Estimating numbers of persons with persistent hepatitis B virus infection transmitted vertically and horizontally in the birth cohort during 1950–1985 in Japan

Abstract

Vertical HBV infection had stayed constant until immunoprophylaxis of mother-to-baby transmission was implemented in 1986 in Japan. In contrast, horizontal HBV infection decreased over years. The decrease would be due to many factors, including improved socioeconomic environments, advanced medical maneuvers and equipment, and careful vaccination procedures.

High prevalences of hepatitis B and C virus infections among adults living in Binh Thuan province, Vietnam

“…We could not identify the transmission mode by using only genotyping results because all HBV DNA positive subjects in our family‐tree surveys were infected with HBV genotype B. A recent study among HBV carriers in the birth cohort during 1950–1985 in Japan estimated that horizontal transmission was approximately sesquialterally as frequent as vertical transmission . Therefore, it is possible that for the first time our family‐tree survey has supposed that not only perinatal vertical transmission or intrafamilial horizontal spread but also horizontal infection of HBV from an extrafamilial source such as babysitter or kindergarten classmate in early childhood are important in Vietnam.…”

“…A recent study among HBV carriers in the birth cohort during 1950-1985 in Japan estimated that horizontal transmission was approximately sesquialterally as frequent as vertical transmission. 20 Therefore, it is possible that for the first time our family-tree survey has supposed that not only perinatal vertical transmission or intrafamilial horizontal spread but also horizontal infection of HBV from an extrafamilial source such as babysitter or kindergarten classmate in early childhood are important in Vietnam. Hence, preventive strategies for horizontal HBV transmission should be properly considered, along with the universal HBV vaccination for infants.…”

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia

“…Our result is similar to those in previous studies. In Japan, where genotype C is predominant as in Cambodia, a study among HBV carriers in the birth cohort during 1950–1985 estimated that horizontal transmission was approximately sesquialterally as frequent as vertical transmission …”

Reduced prevalence of hepatitis B surface antigen positivity among pregnant women born after the national implementation of immunoprophylaxis for babies born to hepatitis B virus‐carrier mothers in Japan

“…According to estimations of the number of HBV carriers and the frequencies of horizontal and perinatal HBV transmission from 1950 to 1985 in Japan, as reported by Sato et al, 9 the number of HBV carriers has decreased since the 1950s; furthermore, the estimated frequencies These findings indicate that the 1986 implementation of a selective vaccination program in Japan might have effectively reduced the population of HBV carriers infected through perinatal transmission. We note that the number and frequency of HBV carriers infected through horizontal transmission decreased from 1950 to 1985 due to improvements in hygiene and medical settings.…”

“…According to estimations of the number of HBV carriers and the frequencies of horizontal and perinatal HBV transmission from 1950 to 1985 in Japan, as reported by Sato et al ., the number of HBV carriers has decreased since the 1950s; furthermore, the estimated frequencies of HBV carriers consequent to perinatal transmission were 20–32% among individuals born between 1950 and 1959 and 73–94% among those born between 1980 and 1985. These findings indicate that the 1986 implementation of a selective vaccination program in Japan might have effectively reduced the population of HBV carriers infected through perinatal transmission.…”