What are the recommendations for yellow fever vaccination in a patient with well-controlled Human Immunodeficiency Virus (HIV) on Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide), with undetectable HIV RNA and a CD4 count of 300 cells/mm^3?

Yellow Fever Vaccination Recommendation for HIV-Positive Patient with CD4 300

This patient with well-controlled HIV (undetectable viral load, CD4 300) can receive yellow fever vaccine if traveling to an endemic area, but should be monitored closely post-vaccination and may benefit from serologic testing to confirm adequate antibody response. 1

Risk Stratification Based on CD4 Count

This patient falls into the moderate immunosuppression category (CD4 200-499 cells/mm³), which the CDC classifies as a precaution rather than a contraindication for yellow fever vaccination. 1, 2

• Contraindication threshold: CD4 <200 cells/mm³ or symptomatic HIV infection 2
• Safe vaccination threshold: CD4 ≥500 cells/mm³ (no precautions) 2
• This patient's CD4 of 300: Falls in the middle zone where vaccination "can be considered" 2, 1

Key Favorable Factors in This Case

The patient's virologic suppression (HIV RNA <20) on effective antiretroviral therapy is a critical positive factor that supports vaccination. 1

• Higher CD4 counts and suppressed HIV RNA are key determinants for developing protective antibody titers 3, 4
• Current CD4 count and viral suppression status (if stable over 3 months) should guide decision-making, not historical CD4 nadir 2
• Multiple studies of approximately 450 HIV-infected patients with moderate immunosuppression reported no serious adverse events 2, 1

Expected Vaccine Response

Reduced but adequate immunogenicity should be anticipated in this patient:

• Only 83% of HIV-infected adults with CD4 >200 developed protective antibodies versus 97% of HIV-negative controls 2
• In one study, 92% of HIV-infected patients on antiretroviral therapy achieved adequate neutralizing titers 4
• Seroconversion may occur more slowly than in immunocompetent individuals 5

Critical Action Items

1. Assess True Need for Vaccination

• If travel is to a yellow fever endemic area with actual disease risk: Proceed with vaccination 2, 1
• If vaccination is only for entry requirements without true exposure risk: Consider obtaining a medical waiver instead 2, 1

2. Post-Vaccination Serologic Testing

Strongly consider measuring neutralizing antibody response 4-6 weeks after vaccination to confirm adequate immunity. 2, 1

• Contact state health department or CDC (1-970-221-6400) to arrange serologic testing 2, 1
• This is particularly important given the 17% failure rate in this population 2

3. Close Monitoring

Monitor closely for adverse events post-vaccination and file VAERS report if any occur. 2, 1

Important Caveat: Biktarvy Consideration

There is theoretical concern about the integrase inhibitor component of Biktarvy, though this is primarily relevant to CCR5 antagonists (maraviroc), not integrase inhibitors like bictegravir. 2

• One case of yellow fever vaccine-associated viscerotropic disease occurred in a patient with CCR5 polymorphism 2
• Further research is needed, but this should not preclude vaccination in this patient on Biktarvy 2

Dosing

Use standard single-dose vaccination—there is no evidence supporting double-dose yellow fever vaccination in immunocompromised individuals. 1

Critical Pitfall to Avoid

Do not vaccinate if the patient has any AIDS-defining illness or symptomatic HIV manifestations, even with CD4 >200, as this represents a contraindication. 2

• One fatal case of myeloencephalitis occurred in an asymptomatic HIV patient with high viral load and low CD4 count who was vaccinated 6
• This underscores the importance of confirmed viral suppression and adequate CD4 count 6