Primary HIV Infection

Primary HIV infection is the early stage of HIV infection spanning the first 6 months after acquisition, from initial infection and seroconversion illness through to the setpoint viral load. It includes both the symptomatic acute illness and the asymptomatic phase of recent infection.

• Viral load is very high early, so people with recent infection transmit the virus more efficiently, accounting for a large share of onward spread.
• Rapid antiretroviral therapy limits viral reservoir size, preserves CD4 cells and decreases transmission.

Many people are asymptomatic; others have fever, pharyngitis, rash, lymphadenopathy, headache, myalgia, mouth ulcers, diarrhoea and weight loss lasting 1 to 3 weeks.

• Rash: non itchy maculopapular, upper trunk and face, sometimes palms and soles.
• Differential diagnosis: malaria, dengue, infectious mononucleosis, secondary syphilis, rubella, measles, hepatitis A or B, CMV, typhoid, brucellosis, toxoplasmosis, drug reaction, adult onset Still disease.
• Complications: opportunistic infection during the early CD4 dip, neurological syndromes, onward transmission, vertical transmission in pregnancy, rapid progression in some, drug resistance transmitted from the source.

Recent infection is shown by a positive HIV RNA or p24 antigen with absent, weak or evolving antibodies.

• Fourth generation test, HIV RNA PCR, repeat antibody at 4 weeks and 3 months.
• Rapid antibody tests: a negative result with high suspicion does not exclude infection; retest in 2 to 4 weeks.
• Baseline CD4, viral load, resistance genotype, full blood count, creatinine, liver enzymes, hepatitis B and C, syphilis serology, tuberculosis screen, pregnancy test, STI screening.

Treat immediately, identify contacts, prevent transmission.

• Supportive: post-test counselling and psychological support, safer sex, partner notification, avoid donating blood, reproductive counselling, address stigma and mental health, vaccination (hepatitis B, hepatitis A, HPV, pneumococcal) when appropriate.
• Pharmacological: tenofovir disoproxil fumarate 300 mg, lamivudine 300 mg and dolutegravir 50 mg once daily, started on the day of diagnosis or within 7 days. Cotrimoxazole 960 mg daily if CD4 under 350 or symptomatic. Isoniazid preventive therapy (isoniazid 300 mg daily with pyridoxine 25 mg daily for 6 months) after excluding active tuberculosis. Symptomatic relief with paracetamol 1 g four times daily.
• Procedures: none routine; lumbar puncture for meningism.
• Special groups: pregnancy, immediate treatment to reduce vertical transmission (viral load suppressed by delivery, infant prophylaxis with nevirapine syrup 2 mg/kg daily for 6 to 12 weeks by risk); breastfeeding mothers, continue breastfeeding on suppressive therapy; partners of people with recent infection, offer HIV testing and pre exposure prophylaxis; adolescents, youth friendly services.
• Red flags: neurological symptoms, severe mucosal ulceration, persistent vomiting, pregnancy, CD4 under 200, suspected drug resistance.
• Follow-up: viral load at 1 and 3 months then every 6 months until suppressed; undetectable viral load means no sexual transmission; monitor adherence and side effects.