What is the recommended testing and treatment schedule after exposure to syphilis and Human Immunodeficiency Virus (HIV)?

Retesting Schedule After Syphilis and HIV Exposure

For HIV exposure, retest at 6 weeks, 3 months, and 6 months post-exposure; for syphilis, retest at 4-6 weeks and 3 months if initial tests were negative. 1, 2

HIV Retesting Timeline

The CDC establishes a clear testing algorithm for HIV following exposure:

• Baseline testing at time of initial evaluation 1, 3
• 6 weeks post-exposure 1, 3
• 3 months post-exposure 1, 3
• 6 months post-exposure (final test for standard follow-up) 1, 3

Extended Follow-Up Considerations

• 12-month testing is recommended if you become infected with HCV following exposure to a source coinfected with HIV and HCV 1, 3
• Immediate testing is required if acute retroviral syndrome symptoms develop (fever, rash, lymphadenopathy, pharyngitis) at any point during follow-up, regardless of the scheduled timeline 1, 3

Critical Testing Notes for HIV

• Use HIV antibody testing with EIA as the standard method 1
• Direct virus assays (HIV p24 antigen, HIV RNA) are not recommended for routine follow-up due to high false-positive rates 1
• Testing at 4-6 weeks and 3 months captures the vast majority of seroconversions 1

Syphilis Retesting Timeline

The CDC provides specific guidance for syphilis retesting after exposure:

• Initial testing at time of exposure evaluation 1
• 1-2 weeks post-exposure if initial tests were negative and treatment was not provided (detects organisms that may not have reached sufficient concentrations initially) 1, 2
• 4-6 weeks post-exposure for serologic testing if initial results were negative 1, 2
• 3 months post-exposure for final serologic confirmation 1, 2

Important Syphilis Testing Caveats

• If you provided prophylactic treatment at the initial visit, post-treatment testing should only be conducted if the patient develops symptoms 1
• A follow-up examination at 1-2 months should be considered to evaluate for development of anogenital warts, especially if other STDs were diagnosed 1
• The 2-week window is critical because bacterial STIs like syphilis may not produce sufficient organism concentrations for positive results at initial examination 2

Common Pitfalls to Avoid

• Premature testing leads to false-negative results - testing too soon after exposure will miss infections that haven't reached detectable levels 2
• Single negative test does not rule out infection - the window period necessitates follow-up testing 2
• Don't stop follow-up early - completing the full 6-month HIV testing schedule is essential, as rare delayed seroconversions can occur 1
• Don't use direct HIV virus assays routinely - they increase costs and anxiety without improving detection rates meaningfully 1

Post-Exposure Prophylaxis Context

If post-exposure prophylaxis (PEP) is indicated:

• HIV nPEP should be initiated within 72 hours of exposure and continued for 28 days 1
• The testing schedule remains the same whether or not PEP was administered 1
• Evaluate patients taking PEP within 72 hours and monitor for drug toxicity for at least 2 weeks 1