Frequent detection of acute primary HIV infection in men in Malawi

BACKGROUND: Acute (antibody-negative) HIV infection is associated with high transmission potential but is rarely recognized. DESIGN: Cross-sectional study. METHODS: We examined the prevalence and predictors of acute HIV infection among 1361 consecutive male outpatients attending sexually transmitted disease (STD; n = 929) and dermatology (n = 432) clinics in Lilongwe, Malawi. Serum specimens negative for HIV antibodies were screened by HIV RNA PCR using a highly specific pooling/resolution testing algorithm. RESULTS: Five-hundred and fifty-three men (40.6%) were HIV antibody positive and 24 (1.8%) had acute HIV infection; 23 of 24 acutely infected men were from the STD clinic, where they represented 4.5% of all HIV antibody-negative men and 5.0% of all HIV infections. HIV RNA levels for acutely infected men were significantly higher median (interquartile range), 6.10 (5.19-6.54) log10 HIV RNA copies/ml than for 58 HIV antibody-positive men 4.42 (3.91-4.95) log10 copies/ml; P < 0.0001. The factor most strongly associated with acute HIV infection was STD clinic attendance: (odds ratio, 15.2; 95% confidence interval, 2.04-113.0). In multivariate analysis considering only STD patients, factors associated with acute HIV infection included inguinal adenopathy, genital ulceration and age 24-26 years, the age stratum associated with peak incidence of HIV infection among Malawian men. CONCLUSIONS: Traditional HIV antibody tests alone are not sufficient to exclude HIV infection among men with acute STD in Malawi due to a surprising proportion of acute HIV infections in this population. Alternative screening methods are required for diagnosis of acute HIV infection; such screening could be important for research and for prevention of the sexual transmission of HIV in select populations.