Although all nationwide countries provide a booster dose from the Hib vaccine, some nationwide countries recommend 2 doses being a principal series, whereas various other countries recommend 3 doses before a year of age. The aim of this study was to judge the immunogenicity of the primary group of Hib conjugate vaccines in Korean infants through a meta-analysis. 2 dosages and 3 dosages, 80.6% (95% confidence period [CI]; 76.0-85.1%) and 95.7% (95% CI; 94.0-98.0%) of newborns achieved an antibody level 1.0 g/mL, respectively. The immunogenic response towards the PRP-T vaccine was appropriate after an initial WAY-100635 maleate salt group of 3 dosages and in addition 2 dosages. A reduced variety of dosages being a principal series could possibly be properly regarded in Korean newborns. Keywords: type b, Vaccines, Immunity, Meta-analysis Launch type b (Hib) was a significant reason behind bacterial meningitis and various other serious invasive illnesses among children aged <5 yr before the introduction of the Hib conjugate vaccines (1). A dramatic decrease in Hib disease burden was noted in countries that launched the Hib conjugate vaccine into program immunization schedules (2). Four basic different types of conjugate vaccines have been licensed for use in infants against Hib diseases. These vaccines differ in the carrier proteins, structure and length of the capsular polysaccharide molecule, polyribosylribitol phosphate (PRP) and the method of conjugating the carrier protein to the polysaccharide. The first conjugate produced was the diphtheria toxoid conjugate (PRP-D), followed by mutant diphtheria toxin conjugate (PRP-CRM), meningococcal outer membrane protein conjugate (PRP-OMP) and tetanus toxoid conjugate (PRP-T). Hib conjugate vaccines have been shown to be highly efficacious against invasive Hib disease and safe in clinical trials (3-5). Vaccine efficacy of Mlst8 Hib vaccines are assessed in correlation with the level of production of specific anti-PRP IgG (6). An anti-PRP level 1.0 g/mL is considered predictive for long-term protection from invasive disease in a vaccinated populace (7). Based on this, the WHO recommendations on evaluating the efficacy of Hib conjugate vaccines have been released, e.g. effective vaccines induce 1.0 g/mL of anti-PRP antibody in 70% or more of infants 1 month after completion of the primary immunization series (8). With the known security and proven effectiveness of the Hib conjugate vaccines, WHO recommends it to be WAY-100635 maleate salt included in all routine infant immunization programs, regardless lack of local surveillance data (9). By the end of the year 2005, Hib vaccines were included in the program infant immunization program in 101 out of 192 WHO member countries (10). However, it is not yet introduced into the national immunization program in Korea. To make important decisions around the policy for Hib vaccination, a nationwide study around the epidemiologic status in relation to the disease burden of invasive Hib diseases as well as cost-effectiveness study is urgent. Also, the appropriate routine should be decided. The Hib vaccination routine differs between countries in quantity of doses and periods of vaccination. At present, the current recommendations for the vaccination routine for Hib vaccine in Korea is usually that the primary series be given at 2, 4 and 6 months of age for the PRP-T and PRP-CRM vaccine and at 2 and 4 months of age for the PRP-OMP vaccine, with a following booster dose at 12-15 months of age for all those three types of vaccines. Although all countries give a booster dose of the Hib vaccine, some countries recommend 2 doses as a main series, whereas other countries recommend 3 doses before 12 months of age. The objective of this study was to evaluate the immunogenicity of a main series of Hib conjugate vaccines in Korean infants through a meta-analysis. We will therefore determine whether the immunologic responses are acceptable after 3 doses (given at 2, 4, and 6 months of age) and also after 2 doses (given at 2 and 4 months of age) of the Hib conjugate vaccine. MATERIALS AND METHODS Literature search MEDLINE, KoreaMed, and the Korean Medical Database were searched for all studies of Hib conjugate vaccine in Korean children. The search included terms in the title or key words, applying the terms ‘type b’, ‘Hib’, ‘vaccination OR vaccine’ and ‘immunogenicity’. Also, a manual search of studies was carried out on studies referenced in publications identified through the initial search and experts on Hib vaccine in Korea were contacted for unpublished data or ongoing studies. Selection criteria We included all clinical trials that reported immunogenicity WAY-100635 maleate salt results following a main series (immunization at 2, 4, and 6 months of age) of Hib conjugate vaccine in healthy Korean infants. The primary end result measure.
