Evaluation of Antibodies Against Haemophilus influenzae Type b in Korean Adults.
10.14776/piv.2017.24.3.125
- Author:
Ji Hyen LEE
1
;
Han Wool KIM
;
Soyoung LEE
;
Kyung Hyo KIM
Author Information
1. Department of Pediatrics, Medical Research Institute, Ewha Womans University School of Medicine, Seoul, the Republic of Korea. kaykim@ewha.ac.kr
- Publication Type:Original Article
- Keywords:
Haemophilus influenzae type b;
Antibodies;
Adult;
Aged
- MeSH:
Adult*;
Aged;
Antibodies*;
Child;
Disease Susceptibility;
Enzyme-Linked Immunosorbent Assay;
Haemophilus influenzae type b*;
Haemophilus influenzae*;
Haemophilus*;
Humans;
Immunization;
Immunization Programs;
Immunoglobulin G;
Korea;
Young Adult
- From:Pediatric Infection & Vaccine
2017;24(3):125-133
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: After the introduction of Haemophilus influenzae type b (Hib) vaccine in 1995 in Korea, it was included in the national immunization program in 2013. In the post-Hib vaccine era, some studies in other countries reported that invasive Hib disease affects adults, especially the elderly and immunocompromised persons, more often than it affects children. To evaluate disease susceptibility, quantitative and qualitative analysis of anti-polyribosylribitol phosphate (PRP) antibodies were carried out in Korean adults aged 20 to 85 years. METHODS: Sera were collected from 39 healthy adults (20 to 50 years of age) and from 30 elderly adults (75 to 85 years of age) who did not have immune-compromising conditions. The concentration of anti-PRP immunoglobulin G (IgG) and serum bactericidal indices (SBIs) were measured by enzyme-linked immunosorbent assay and serum bactericidal assay. RESULTS: Geometric mean concentrations of anti-PRP IgG and geometric mean SBIs were 0.88 µg/mL (95% confidence interval [CI], 0.17 to 3.85) and 354 (95% CI, 50 to 2,499) in young adults and 1.67 µg/mL (95% CI, 0.53 to 5.24) and 449 (95% CI, 146 to 1,376) in elderly adults, respectively. When the threshold of seropositivity for anti-PRP IgG was applied as 0.15 or 1.0 µg/mL, which is the protective antibody level in children, seropositive rates were 87.2% or 53.8% in young adults and 100% or 60% in elderly adults. The seropositivity rates of the SBI (SBI ≥4) were 82.1% and 100% in the groups, respectively. CONCLUSIONS: Most subjects in the adult and elderly adult groups display immunity to Hib based on quantitative and qualitative antibody levels, but not all. Because high immunization and low Hib circulation rates may reduce the natural Hib immunity in the population, monitoring Hib immunity as well as disease are needed continuously.
