A team from Taiwan, China, evaluated the association between a HBV vaccination program and the incidence of childhood hepatocellular carcinoma (HCC) by gender.
The HBV vaccination was launched in 1984 in Taiwan for neonates of mothers carrying hepatitis B e antigen.
Data collected from Taiwan's National Cancer Registry System and the Taiwan Childhood Hepatoma Study Group, between 1981 and 1996, were analyzed. Children aged 6 to 14 years, who were diagnosed as having HCC (201 boys and 70 girls), were included.
HCC boy-girl incidence ratio:
Before vaccination 4:5
After vaccination 1:9
The team measured the incidence of HCC in boys and girls before and after implementation of the vaccination program.
It was found that the boy-girl incidence ratio decreased steadily from 4:5 in 1981-1984 (before the program's introduction) to 1:9 in 1990-1996 (6-12 years after the vaccination program was launched).
The incidence of HCC in boys born after 1984 was significantly reduced, in comparison with those born before 1978 (relative risk [RR], 0.72). No significant decrease in HCC incidence was observed in girls born in the same periods (RR, 0.77).
The incidence of HCC in boys remained stable with increasing age, while, in girls, an increase of HCC incidence with age was observed. These age and sex effects remained the same regardless of birth before or after the vaccination program.
"Our results suggest that boys may benefit more from HBV vaccination than girls in the prevention of HCC," concluded researcher Dr Mei-Hwei Chang.