HIV/AIDS: Epidemiology & Pathogenesis - Viral Vitals
- Virus: Retrovirus (Lentivirus); two ssRNA strands.
- Key Enzymes: Reverse Transcriptase, Integrase, Protease (📌 RIP).
- Proteins: Envelope (gp120 for CD4 binding, gp41 for fusion), Capsid (p24 antigen - early marker).
- Transmission: Sexual, Parenteral (blood), Perinatal (mother-to-child).
- Pathogenesis: Infects CD4+ T-cells, macrophages, dendritic cells → progressive CD4 depletion → immunodeficiency.
- Normal CD4 count: 500-1500 cells/mm³.
- AIDS: CD4 count < 200 cells/mm³ or AIDS-defining illness.
⭐ HIV primarily targets CD4+ T-lymphocytes, leading to their destruction and severe immunodeficiency.

NACP: Phases & Objectives - India's Shield
India's National AIDS Control Programme (NACP) is the cornerstone of its HIV/AIDS response, evolving through several phases:
- Core Objectives:
- Reduce new infections (Prevention).
- Provide comprehensive Care, Support & Treatment (CST).
- Reduce stigma & discrimination.
- Strengthen surveillance & monitoring systems.
⭐ NACP V aims to achieve the 95-95-95 targets: 95% of people living with HIV (PLHIV) know their status, 95% of diagnosed PLHIV receive sustained Antiretroviral Therapy (ART), and 95% of all people receiving ART achieve viral suppression by 2025.
HIV Prevention & Diagnosis - Detect & Protect
- Prevention Pillars:
- Safe Sex: Condom promotion, reduce partners.
- Blood Safety: Mandatory screening of blood products.
- PPTCT: ART for HIV+ pregnant women; infant Nevirapine prophylaxis for 6 weeks.
- Harm Reduction: Needle exchange for IDUs.
- PEP: Start within 72 hrs (ideally <2 hrs), 28-day regimen.
- PrEP: For high-risk individuals.
- Diagnosis:
- Screening: ELISA (4th gen detects p24 Ag & Ab).
- Confirmatory: Western Blot or 2 different rapid tests (serial testing).
- Early Infant Diagnosis (EID): HIV DNA PCR at 6 weeks, 6 months, 12 months.
⭐ Window period for HIV antibody detection is typically 3 weeks to 3 months; 4th gen tests & NAT reduce this.
HIV Treatment & OI Prophylaxis - Treatment Tactics
- ART Initiation:
- "Treat All" policy. Goal: ↓VL, ↑CD4, ↓morbidity/mortality.
- Preferred Regimens (NACO):
- First-line: TLD (Tenofovir 300mg + Lamivudine 300mg + Dolutegravir 50mg).
- Adherence:
- Critical for success (>95%).
- Monitoring:
- Viral Load (VL): Primary efficacy marker. Target < 50 copies/mL. Check at 6, 12 months, then annually.
- CD4 count: Monitors immune recovery. Baseline, then 6-monthly.
- OI Prophylaxis (CD4-guided):
- TB: IPT (6 months) for all (rule out active TB).
- PCP (PJP): CD4 < 200 cells/µL → Cotrimoxazole.
- Toxoplasmosis: CD4 < 100 cells/µL (IgG+) → Cotrimoxazole.
⭐ Dolutegravir (DTG) based regimens are preferred first-line ART due to high efficacy, good tolerability, and high barrier to resistance.
High-Yield Points - ⚡ Biggest Takeaways
- NACO is the apex body for India's HIV/AIDS control program.
- NACP-V (2021-2026) targets UNAIDS 95-95-95 targets by 2025; aims for epidemic elimination by 2030.
- "Test and Treat" policy: ART for all PLHIV, regardless of CD4 count/clinical stage.
- PPTCT program is vital for preventing vertical HIV transmission.
- Targeted Interventions (TIs) focus on High-Risk Groups (HRGs) and vulnerable populations.
- HIV/AIDS Act, 2017 safeguards rights and prohibits discrimination against PLHIV.
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