All issues > Volume 50(5); 2007

Original Article

Korean J Pediatr. 2007;50(5):449-456. Published online May 15, 2007.

Antibody prsistence after Haemophilus influenzae type b (Hib) primary vaccination and response to boosters in Korean children

Hyunju HJ Lee¹, So Eun SE Park², Soo Young SY Lim³, Kyong Min KM Choi⁴, Hoan Jong HJ Lee⁵, Kyung Hyo KH Kim¹

¹Department of Pediatrics, College of Medicine, Ewha Womans University, Seoul, Korea
²Department of Pediatrics, College of Medicine, Pochon Cha University, Seoul, Korea
³Department of Microbiology, College of Medicine, Ewha Womans University, Seoul, Korea
⁴Department of Pediatrics, College of Medicine, Kwandong University, Seoul, Korea
⁵Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea

Correspondence Kyung Hyo KH Kim ,Email: kaykim@ewha.ac.kr

Abstract

Purpose
: Antibody persistence after primary series of Haemophilus influenzae type b (Hib) vaccine and responses to boosters are seldom studied in Korean children. We performed this study to evaluate the antibody titer in relation to booster immunization of Hib vaccine in Korean children.
Method
: One hundred forty four children aged 12-23 months were enrolled in three university hospitals. The immunogenicity of boosters with Hib vaccine was assessed in children previously primed with Hib vaccine. Antibody persistence was also assessed in children who had received 3 doses of Hib vaccine without a booster. Anti-polyribosylribitol phosphate (PRP) IgG antibody levels and bactericidal titers were determined by enzyme immunoassay and bactericidal assay at the Center for Vaccine Evaluation and Study, Medical Research Institute, Ewha Womans University.
Results
: Prior to a booster in the second year of life, geometric mean antibody concentrations were 2.39 g/mL and the percent of subjects who had a anti-PRP antibody level 1 g/mL was 68.6%. After boosting, antibody concentration was 19.09 g/mL and the percent of subjects who had a anti- PRP antibody level 1 g/mL was 96.5%, which reflects previous immune priming. In subjects who had finished primary immunization only, the bactericidal titer was 3,946 and in subjects who had a booster, it was 11,205. Anti-PRP antibody level was correlated with serum bactericidal titer.
Conclusion
: Many children aged 12-23 month old still had protective antibodies after recommended primary immunization only. A booster dose seemed to induce good anamnestic antibody responses in Korean children.

Keywords :Haemophilus influenzae type b, Antibodies, Immunization, Booster