Improved ascertainment of modes of HIV transmission in Ukraine indicates importance of drug injecting and homosexual risk.

The study confirmed the significant degree of misclassification of HIV mode of transmission among registered cases. The role of injecting drug use in HIV transmission is gradually decreasing, but remains high. The proportion of cases related to homosexual transmission is relatively modest, but is rapidly increasing, especially in younger men. Improvements in ascertaining the risk factor information are essential to monitor the epidemic and to guide programmatic response.