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To the Editor:

In the recent issue of HEPATOLOGY, Lu et al.1 reported that vaccinees' anti-HBs titer waned gradually following neonatal immunization with plasma-derived hepatitis B vaccine. They suggested determining the vaccinees' anti-HBs status at 10 to 15 years after receiving hepatitis B vaccine and administering one or more booster immunizations for seronegative subjects. Their findings were inconsistent with several recent studies, including one of their previous studies published in 2003, which indicated booster doses were not necessary for adolescents who had received neonatal immunization with plasma-derived hepatitis B vaccine.2–8

In fact, the data shown by Lu et al. do not fully support their proposition. First, they revealed that only one (4%) of the 26 adolescents who had been infected by hepatitis B virus (HBV), i.e., those with anti-HBc, after the age of 18 months became HBsAg-positive. Therefore, in spite of frequent hepatitis B exposure or infection during childhood in this high-risk group, the possibility of becoming a carrier was quite low. Second, their study did not provide any direct evidence to support the hypothesis that adolescents born to HBeAg-positive mothers without a “protective” level of anti-HBs are at high risk to get HBV infection or become HBV carrier. Third, the data from the remaining 113 study subjects seemed not supportive for the conclusion because most of them had unknown maternal HBsAg status and no follow-up tests were performed after the last dose of primary vaccination. Finally, low titer responders to neonatal hepatitis B vaccination usually have a weak response to a booster; therefore, it is hardly expected a booster may have long-termed benefit to this group of vaccinees.

The authors drew the conclusions mainly based on the observation of the declining of anti-HBs during the follow-up period. However, the following points should be considered: (1) protection may be dependent on immune memory; and (2) encouragement of safe sex practice other than vaccination, may probably be a more cost-effective method for the prevention of HBV infection among adolescents.

The necessity of booster vaccination for prevention of hepatitis B has been a debatable issue in the last decade. As the strategy of booster vaccination may cause an immense impact to national medical resources, its cost-benefit must be cautiously evaluated.

References

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  • 1
    Lu CY, Chiang BL, Chi WK, Chang MH, Ni YH, Hsu HM, et al. Waning immunity to plasma-derived hepatitis B vaccine and the need for boosters 15 years after neonatal vaccination. HEPATOLOGY 2004; 40: 1415-1420.
  • 2
    Boxall EH, A Sira J, El-Shuhkri N, Kelly DA. Long-term persistence of immunity to hepatitis B after vaccination during infancy in a country where endemicity is low. J Infect Dis 2004; 190: 1264-1269.
  • 3
    Young BW, Lee SS, Lim WL, Yeoh EK. The long-term efficacy of plasma-derived hepatitis B vaccine in babies born to carrier mothers. J Viral Hepat 2003; 10: 23-1030.
  • 4
    Banatvala JE, Van Damme P. Hepatitis B vaccine — do we need boosters? J Viral Hepat 2003; 10: 1-6.
  • 5
    Lin YC, Chang MH, Ni YH, Hsu HY, Chen DS. Long-term immunogenicity and efficacy of universal hepatitis B virus vaccination in Taiwan. J Infect Dis 2003; 187: 134-138.
  • 6
    Liu HB, Meng ZD, Ma JC, Han CQ, Zhang YL, Xing ZC, et al. A 12-year cohort study on the efficacy of plasma-derived hepatitis B vaccine in rural newborns. World J Gastroenterol 2000; 6: 381-383.
  • 7
    Liao SS, Li RC, Li H, Yang JY, Zeng XJ, Gong J, et al. Long-term efficacy of plasma-derived hepatitis B vaccine: a 15-year follow-up study among Chinese children. Vaccine 1999; 17: 2661-2666.
  • 8
    Lee SD, Lo KJ. Control of hepatitis B virus infection by vaccination: the Taiwan experience. J Chin Med Assoc 1998; 61: 501–;506.

Cho-Yu Chan* † ‡, Shou-Dong Lee* ‡, * National Yang-Ming University School of Medicine, Taipei, Taiwan, † Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan, ‡ Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.