Antibody to hepatitis A virus in plasma of Danish blood donors and in immune serum globulin produced in Denmark.

Antibody to hepatitis A virus (anti-HAV) was studied in 225 Danish blood donors. The prevalence was found to be 3% in individuals younger than 30 years but then rising with age to 78% in individuals older than 55 years. The titer of anti-HAV in 51 lots of Danish immune serum globulin (ISG) produced from June 1969 to June 1977 was found to vary between 2300 and 5900 except for 2 with titers of 14000 and 28000. The titers did not change during the period and compared well to 3 lots of ISG produced in the USA and selected by the manufacturer because of a high anti-HAV titer.