A Phase I Clinical Trial for Safety of A Group A, C Polysaccharide Meningococcal and Type b Haemophilus Influenzal Conjugate Vaccine in Children
Haemophilus influenzae is an important pathogen which can cause primary infection and respiratory viral infection in infants and leaded to secondary infections. The infection of haemophilus is a major cause of morbidity and mortality in infants and children. At present, the developed conjugant Hib vaccine is proved to be safe and effective, 90-99% of children will produce antibody of protection after 3 doses. Because Hib vaccine can prevent meningitis, pneumonia, epiglottis inflammation and other serious infection caused by Hib bacteria, the WHO suggested that Hib vaccine should be included in the infant's normal immune programming. Since the use of meningitis aureus polysaccharide vaccine, incidence of a disease in recent years is declined and maintain to the level of 0.5 per 1/100 thousand. But meningitis aureus polysaccharide vaccine with a relatively poor immune response in the infants under the age of two, and the remaining 60% with a low antibody level and a short duration. According to the present immunization schedule, to reach the median level of antibody levels there are at least 4 doses in need. So it is meaningful to improving vaccine immunogenicity, to provide high levels of long-term protection and to reduce the number of injections. The objective of this study is to evaluate the safety of the group A, C polysaccharide meningococcal and type b haemophilus Influenzal Conjugate vaccine.