Objective: To better understand the proportions of reported hepatitis B cases in pilot surveillance cites through investigation and laboratory testing.
Methods: To confirm the reported cases of hepatitis B by collecting blood specimen and laboratory testing on HBsAg, IgM of Anti-HBc, Anti-HAV in 18 pilot surveillance counties.
Results: Among 2858 cases of hepatitis B reported in 2006, 23.97% of them were reported as suspected acute cases, 14.87% as acute cases, 20.33% as suspected chronic cases, 34.67% as chronic cases, 4.09% as cirrhosis and 2.06% as HCC. Among 1681 reported hepatitis B cases confirmed by laboratory testing, results showed that 24.16% of them were diagnosed as acute hepatitis B, but only 15.37% were confirmed as acute hepatitis B. Although the proportion confirmed as hepatitis B kept consistent as before, misclassification was found.
Conclusion: In current surveillance system, reported hepatitis B cases were mainly chronic, only up to one third belonged to acute hepatitis B. The reported incidence of hepatitis B did not reflect the real incidence due to misclassification. To better define the burden on hepatitis B disease, it was necessary and urgent to revise the diagnostic criteria and to conduct surveillance on hepatitis B, under separate reporting categories which including acute and chronic cases of the disease.