Trends in the total numbers of HBV and HCV carriers in Japan from 2000 to 2011

Abstract

Summary We estimated the total number of undiagnosed HBV and HCV carriers and patients with hepatitis virus‐related disease in Japan according to 6 different groups classified by their natural histories during 2011. In 2011, the total number of carriers and patients infected with HBV or HCV was estimated according to 6 groups using government reports and reports from the hepatitis epidemiology research group of The Ministry of Health, Labor and Welfare in Japan. In 2011, the total number of hepatitis virus carriers was estimated to be 2 090 128‐2 840 128 in which the estimated number of undiagnosed HCV and HBV carriers was 776 826 (HBV: 481 470; HCV: 295 356). The total number of treated patients, as either inpatients or outpatients, was estimated to be 811588 (HBV: 303 366; HCV: 520 600) in 2011. It is presumed that many carriers shirk consultation for many reasons, such as patients’ misunderstanding, lack of awareness and forgetfulness of their positive status. The numbers of infected patients who did not seek treatment increased gradually to 501 714‐1 251 714 (HBV: 333 791‐483 791; HCV: 167 923‐767 923) in 2011. Compared to 2000, the number of undiagnosed carriers was significantly reduced in 2011 probably because of the well‐organized, effective national hepatitis virus screening system that has been launched by the Japanese government since 2002. Moreover, the increase in the number of untreated persons who are aware of their positive status shows that more effort should be invested in improving the referral system from screening centres to core hospitals.

Countermeasures against viral hepatitis B and C in Japan: An epidemiological point of view

“…The single peak of high prevalence occurred in the same birth‐year group as previous studies (Fig. ) …”

“…This long journey of countermeasures against viral hepatitis in Japan has resulted in increasing numbers of people diagnosed with hepatitis virus infection and the provision of easily accessible antiviral therapy for chronic persistent infection . Many large‐scale epidemiological or clinicopathological studies have been undertaken to explore the relationship between persistent infection of hepatitis virus and liver diseases, including HCC, the natural course of patients persistently infected with a hepatitis virus, and their incidence …”

“…As these two large populations, “first‐time blood donors” and “examinees of hepatitis virus screening”, were used as the basis for the estimation, this type of population was considered to include those who were not aware of their infection. The results showed that the estimated number of HBV latent carriers was 481 470 and that of HCV latent carriers was 295 956 (as of 2011; Table ) . As the opportunity for hepatitis virus screening has increased in Japan since the late 1990s, a dramatic decline was found in a comparison of 2005 estimates, in which the number of HBV latent carriers was 903 145 and HCV latent carriers was 807 903 .…”

“…10 Many large-scale epidemiological or clinicopathological studies have been undertaken to explore the relationship between persistent infection of hepatitis virus and liver diseases, including HCC, the natural course of patients persistently infected with a hepatitis virus, and their incidence. [8][9][10][11][12][13][14]…”

“…4). [11][12][13] Another large-scale survey was undertaken using data from a 5-year project for nationwide HBV and HCV screening, which was launched in April 2002 by the Japanese government. 13 The government provides a health checkup every 5 years to all Japanese residents from the age of 40 years to 70 years.…”