According to the literature data vaccination with whole-cell vaccines induces protective immunity lasting 6 8 years [ 11, 14], whereas protective immunity induced by vaccination with acellular pertussis vaccine lasts 4 6 years and longer [ 15- 17].
Variables collected in both studies included demographic data, vaccination status, laboratory results, chronic conditions, and pregnancy.
Such characteristics included: average patient attendance data; vaccination coverage rates; and District officers' descriptions of health centre performance.
The demographic data, vaccination coverage, status of HBV infection, and anti-HBs responses in children are shown in Table 1.
The collected information included personal data, vaccination history, clinical symptoms of the current illness, and treatment before hospitalization.
With the inclusion of the new hospital incidence data, vaccination could prevent 4,008 cases of community acquired hospitalizations and 599 cases of nosocomial cases (Table 1) for children under five years of age.
