| [the prevalence of antibody to hepatitis a virus in different age groups of hokkaido inhabitants (author's transl)]. | serum specimens drawn at random from hokkaido inhabitants were tested for antibody to the hepatitis a virus (anti-hav) by radioimmunoassay. the prevalence in different age groups was as follows, cord blood and newborn infants 44.4%, under one year 0%, 1-9 years 5.3%, 10-19 years 0%, 20-29 years 9.1%, 30-39 years 80%, 40-49 years 90%, and over 50 years 100%. this survey confirmed that antibody against hav could pass through placenta and hav had been very common virus by the 1950's in hokkaido. | 1982 | 6281151 |