![[ Visit Client Website ]](images/banner.png)
BACKGROUND: Hepatitis A virus (HAV) infections are reportable by law in New York City (NYC), and, in 2006, electronic laboratory reporting for hepatitis A was mandated. Diagnostic tests for HAV lack specificity, which can lead to false positives. In 2006, the Advisory Committee on Immunization Practices (ACIP) recommended all children receive hepatitis A vaccine as part of routine immunizations at 12 months.
METHODS: Clinicians and laboratories are required to report patients who have positive HAV tests. All reports are investigated to determine if they meet the CDC case definition. The NYC Department of Health and Mental Hygiene (DOHMH) routinely investigates all hepatitis A reports, and confirmed cases are interviewed to assess symptoms, risk factors, and occupation. Reports from 2006-2013 were analyzed. We evaluated the surveillance system for timeliness of case investigations, positive predictive value (PPV), and usefulness in identifying contacts to offer post-exposure prophylaxis (PEP).
RESULTS: From 2006-2013, 5,738 reports of hepatitis A were received, and 888 (15%) met the case definition. Of 448 reports received in 2006, 126 (PPV=28%) met the case definition, compared with 838 reports received in 2013 of which 90 (PPV=11%) met the case definition (p<0.0001). The median number of days from report date to patient interview was 0 days for every year except 2011, which was 1 day, and the median number of days from diagnosis date to patient interview declined from 6 days in 2006 to 4 days in 2013. The median age for confirmed cases in 2006 was 23 years versus 31 years in 2013 (p<0.0003); 17% of cases were<10 years in 2006 compared with 3% in 2013. From 2006-2013, PEP was recommended for contacts of 420 cases for which 350 (83%) had at least one contact who was successfully treated for exposure, and a total of 1,243 contacts received PEP.
CONCLUSIONS: The NYC HAV surveillance system is timely with the majority of cases interviewed the day they are reported and useful in allowing for rapid identification and treatment of contacts. The number of confirmed cases reported to DOHMH appears to have decreased, while the age of cases has risen, possibly due to the 2006 vaccine recommendations for children. At the same time, the absolute number of tests and the false positive rate have increased, contributing to greater burden on staff and misdirected resources. Improving the specificity of the test or decreasing testing of patients with low probability of infection could decrease the burden on health departments.