摘要：Objectives. Because only a fraction of patients with acute viral hepatitis A, B, and C are reported through national surveillance to the Centers for Disease Control and Prevention, we estimated the true numbers. Methods. We applied a simple probabilistic model to estimate the fraction of patients with acute hepatitis A, hepatitis B, and hepatitis C who would have been symptomatic, would have sought health care tests, and would have been reported to health officials in 2011. Results. For hepatitis A, the frequencies of symptoms (85%), care seeking (88%), and reporting (69%) yielded an estimate of 2730 infections (2.0 infections per reported case). For hepatitis B, the frequencies of symptoms (39%), care seeking (88%), and reporting (45%) indicated 18 730 infections (6.5 infections per reported case). For hepatitis C, the frequency of symptoms among injection drug users (13%) and those infected otherwise (48%), proportion seeking care (88%), and percentage reported (53%) indicated 17 100 infections (12.3 infections per reported case). Conclusions. These adjustment factors will allow state and local health authorities to estimate acute hepatitis infections locally and plan prevention activities accordingly. Infection with hepatitis A, B, and C (HAV, HBV, and HCV, respectively) remains a substantial health problem in the United States. 1–3 Chronic HBV 4 and HCV 5 infections currently affect more than 4 million US residents and now account for more deaths than does HIV/AIDS. 6 New HAV and HBV infections have been prevented by the adoption of universal infant vaccination in the United States, but acute infections continue to occur and cause substantial morbidity and mortality. 7 Monitoring case patients with acute HAV, HBV, and HCV is important for several reasons. Identifying individuals with acute infections serves to describe modes of transmission and to detect and control outbreaks. Furthermore, prevention interventions of various types—for example, vaccinating susceptible persons, getting injection drug users into treatment programs, treating persons who are chronically infected to prevent secondary transmission, and preventing complications—require ongoing surveillance and analysis of individuals with acute infections of these 3 viruses. Only a fraction of individuals with acute infections of these 3 viruses are reported eventually to the Centers for Disease Control and Prevention (CDC) in the United States. Barriers to ascertaining and reporting hepatitis infections are many, often reflecting the ability of and resources allotted to the local and state health jurisdictions monitoring them. Natural barriers include the following: most individuals with acute infections of any of the 3 viruses are asymptomatic, only some of those with symptoms seek medical care and testing, and even of those diagnosed, some fraction is not reported or enumerated. Complete reporting of, at a minimum, symptomatic case patients is essential because only by identifying them can interventions be implemented to limit disease in the community. Outbreaks are most often detected from the identification of symptomatic case patients. Currently, the CDC estimates incident HAV, HBV, and HCV infections using reports of case patients to develop adjustments through 3 simple probabilistic multiplier models; however, the methods used to develop the estimating factors (multipliers) are outdated and have never been well described or publicly available. Thus, our goal was to update estimates of the number of individuals with acute infections using 2011 reports of case patients.
