What is the recommended post-exposure prophylaxis (PEP) for an employee who experienced a needlestick exposure and has negative Human Immunodeficiency Virus (HIV) antigens but positive antibodies in their blood test results?

Post-Exposure Prophylaxis for Source Patient with Positive HIV Antibodies

No PEP is indicated for the exposed employee—the source patient is HIV-infected, not the exposed worker. The question describes testing results from the source patient (the person whose blood the employee was exposed to), showing that this individual has established HIV infection (negative antigens but positive antibodies). 1

Critical Clarification: Understanding the Test Results

The blood draw described is from the source patient, not the exposed employee. The results indicate:

• Negative HIV antigens = No acute/early infection markers
• Positive HIV antibodies = Established HIV infection present 1

This confirms the source is HIV-positive with established infection (not acute seroconversion). 1

Recommended Management for the Exposed Employee

Immediate Actions (Within Hours of Exposure)

Initiate PEP for the exposed employee immediately—within 2 hours if possible, no later than 72 hours post-exposure. 1

The specific regimen depends on exposure severity:

• For most needlestick exposures from HIV-positive source: Basic two-drug PEP regimen (typically ZDV + 3TC or emtricitabine + tenofovir) 1
• For high-risk exposures (large-bore hollow needle, deep puncture, visible blood on device, or needle used in source's artery/vein): Expanded three-drug PEP regimen (add protease inhibitor like indinavir or nelfinavir) 1

Determining Source Patient HIV Status Details

Since the source is confirmed HIV-positive, gather additional information to guide PEP selection: 1

• Stage of infection (asymptomatic vs. symptomatic/AIDS)
• CD4+ T-cell count (Class 1: asymptomatic/low viral load <1,500 copies/mL vs. Class 2: symptomatic/high viral load)
• Current antiretroviral therapy and treatment history
• Known drug resistance patterns 1

Do not delay PEP initiation while gathering this information—start immediately and modify the regimen later if needed. 1

PEP Duration and Monitoring

• Administer PEP for 4 weeks if tolerated 1
• Baseline testing of exposed employee: HIV antibody, complete blood count, renal and hepatic function 1
• Toxicity monitoring at 2 weeks: Repeat CBC and renal/hepatic function tests 1
• Reevaluate within 72 hours as additional source information becomes available 1

Follow-Up HIV Testing Schedule for Exposed Employee

The CDC recommends the following testing timeline: 1, 2

• Baseline (at time of exposure)
• 6 weeks post-exposure
• 12 weeks (3 months) post-exposure
• 6 months post-exposure

Extended 12-month follow-up is recommended if the exposed employee becomes infected with HCV following exposure to a source coinfected with HIV and HCV. 1, 2

Critical Testing Considerations

• Use HIV-antibody EIA testing for routine follow-up 1
• Direct virus assays (p24 antigen, HIV RNA) are NOT recommended for routine monitoring due to high false-positive rates and unnecessary anxiety 1
• Exception: Perform HIV testing immediately if the exposed employee develops illness compatible with acute retroviral syndrome, regardless of timeline 1, 2

Common Pitfalls to Avoid

• Never delay PEP while awaiting source patient details—start the basic regimen immediately and adjust later 1
• Do not use direct virus assays routinely—stick with antibody testing except for suspected acute infection 1
• Do not discontinue PEP prematurely—the full 4-week course is essential even if side effects occur (modify regimen with expert consultation rather than stopping) 1
• Animal studies show PEP effectiveness drops significantly after 24-36 hours, but initiation up to 72 hours (or even 1 week for high-risk exposures) should still be considered 1