HPV vaccine shows herd protection for cervical cancer, Pg16

Key Highlights:

• Swedish data shows HPV vaccination programs can reduce cancerous lesions even in unvaccinated women, demonstrating a herd-protective effect.
• Cervical cancer is the second most common cancer in Indian women, affecting 1.25 lakh and causing 75,000 deaths annually.
• A Swedish study showed that high vaccination coverage (80%) in the 1999-2000 cohort led to a reduction in pre-cancerous lesions even in unvaccinated women.
• India is planning a school-based HPV vaccination program for girls aged 9-14 years, aiming for a vaccination coverage of at least 70%.

Detailed Insights:

• The Swedish study examined pre-cancerous lesions in unvaccinated women across four cohorts born between 1989 and 2000, noting increased vaccination coverage over time.
• Unvaccinated women born in 1999-2000, who grew up with vaccinated peers, had about half the risk of developing serious precancerous cervical changes.
• Experts suggest that the impact of India's vaccination program will first be seen in a reduction of genital warts, followed by a decrease in cancer incidence.
• High vaccination coverage can reduce the need for triage testing like pap smears, HPV tests, and CIN tests, as HPV incidence decreases.
• Over 95% of cervical cancer cases are linked to persistent infection with high-risk strains of HPV, with at least 14 HPV types identified as potentially carcinogenic.

Key Concepts Involved:

• HPV (Human Papillomavirus): A group of related viruses, some of which can cause cancer.
• Herd Immunity: Protection from a disease conferred to unvaccinated individuals when a significant portion of the population is vaccinated.
• Cervical Cancer: A type of cancer that occurs in the cells of the cervix, often caused by HPV infection.