be monitored through repeated cervical sample -based surveys.

Official Title
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Assessing the Population Level Impact of HPV Vaccination on Prevention of Cervical HPV Infection in Sikkim, India

Conditions
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Cervical Cancer

Intervention / Treatment
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* Biological: The study being observational in nature, there is no intervention. The investigators will only collect cervical samples from married women within a specified age range at different intervals.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women aged 18 to 22 years, resident of Sikkim and married. Pregnancy will not be considered as exclusion criteria. Sample collection should be avoided during active menstruation. Exclusion Criteria: Women who do not provide written consent Women who are not able to cooperate in collection of cervical cell sample or respond to questions due to any acute or severe mental and physical illnesses. Women who had undergone hysterectomy. Vaccinated in research project

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 22 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Biological: The study being observational in nature, there is no intervention. The investigators will only collect cervical samples from married women within a specified age range at different intervals.|Women will be approached one time only, when they will attend the gynecology out-patients department for various reasons. After signing the informed consent, the participants will fill in a risk factor questionnaire to study the socio-demographic information, sexual history and HPV vaccination history and the determinent of HPV infection. The questionnaire will be administered by a trained social worker or nurse. A gynecologist will collect cervical cells from the participant's cervix during a gynecological examination. The cervical specimen will be examined for presence of specific HPV genotypes and Chlamydia infection.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The reduction in the point prevalence of genotype-specific HPV infection in women within 7 years of initiation of HPV vaccination compared to that at baseline | The investigators will estimate difference in the prevalence of genotype-specific HPV infection based on cervical samples collected from the married women aged 18 to 22 years at baseline (in the year 2020-21) and again in the year 2025-26 (seven years after the initiation of the HPV vaccination program). | 7 years | 
| The difference in the point prevalence of chlamydia trachomatis infection in women within 7 years of initiation of HPV vaccination compared to that at baseline | The investigators will estimate difference in the prevalence of chlamydia trachomatis infection based on cervical samples collected from the married women aged 18 to 22 years at baseline (in the year 2020-21) and again in the year 2025-26 (seven years after the initiation of the HPV vaccination program). The estimate will allow the investigators to understand any change in the background risk of sexually transmitted infection in the population over time. | 7 years |