STI Screening and Prevention

Epidemiology & Burden - India's Silent Battle

• India faces a substantial STI burden, largely under-reported due to social stigma.
• Prevalent STIs: Genital Herpes (HSV), HPV, Chlamydia, Gonorrhea, Syphilis, Trichomoniasis, HIV.
• High-risk groups: Adolescents & young adults (15-29 yrs), Female Sex Workers (FSWs), Men who have Sex with Men (MSM), Injecting Drug Users (IDUs).
• Untreated STIs cause: Pelvic Inflammatory Disease (PID), infertility, ectopic pregnancy, certain cancers (e.g., cervical), adverse pregnancy outcomes, ↑HIV transmission.
• National AIDS Control Programme (NACP) spearheads surveillance and response efforts.

⭐ NACP Phase V (2021-26) targets elimination of vertical transmission of HIV & Syphilis in India.

Screening Principles - Detect & Defend

• Goal: Early detection of STIs to interrupt transmission, prevent sequelae (e.g., infertility, cancer), and reduce individual morbidity.
• WHO Screening Criteria (Adapted):
  • Important health problem.
  • Accepted treatment.
  • Diagnostic/treatment facilities.
  • Recognizable early stage.
  • Suitable & acceptable test.
  • Natural history understood.
  • Cost-effective.
• Key Strategies & Components:
  • Targeted Screening: Focus on high-risk populations (e.g., MSM, IVDU, multiple partners, CSWs, attendees of STI clinics, pregnant women).
  • Counselling: Essential pre-test (informed consent, risk reduction) & post-test (results, implications, partner management).
  • 📌 The 5 P's of Sexual History: Partners, Practices, Protection from STIs, Past history of STIs, Prevention of pregnancy.
  • Partner Notification & Management (EPT): Crucial to break transmission chain.
  • Vaccination: Primary prevention (e.g., HPV, Hepatitis B).

⭐ Universal screening for HIV, Syphilis, and HBsAg is recommended for all pregnant women at their first antenatal visit as per NACO guidelines.

Specific STI Screening - Pathogen Patrol

• HIV:
  • 4th gen EIA (p24 Ag + Ab); Rapid tests. Confirm: Western Blot/HIV RNA.
• Syphilis:
  • Non-treponemal (VDRL, RPR) → Treponemal (TPHA, FTA-ABS).

  ⭐ Reverse sequence screening (automated treponemal test first) is increasingly common.

• Gonorrhea (GC) & Chlamydia (CT):
  • NAAT (urine, endocervical/vaginal/urethral swabs) - Gold Standard.
• Hepatitis B (HBV):
  • HBsAg (infection).
  • Anti-HBs (immunity).
  • Total Anti-HBc (exposure).
• Hepatitis C (HCV):
  • Anti-HCV Ab → HCV RNA PCR if positive.
• HPV (Cervical Cancer):
  • Pap Smear: Age 21-29 (q3yrs).
  • Co-testing (Pap + HPV DNA) or HPV DNA alone: Age 30-65 (q5yrs).
• Trichomonas vaginalis:
  • Wet mount; NAAT (preferred).
• Herpes Simplex Virus (HSV):
  • Clinical Dx. Lesion PCR/culture if needed. Type-specific serology (limited screening value).

Prevention Strategies - Shield Up!

• ABC: Abstinence, Be faithful, Condom use.
• Condoms: Consistent & correct use (male/female) ↓ STI risk.
• Vaccination:
  • HPV (Gardasil, Cervarix): Prevents anogenital cancers/warts.
  • Hepatitis B: Prevents HBV infection.
• Partner Management: Notification & treatment (EPT).
• Screening: Regular testing for at-risk individuals.
• Biomedical:
  • PrEP (HIV): Daily Tenofovir/Emtricitabine for high-risk.
  • PEP (HIV): Antiretrovirals <72h post-exposure (ideally <2h).
• Antenatal Screening: Prevents vertical transmission.
• Education: Promote safer sex.

⭐ PEP for HIV should be initiated as early as possible, ideally within 2 hours, but no later than 72 hours post-exposure.

High‑Yield Points - ⚡ Biggest Takeaways

• NAAT is gold standard for Chlamydia & Gonorrhea diagnosis.
• Syphilis screening: VDRL/RPR (non-treponemal), confirm with TPHA/FTA-ABS (treponemal).
• HIV screening: 4th gen ELISA, confirm with Western Blot or HIV RNA PCR.
• HPV vaccine (ages 9-26, up to 45 years) prevents cervical & anogenital cancers.
• Screen all pregnant women & high-risk individuals for Hepatitis B (HBsAg).
• Effective STI control requires partner notification & treatment.
• Consistent condom use remains the cornerstone of STI prevention.