SOURCE: Adapted from Chen and Morgan, 2006. Reprinted with permission from Ivyspring International Publisher, copyright 2006.
Identifying Acute Infections
Several factors contribute to the difficulty in identifying acute HBV and HCV infections. Many newly acquired cases are asymptomatic, or they may have symptoms similar to those of other common illnesses and so do not prompt health-care providers to conduct serologic testing for HBV and HCV, or the serologic tests that are conducted are inadequate to distinguish between acute and chronic cases. About 90% of acute HBV infections in children under 5 years of age and 70% of HBV infections in adults are asymptomatic (McMahon et al., 1985); 75–95% of acute HCV infections are asymptomatic (Chen and Morgan, 2006; Guerrant et al., 2001), so few infected patients seek care for the acute illness; and there is a very high probability of underreporting even when care is obtained (Chen and Morgan, 2006; Cox et al., 2005; Hagan et al., 2002). Clinicians