How can opportunistic infections be prevented in individuals with Human Immunodeficiency Virus (HIV)?

Prevention of Opportunistic Infections in HIV-Infected Individuals

The most effective approach to preventing opportunistic infections in HIV-infected individuals is highly active antiretroviral therapy (HAART), which should be considered for all HIV-infected persons who qualify for such therapy, combined with appropriate chemoprophylaxis based on CD4+ T-lymphocyte counts. 1

Primary Prevention Strategies

1. Antiretroviral Therapy

• HAART is the cornerstone of opportunistic infection prevention as it:
  • Reduces viral load
  • Increases CD4+ T-cell counts
  • Restores immune function
  • Dramatically reduces the incidence of opportunistic infections 1

2. CD4+ Count-Based Prophylaxis

Specific prophylaxis should be initiated based on CD4+ count thresholds:

For CD4+ count <200/μL:

• Primary prophylaxis against Pneumocystis carinii pneumonia (PCP) is mandatory 1
  • First choice: Trimethoprim-sulfamethoxazole (TMP-SMZ) one double-strength tablet daily (AI) 1
  • Alternatives if TMP-SMZ not tolerated:
    • TMP-SMZ one single-strength tablet daily (AI)
    • TMP-SMZ one double-strength tablet three times weekly (BI)
    • Dapsone (BI)
    • Dapsone plus pyrimethamine plus leucovorin (BI)
    • Aerosolized pentamidine via Respirgard II nebulizer (BI) 1

For CD4+ count <100/μL:

• Consider prophylaxis against Mycobacterium avium complex (MAC) 1

For CD4+ count <50/μL:

• Intensify prophylaxis regimens as risk for multiple opportunistic infections increases significantly 1

3. Additional Prophylaxis Indicators

Prophylaxis should also be initiated regardless of CD4+ count in patients with:

• History of oropharyngeal candidiasis (AII)
• Unexplained fever >100°F (37.7°C) for ≥2 weeks (AII)
• History of AIDS-defining illness (BII) 1

Discontinuing and Restarting Prophylaxis

Discontinuing Primary Prophylaxis

• PCP prophylaxis may be discontinued if CD4+ counts increase to >200/μL for at least 3 months in response to HAART 1
• Important caveat: Most experts recommend that prophylaxis be initiated or continued based on the lowest CD4+ count ever recorded, not the current count, until more data are available 1

Restarting Prophylaxis

• Restart prophylaxis if CD4+ count falls below the threshold for specific opportunistic infections 1

Special Populations

Pregnant Women

• Prophylaxis recommendations apply equally to pregnant women 1
• TMP-SMZ remains the recommended agent for PCP prophylaxis during pregnancy 1

Children

• Children born to HIV-infected mothers should receive TMP-SMZ prophylaxis beginning at 4-6 weeks of age 1
• Prophylaxis should be discontinued for children found not to be HIV-infected
• HIV-infected children should continue prophylaxis based on age-specific CD4+ count thresholds 1

Common Pitfalls to Avoid

1. Failing to monitor CD4+ counts regularly: CD4+ counts should be monitored at least every 3 months; when this is not possible, consider initiating prophylaxis at CD4+ counts <250/μL rather than <200/μL 1

2. Discontinuing prophylaxis prematurely: Despite increases in CD4+ counts with HAART, opportunistic infections can still occur, particularly in patients with a history of very low CD4+ count nadirs 2

3. Poor medication adherence: This is the most common reason (30%) for patients presenting with low CD4+ counts despite the availability of HAART 2

4. Overlooking drug interactions: Particularly between rifamycins and antiretroviral drugs 1

5. Ignoring vaccination recommendations: HIV-infected individuals should receive appropriate vaccinations according to specific guidelines for this population 1

By implementing these evidence-based strategies, healthcare providers can significantly reduce the morbidity and mortality associated with opportunistic infections in HIV-infected individuals.