Session 29Oral Abstract Presentations Topics in Primary HIV Infection Session Day and Time: Thursday 10 - 11 am Presentation Time: 10:45 Room: Ballroom B
154 Frequent Detection of Acute Primary HIV Infection in Men in Malawi: Reconsideration of Counseling and Testing Approaches C. D. Pilcher*1, M. A. Price*1, I. F. Hoffman1, F. E. A. Martinson2, P. N. Kazembe2, J. J. Eron1, W. C. Miller1, S. A. Fiscus1, M. S. Cohen1 1Univ of North Carolina at Chapel Hill and 2Lilongwe Central Hosp, Lilongwe, Malawi
Background: Acute primary HIV infection (PHI) is rarely diagnosed in sub-Saharan Africa despite high HIV incidence.
Methods: We examined the prevalence and predictors of Ab-negative PHI among Malawian men in a cross sectional study. Consecutive male attendees to Lilongwe Central Hospital STD clinic (n = 929) were enrolled with acute urethritis and/or genital ulcer disease (GUD). Additional patients (pts) were enrolled from Dermatology clinic (n = 432). HIV Ab testing used rapid latex agglutination with positives confirmed by ELISA. HIV Ab negative subjects had aliquots of plasma pooled in a 1:10:50 pyramid scheme and screened for HIV RNA using Roche or NucliSens. Confirmatory Ab testing used IgM-sensitive ELISA and WB. PHI was defined as RNA repeatedly > 10K with neg/indeterminate Ab OR RNA repeatedly + with indeterminate Ab. Factors associated with PHI were identified using bivariate analysis and multivariate logistic regression.
Results: Of 1,361 total men enrolled, 553 (40.6%) were HIV Ab+ and 24 (1.8% of the total population) had confirmed PHI; 23 of 24 were STD clinic pts. Viral loads for men with PHI (med [IQR]: 6.10 [5.19, 6.54] log cp/ml HIV RNA) were significantly higher than for 58 HIV Ab+ men (4.42 [3.91, 4.95] log cp/ml; p < 0.0001). The factor most strongly associated with PHI diagnosis was presentation at the STD clinic: (OR 16.5 [95%CI: 2.2, 122.3]). In the STD clinic, 23 PHI cases accounted for 2.5% all pts, 4.5% Ab negative pts, and 5.0% all HIV infections. In multivariate analysis considering only STD pts, significant predictors of having prevalent PHI included first STD (OR 4.96 [1.11, 22.22]); age > 23 (OR 3.54 [1.37, 9.13]); and > secondary school education (2.46 [1.03, 5.84]). Inguinal adenopathy (OR 4.74 [1.97, 11.43]) was an independent predictor but GUD was not significant in multivariate analysis (OR 2.15 [0.86, 5.33]).
Conclusions: Men in Malawi-most particularly those with STD symptoms-have a remarkably high prevalence of acute antibody-negative HIV infection. As a result, antibody tests alone are insufficient to exclude HIV infection in an STD clinic setting (sensitivity < 95%). Counseling HIV/STD co-infected subjects with very high viral loads that they are HIV- in this setting could inadvertently increase transmission. Screening criteria based on risk factors for PHI could be developed to lessen the potential burden of additional testing required to detect acute HIV infections in these settings.
