Kawerau revisited: hepatitis A and B seroprevalence in 1984 and 1993.
OBJECTIVE
To determine if protection against hepatitis B is maintained in a cohort of children nine years after primary vaccination; To compare the prevalence of hepatitis B infection in 1984, before the introduction of hepatitis B vaccine, with that in 1993; To compare the prevalence of hepatitis A antibody (anti-HAV) in children in 1984 and 1993.


METHODS
Serum samples collected from children attending Kawerau Intermediate School in 1993 were tested for hepatitis B markers and anti-HAV, and the results were compared with those in children attending the same school in 1984.


RESULTS
Antibody to hepatitis B surface antigen (anti-HBs) was detected in 91.8% of children documented to have received hepatitis B vaccine in 1984. Seroconversion for antibody to hepatitis B core antigen (anti-HBc) had occurred in 5%. None had suffered a clinical illness. No vaccinee had a positive test for hepatitis B surface antigen (HBsAg). The prevalence of hepatitis B infection had fallen from 71.7% in 1984 to 24.2% in 1993. The prevalence of hepatitis A was 29.6% in 1984 and 0.4% in 1993.


CONCLUSIONS
Protection against clinical disease and chronic hepatitis B infection is maintained nine years after primary vaccination. Hepatitis A has virtually disappeared among children in Kawerau.
Lucas
C R
CR
Hepatitis Foundation, Whakatane.
Milne
A
A
Hopkirk
N
N
D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006506:Hepatitis A / Q000453:epidemiology* / Q000276:immunology; D006508:Hepatitis Antibodies / Q000097:blood; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000276:immunology* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence
D006508:Hepatitis Antibodies; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines