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Session 100 Poster Session Molecular Epidemiology Session Time: 4:30-6:30 pm Room 4E-F

760-W. Distinct Patterns of the HIV-1 Epidemic in the People's Republic of China Z. Chen *1, G. Li2, Y. Huang1, X. Zhao1, S. Mei2, L. Ba1, L. Zhang1, D. Ho1, and Y. Cao2 1 Aaron Diamond AIDS Res. Ctr., Rockefeller Univ., New York, NY and 2Natl. Ctr. for AIDS Prevention and Control, Chinese Academy of Preventive Med., Beijing Background: The number of AIDS cases in the People’s Republic of China has increased dramatically since 1999. Because most Chinese patients cannot access HAART, such an increase in AIDS incidence underscores the urgent need to develop an effective vaccine. To gain a better understanding of the current epidemic strains in China for vaccine design, we have characterized HIV-1 strains from selected areas in 9 Chinese provinces since 1999. Methods: HIV-1 p17 and C2V3 regions were amplified, sequenced, and phylogenetically analyzed. For some viruses, full-length env genes or genomes were also studied. Results: Among 96 specimens analyzed thus far, 4 HIV-1 subtypes (A, B, C, and G) were identified. The distribution of various subtypes is closely related to the mode of viral transmission in the geographic regions studied. In Yunnan, Guangxi, and Xinjiang, 3 provinces that account for > 80% of Chinese HIV-1 infections, transmission is largely due to intravenous drug use and is dominated by subtype-C viruses. Further analysis on full-length env genes has revealed a circulating recombinant form (CRF007) that is largely subtype C with small fragments of subtype B. Although Xinjiang in the northwest is geographically distant from Yunnan and Guangxi in the southwest, the viral strains found in these 3 provinces are rather homogeneous, suggesting a common and recent origin of the most prevalent viral subtype in China. In Henan, Hubei and Shanxi provinces, where blood transfusion/contamination is the major mode of transmission, HIV-1 strains identified consist of highly related subtype-B viruses. In Beijing where patients come from diverse backgrounds and locales, the viruses are rather heterogeneous. For example, in 1 hospital alone, 3 different HIV-1 subtypes are found. Conclusions: 4 HIV-1 subtypes have been identified in the People’s Republic of China. The high degree of viral homogeneity observed in the most severely affected provinces indicates a fairly recent outbreak of the virus. The molecular epidemiology that emerges from our study could guide the design, development, and testing of an AIDS vaccine for China.

©2002 9th Conference on Retroviruses and Opportunistic Infections