HIV

HIV Overview

  • Global epidemic affecting over 39.9 million people (2023).

  • Major public health challenge with significant individual, community, and global impact.

Epidemiology

  • Peak morbidity: HIV/AIDS caused high death rates, particularly in sub-Saharan Africa.

  • HIV affects various demographics: 39.9 million globally; significant infections in women, men, and children.

  • 630,000 deaths reported in 2023 from HIV-related causes.

HIV Virology

  • HIV is a lentivirus, part of the retrovirus family; single-stranded RNA virus.

  • High genetic variability due to rapid replication (~10^10 virions daily) and mutation rates (approx. $3 \times 10^{-5}$ per nucleotide).

  • Distinctions between HIV-1 (global prevalence) and HIV-2 (lower infectivity, primarily in West Africa).

Transmission

  • Primary routes: sexual contact (vaginal sex most common), intravenous drug use, blood products, maternal-to-child transmission.

  • Effective prevention includes ART for pregnant women, harm reduction strategies, and safe practices.

Natural History of Infection

  • Three stages: 1) Acute infection, 2) Chronic asymptomatic phase, 3) AIDS with opportunistic infections.

  • CD4 count is critical for monitoring (normal is around 1200 cells/mm³).

Diagnostics

  • Gold standard: Combined HIV-1/2 immunoassay.

  • Rapid/home testing available but less sensitive. Confirmatory tests needed for indeterminate results.

Treatment

  • Holistic management essential; stigma and denial major barriers.

  • ART regimen typically includes two NRTIs plus one from other classes (PI, NNRTI, or integrase inhibitors).

  • Ongoing monitoring for drug effectiveness and resistance required.

Opportunistic Infections (OIs)

  • Commonly seen in individuals with low CD4 count (<200 cells/mm³); include Pneumocystis jiroveci pneumonia and tuberculosis.

  • Management of OIs crucial, as ART significantly reduces incidence.

Preventive Strategies

  • Emphasis on source reduction, awareness, and behavioral changes.

  • PrEP and PEP options available for high-risk populations.