The researchers investigated the population impact of a mass vaccination program for hepatitis B virus (HBV) in Taiwan, 15 years after its implementation.
They reported their findings in the latest issue of the Annals of Internal Medicine.
HBV infection is hyperendemic in Taiwan. Before universal HBV immunization was started in Taiwan in 1984, the carrier rate for hepatitis B surface antigen (HBsAg) was 15% to 20% in the general population.
An analysis of serologic markers of HBV in healthy children and adolescents was conducted in the Chung-Cheng District, Taipei City, Taiwan, in 1999.
A total of 1357 persons younger than 15 years of age, who were born after the implementation of universal HBV vaccination were included. In addition, 559 persons 15 to 20 years of age, who were born before the program began were enrolled in the study.
All participants were tested for serum HBsAg, its antibody (anti-HBs), and hepatitis B core antibody (anti-HBc).
| Annals of Internal Medicine |
During the 15 years since the vaccination program was implemented, the prevalence of HBsAg among persons younger than 15 years of age decreased from 10% in 1984, to 0.7% in 1999.
Among persons 15 to 20 years of age, the 1999 prevalence of HBsAg was 7%.
Hepatitis B core antibody seropositivity, which represents HBV infection, was found in 3% of persons younger than 15 years of age and in 21% of persons 15 to 20 years of age.
In the same age groups, the rate of anti-HBs seropositivity was 76% and 71%, respectively.
Dr Yen-Hsuan Ni, of the National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, said on behalf of fellow authors, "Universal vaccination significantly decreased the HBV carrier rate and infection rate among children and adolescents born since the program began."
"By decreasing the carrier pool, continuation of the national HBV immunization program should prevent HBV infection in the children of Taiwan, and, subsequently, adults as well," it was concluded.