ABSTRACT
Objective To assess the safety, immunogenicity and efficacy of group A and C meningococcal polysaccharide vaccine (A/C MPV) in response to an outbreak of group C meningococcal disease. Methods A vaccination campaign with A/C MPV was prompted 6 weeks after the use of group A MPV in Laibin city, Guangxi, where an outbreak of group C meningococcal meningitis occurred in 2002.Vaccinees were observed for local and systemic reactions after the vaccination and followed up for the meningococcal disease for 5 years. Blood samples were collected from 71 people in the epidemic and 43 in the non-epidemic areas before and 1 month after the vaccination and examined by ELISA to detect IgG antibodies to group A and C polysaccharides. Results The vaccination coverage was 97%. No significant adverse reactions were observed. The positive rates of group C antibodies after vaccination was between 97.67% and 100% among the populations in the epidemic and non-epidemic areas, as well as among those negative and positive for group C antibodies prior to the vaccination.The geometric mean anti-C concentrations ranged 30.81 μg/ml to 37.44 μg/ml, showing no significant difference between groups. The incidence rate of meningococcal disease in students with timely immunization (218.58/100 000) dropped by 69.02% , when compared to that in those with delayed immunization (705.72/100 000). No clinical cases were identified during the follow-up period of 15 760 person-years. Conclusion The vaccination campaign with the Chinese group A/C MPV seemed successful in controlling the group C meningococcal outbreak.The vaccine was shown to be safe even administered after the group A vaccine only 6 weeks apart. It could induce high levels of antibodies in vulnerable population and significantly increase antibody levels in seropositive individuals, thus providing a protection of at least 5 years.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the safety of a group A + C meningococcal polysaccharide vaccine as part of a phase IV clinical trial.</p><p><b>METHODS</b>The study area was divided into 108 clusters according to the principle of cluster randomization, stratified and paired sampling methods. 54 out of 108 clusters served as observation groups were administered A + C vaccine, while the rest 54 groups were administered Vi polysaccharide vaccine. An adverse event surveillance system was established to monitor the adverse events following the vaccination campaign. Identical form and methods were used for data collection to investigate the adverse events following the vaccination of both A+ C vaccine and Vi vaccine.</p><p><b>RESULTS</b>34,543 people were vaccinated, including 18,167 of whom received A + C vaccine, while the other 16,376 received Vi vaccine. The rates of immediate injection reaction and unsolicited non-serious adverse events from A + C vaccine group were 0.44% and 0.38% while of Vi vaccine group were 0.79% and 0.73% respectively. At the solicited adverse event survey on 3-day-post-vaccination, 1239 vaccinees were followed-up including 771 received A + C vaccine and 468 received Vi vaccine. The local injection reaction rate of A + C vaccine group on the 1st day was significantly higher (X2 = 13.98, P = 0.0002) than that of Vi vaccine group. Neither the local injection reaction rate nor the system reaction rate between both groups was significantly different on 2nd and 3rd day, post vaccination. It was not statistically different when comparing fever onset rate between those who received vaccine and those who did not, in each vaccine group. There were no serious adverse events observed.</p><p><b>CONCLUSION</b>Results showed that the side effects of A + C vaccine and the Vi vaccine were mild and safe for vaccination campaigns targeting on populations at different age.</p>
Subject(s)
Adolescent , Adult , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Young Adult , Age Distribution , Meningococcal Vaccines , Allergy and Immunology , Polysaccharides, Bacterial , Allergy and Immunology , Sex DistributionABSTRACT
<p><b>OBJECTIVE</b>In order to evaluate the safety and immunogenicity of group A + C meningococcal polysaccharide vaccine, a controlled field trial was performed among children at 6-24 months and 5-13 years old in Longsheng county, Guangxi Zhuang Autonomous Region.</p><p><b>METHODS</b>More than 600 children were selected in this trial. 428 children, aged 6-24 month-old and 5-13 year-old were involved in two experimental groups and were inoculated 100 microg of group A + C meningococcal polysaccharide vaccine. 103 children in positive control group were inoculated 50 microg of group A meningococcal polysaccharide vaccine while 94 children in negative control group were inoculated 30 microg of Typhoid Vi polysaccharide vaccine. Both systemic and local reactions were observed in each group at 6 h,24 h,48 h and 72 h after inoculation. Blood samples were collected in all children before and at 1 month after inoculation. Additionally, at least 50 blood samples were taken in each experimental group at 6 and 12 months after inoculation. Serum bactericidal antibody was tested by micro bactericidal test.</p><p><b>RESULTS</b>Both systemic and local reactions were mild in two experimental groups with only 3 children (0.7%) had > or = 37. 6 degrees C fever, 4 children (0.9%) appeared mild areola but all adverse reaction disappeared within 48 hours. In 5-13 year-old experimental group, the rates for four-fold increase of bactericidal antibody were 96.59% and 92.15% to group A and group C meningococcus respectively at 1 month after inoculation, and remained 90.91% and 90.08% at 12 months after inoculation.</p><p><b>CONCLUSION</b>Group A + C meningococal polysaccharide vaccine was safe and having good immunogenicity among Chinese children.</p>