NeisVac-C™: Clinical Update (vaccination against meningococcal meningitis)
Serogroup C meningococcal disease is an important cause of invasive bacterial infections in children and young adults and is associated with significant morbidity and mortality. Conjugate vaccines have proven to be safe and effective in clinical practise and confer the advantage of long-term polysaccharide-specific immunity for even the youngest at-risk population.
The new meningococcal C conjugate vaccine, NeisVac-C™ (Baxter), containing de-O-acetylated serogroup C meningococcal polysaccharide conjugated to tetanus toxoid carrier protein, offers an alternative to the currently available purified polysaccharide vaccines. The vaccine has been extensively evaluated in a total of six completed clinical studies in children/adolescents of all ages and adults. Among the more than 2.700 volunteers who received the vaccine in clinical studies to date, NeisVac-C™ was found to be well tolerated and highly immunogenic, eliciting both specific and boostable immune responses.
Among infants aged two to four months, serum bactericidal antibody (SBA) titers of 32 were achieved in 99% of the vaccinees after two doses (GMT: 773; 95% CI: 609-982): and in 100% after three doses (GMT: 1062; 95% CI: 856-1319), with a booster dose in the second year of life inducing an anamnestic response. One administration of vaccine in toddlers aged 12 to 17 months resulted in an SBA GMT of 564 (95% CI: 406-783) for NeisVac-C™, 123 (95% CI: 78-195) for MCC-CRM197 (Wyeth) and 141 (95%CI: 90-222) for MCC-CRM197 (Chiron). Also, a single dose of NeisVac-C™ was demonstrated to induce immunologic memory in these toddlers. One administration of NeisVac-C™ resulted in SBA GMT’s of 32 in >98% of preschoolers aged 3.5 to 6 years, 100% of school leavers aged 13 to 17 years and 100% of adults. Furthermore based on an interim analysis from an infant study (n=600) in the UK, the two dose regimen is as immunogenic as the three dose regimen in this age group.
Following licensure, NeisVac-C™ demonstrated excellent efficacy and tolerability within the scope of a large-scale UK-vaccination program (1.8 million children and adolescents. Systemic events were very rare (<0.01%), local reactions were consistent with established vaccination experience.
As of April 2002, NeisVac-C™ is licensed for vaccination in infants from 2 months of age (3 dose regimen), and in children, adolescents and adults (single dose regimen) in 16 European countries, as well as in Canada and Argentina.