acute HCV infection. Until the quality of the data collected has improved, reports should clearly indicate the limitations of the data. For example,

• Trends in acute HBV and HCV infections should be interpreted with caution because of systematically missing cases that represent the burden of disease in particular risk groups.

• Discussions of data on acute HBV and HCV infections should reflect the issue of the large number of chronic infections to ensure appropriate understanding of the scope of the problem.

• Reported incidences should be presented as ranges rather than single numbers to reflect the uncertainty of the estimates.

Once core hepatitis B and hepatitis C surveillance activities are well established, supplemental or pilot projects should be tested. CDC should develop and support innovative supplemental surveillance programs.

Supplemental surveillance projects should be funded or conducted by CDC and should include serosurveillance among targeted populations. Serosurveillance projects will provide data for improved estimation of the scope of the problem in underrepresented populations such as certain racial and ethnic groups, and at-risk populations, including institutionalized, homeless, immigrant, and refugee populations. Enhanced surveillance projects should be structured to obtain information in both rural and urban regions of the United States. Serosurveillance programs should be flexible and allow researchers to focus on emerging behavioral risks, for example, in adolescents and young adults and in HIV-positive men who have sex with men (Klevens et al., 2009). Conducting serosurveillance or screening among at-risk populations in correctional facilities may provide opportunities to