Comparison of hepatitis B vaccine coverage and effectiveness among urban and rural Mongolian 2-year-olds.
BACKGROUND
The prevalence of hepatitis B (HBV) carriage in Mongolia is reported to be 14%. Universal HBV immunization of newborns has been shown to decrease carriage in Asian populations. Mongolia began universal newborn vaccination in 1991. This evaluation of vaccine coverage and effectiveness compares the success of the program between urban and nomadic rural populations.


METHODS
Using random cluster sampling, 148 Mongolian 2-year-olds from seminomadic rural families were compared with 127 2-year-olds from Ulaanbaatar, the capital city.


RESULTS
More than 95% of all subjects received hepatitis B vaccine although rural subjects were less likely to complete the series than were urban subjects. Adequate vaccine response differed significantly: 94.2% of urban subjects versus only 70.2% of rural subjects had protective anti-HBs levels (P < 0.001). Overall the proportion of hepatitis B infection in both samples was lower than the historical Mongolian prevalence. However, unexpectedly 40% of subjects in rural Bayanhongor Aimag (Province) were found to be HBsAg positive.


CONCLUSIONS
The Mongolian infant vaccination program for hepatitis B is successfully reducing the rate of chronic carriage in the immunized generation. However, vaccine response among rural subjects is less than that among urban. There appears to be a pocket of high disease prevalence in Bayanhongor that requires further study.
Edstam
James S
JS
School of Public Health and Community Medicine, University of Washington, Box 357660, Seattle, WA 98195, USA. jedstam@u.washington.edu
Dulmaa
Nyamkhuu
N
Nymadawa
Pagbajabyn
P
Rinchin
Arslan
A
Khulan
J
J
Kimball
Ann Marie
AM
D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007224:Infant Care; D008986:Mongolia / Q000453:epidemiology; D015995:Prevalence; D015397:Program Evaluation; D011897:Random Allocation; D012423:Rural Health; D014504:Urban Health
D017325:Hepatitis B Vaccines