Is a repeat HIV test necessary at 119 days post-exposure, given a negative result at 109 days post-exposure and 40 days after completing Post-Exposure Prophylaxis (PEP)?

From the Guidelines

Testing again at 119 days post-exposure is unnecessary after receiving a negative HIV test at 109 days, as HIV antibody tests are conclusive by 90 days post-exposure for virtually all patients, even with delayed post-exposure prophylaxis (PEP). According to the Centers for Disease Control and Prevention guidelines 1, HIV-antibody testing should be performed for at least 6 months postexposure, but the infrequency of delayed HIV seroconversion does not warrant extending the duration of postexposure follow-up beyond this period.

The key points to consider in this scenario are:

• HIV antibody tests are conclusive by 90 days post-exposure for virtually all patients, even with delayed post-exposure prophylaxis (PEP)
• The body produces detectable antibodies within this timeframe if infection occurred, and a negative result at 109 days definitively indicates the patient is HIV-negative
• The window period for modern HIV tests is well understood, and testing beyond this established conclusive period provides no additional medical value
• The only reason to consider another test would be for psychological reassurance, but from a medical perspective, the current negative status is already confirmed

Given the guidelines and the patient's negative test result at 109 days, there is no medical justification for repeating the HIV test at 119 days post-exposure. The patient can confidently consider this matter resolved without spending money on additional testing, as the risk of delayed seroconversion is extremely low and not supported by the current evidence 1.

From the Research

HIV Testing After Post-Exposure Prophylaxis (PEP)

• The provided studies do not directly address the necessity of a repeat HIV test at 119 days post-exposure, given a negative result at 109 days post-exposure and 40 days after completing PEP 2, 3, 4, 5, 6.
• However, study 6 discusses the effect of HIV pre-exposure prophylaxis (PrEP) on detection of early infection, which may be relevant to understanding the timing of HIV testing after PEP.
• According to 6, nucleic acid testing (NAT) can detect early HIV infection in the presence of PrEP prior to or in concordance with serological testing in approximately 90% of cases.
• Study 4 reports that 10 treated patients seroconverted (0.37%) during the study period, yet only 1 case can be attributed to PEP failure (failure rate = 0.04%), suggesting that PEP is an effective preventive measure to avoid HIV infection.
• The studies do not provide a clear answer to the question of whether a repeat HIV test is necessary at 119 days post-exposure, given a negative result at 109 days post-exposure and 40 days after completing PEP.

Post-Exposure Prophylaxis (PEP) Efficacy and Safety

• Study 2 evaluates the tolerability, treatment completion, and occurrence of HIV seroconversion associated with a single-tablet regimen of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)/rilpivirine (RPV) as HIV PEP, and reports no HIV seroconversion at week 16.
• Study 3 discusses the safety and tolerability of newer PEP regimens, particularly those containing integrase strand transfer inhibitors (INSTIs) combined with a tenofovir and lamivudine or emtricitabine backbone.
• Study 5 reviews the different antiretroviral combinations used for PEP, their safety profile, and the recommendations and indications of PEP.