Response to primary and booster vaccination with 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine in Korean infants.

BACKGROUND: This randomized single-blind study in Korea evaluated noninferiority of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) versus the 7-valent pneumococcal conjugate vaccine (7vCRM) when both were coadministered with H. influenzae type b (Hib) conjugate vaccine, as opposed to coadministration with diphtheria-tetanus-acellular pertussis-based combination vaccines in previous studies. METHODS: Infants received 3 primary doses at 2, 4, and 6 months and a booster dose at 12 to 18 months of PHiD-CV (N = 374) or 7vCRM (N = 129), both coadministered with Hib vaccine. Immune responses were measured 1 month postdose 3 and postbooster using 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. RESULTS: PHiD-CV-induced antibody responses against each of the vaccine pneumococcal serotypes and protein D. Noninferiority to 7vCRM was demonstrated for all 10 PHiD-CV serotypes in terms of percentages of subjects reaching an antibody concentration ≥0.2 µg/mL after primary vaccination. Postprimary and postbooster, percentages of subjects with antibody concentration ≥0.2 µg/mL or opsonophagocytic activity titer ≥8 were generally consistent between groups for each pneumococcal serotype common to both vaccines. The safety and reactogenicity profiles of PHiD-CV and 7vCRM were generally comparable after both primary and booster vaccination. CONCLUSIONS: In this Korean study, 3-dose PHiD-CV priming followed by a booster dose was immunogenic for all 10 vaccine pneumococcal serotypes and protein D. Noninferiority to 7vCRM in terms of enzyme-linked immunosorbent assay threshold responses postpriming was demonstrated. The safety and reactogenicity profiles of both vaccines when coadministered with Hib vaccine were generally comparable.

Nasopharyngeal pneumococcal carriage of children attending day care centers in Korea: comparison between children immunized with 7-valent pneumococcal conjugate vaccine and non-immunized.

To confirm the effect of 7-valent pneumococcal conjugate vaccine (PCV7), pneumococcal nasopharyngeal (NP) carriage was compared between vaccinated (3 + 1 doses PCV7) and non-vaccinated children. Vaccinated subjects were recruited from highly vaccinated regions (≥ 60%), Seoul and Incheon whereas control subjects were recruited from Jeju Island where vaccination rates are low (< 15%). NP swabs were obtained from 400 children aged 18-59 months. Serotype and antibiotic susceptibility was analyzed. Pneumococcal carriage rate was 18.0% (36/200) and 31.5% (63/200) for the vaccinated and control group, respectively. Among those vaccinated, 41.7% (15/36) of the serotypes were vaccine-related type (VRT: 6A, 6C, 19A) with the most common serotype 6C. The next common type was non-typable/non-capsule 30.6% (11/36) followed by non-vaccine type 16.7% (6/36) and vaccine type (VT) serotypes were found in only 11.1% (4/36). In contrast, 52.4% (33/63) of the isolates in the control group were VT. Resistance rates for penicillin and erythromycin were lower in the vaccine group (vaccine vs control; penicillin 45.2% vs 71.4%, erythromycin 74.2% vs 90.5%, P < 0.05). Multi-drug resistance was also lower in vaccinated subjects (vaccine vs control; 45.2% vs 69.8%, P < 0.05). PCV7 reduces carriage in VT which leads to replacement of pneumococci by antibiotic susceptible VRT or non-vaccine type strains.

Update on pertussis and pertussis immunization.

Pertussis is a highly contagious respiratory tract disease caused by Bordetella pertussis infection. The clinical manifestation of this infection can be severe enough to cause death. Although pertussis has been supposed to be a vaccine-preventable disease ever since the widespread vaccination of children against pertussis was started, since the 1990s, cases of pertussis and related fatalities are on the rise, especially in countries with high vaccination coverage. In Korea, there have been no deaths due to pertussis since 1990, and the vaccination rate continues to be approximately 94%. However, the number of pertussis cases reported to the Korea Center for Disease Control and Prevention has tended to increase in the 2000s, and in 2009, there was an obvious increase in the number of pertussis cases reported. This review aims to present the latest information about the pathogenesis, diagnosis, treatment, and prevention of pertussis.

High prevalence of extended-spectrum beta-lactamase-producing strains among blood isolates of Enterobacter spp. collected in a tertiary hospital during an 8-year period and their antimicrobial susceptibility patterns.

Of 72 blood isolates of Enterobacter spp. collected over an 8-year period, 50% (36 of 72) were derepressed or partially derepressed AmpC mutants. The extended-spectrum beta-lactamase (ESBL) production rate was 43% (31 of 72 isolates), and 67.3% (31 of 46) of extended-spectrum cephalosporin-resistant strains produced ESBLs. Thus, a confirmatory test for ESBL production is necessary for extended-spectrum cephalosporin-resistant Enterobacter spp.

Genome type analysis of adenovirus types 3 and 7 isolated during successive outbreaks of lower respiratory tract infections in children.

Adenovirus is an important cause of respiratory infections in infants and children. Fifty-one serotypes have been identified, and adenovirus type 3 (Ad3) and Ad7 have often been associated with outbreaks of severe respiratory tract infections. Each serotype can be further divided into genome types based on the patterns of digestion of their DNAs with restriction enzymes. DNA restriction analysis was performed with 56 strains of Ad3 and 98 strains of Ad7 by using 12 restriction enzymes recognizing 6 bp (BamHI, BclI, BglI, BglII, BstEII, EcoRI, HindIII, HpaI, SalI, SmaI, XbaI, and XhoI). The virus strains were isolated during outbreaks of lower respiratory tract infections in children during an 11-year period from 1990 to 2000 in Seoul, Korea. Among the Ad3 strains, seven genome types were identified; Ad3a and six novel types (Ad3a13, Ad3a14, Ad3a15, Ad3a16, Ad3a17, and Ad3a18). Multiple genome types cocirculated during outbreaks, and some of these were isolated during the 11-year observation period, while others were restricted to particular outbreaks. For Ad7, two genome types, Ad7d and Ad7l, the latter of which is a novel genome type, were identified. A shift in genome types occurred from Ad7d to Ad7l during successive outbreaks. Mortality was 3.6% among children with Ad3 infections and 18% among children infected with either of the Ad7 genome types. In conclusion, the data confirm that Ad3 genome types are more diverse than those of Ad7 and suggest that shifts of genome types may occur during successive outbreaks of Ad3 and Ad7.