HPV Vaccine & Herd Protection  Ias Banenge

Why in News?

• A large Swedish population-based study shows school-based HPV vaccination provides herd protection, reducing cervical cancer even among unvaccinated women.
• Evidence strengthens the case for including HPV vaccine in India’s Universal Immunisation Programme (UIP).
• Relevant as India is planning school-based HPV vaccination (ages 9–14).

Relevance

GS II – Governance & Social Justice

• Public health policy.
• Universal Immunisation Programme.
• Women’s health.

GS III – Science & Technology / Health

• Preventive healthcare.
• Vaccine science.
• Disease elimination strategies.

Basics: What is HPV?

• Human Papillomavirus (HPV):
  • Sexually transmitted virus.
  • >200 types identified.
  • High-risk strains (notably HPV-16, HPV-18) cause:
    • ~95% of cervical cancer.
• Also linked to:
  • Anal, oropharyngeal, penile cancers.
  • Genital warts (low-risk strains).

Cervical Cancer: India Burden

• 2nd most common cancer among Indian women.
• Annual impact:
  • ~1.25 lakh new cases
  • ~75,000 deaths
• Disproportionately affects:
  • Low-income, low-screening populations.

What is Herd Protection?

• When high vaccination coverage reduces overall virus circulation.
• Protects:
  • Unvaccinated individuals.
• Especially relevant for sexually transmitted infections when transmission chains are disrupted.

Key Findings of the Swedish Study

• Cohort:
  • Women born 1989–2000.
• Vaccination coverage:
  • Rose from 25% → 80% via school-based programmes.
• Results:
  • Significant reduction in precancerous cervical lesions.
  • Even unvaccinated women benefited if community coverage was high.
• Critical thresholds:
  • ≥70% coverage → visible herd effects.
  • ~90% coverage → optimal protection.

Why School-Based Vaccination Works ?

• Early age (9–14):
  • Vaccination before sexual debut → maximum efficacy.
• School-based delivery:
  • Higher coverage.
  • Lower dropout.
  • Equity across socio-economic groups.
• Cost-effective at population scale.

HPV Vaccine: Scientific & Medical Aspects

• Type: Preventive, not therapeutic.
• Effectiveness:
  • Nearly 100% protection against HPV-16/18-related precancerous lesions.
• Limitation:
  • Does not eliminate need for screening (Pap smear / HPV DNA test).
• No proven herd immunity evidence yet in India, but established in:
  • Sweden
  • UK
  • Australia.

India’s Current Position

• Indigenous vaccine:
  • CERVAVAC developed by Serum Institute of India.
• Policy direction:
  • Govt considering routine immunisation inclusion.
  • Proposed age group: 9–14 years.
• Challenges:
  • Awareness gaps.
  • Vaccine hesitancy.
  • Need for adolescent health infrastructure.

Public Health Significance

• Shifts cervical cancer control from:
  • Late-stage treatment → Primary prevention.
• Reduces:
  • Screening burden.
  • Long-term oncology costs.
• Aligns with:
  • WHO Cervical Cancer Elimination Strategy:
    • 90% vaccination
    • 70% screening
    • 90% treatment.

Ethical & Social Dimensions

• Gender equity:
  • Protects women disproportionately affected.
• Intergenerational benefit:
  • Herd protection amplifies social returns.
• Justice argument:
  • Preventable cancer → moral obligation of the State.

Takeaway

• High-coverage, school-based HPV vaccination can generate herd protection, making cervical cancer a largely preventable disease and strengthening the case for its inclusion in India’s universal immunisation strategy.