Reactogenicity of Meningococcal C Conjugate Vaccines When Administered at the Same Time as, or a Month Prior to or After, Tetanus and Diphtheria Booster Vaccinations

Abstract

Introduction: This single blind study was conducted to address safety concerns regarding co-administration of diphtheria/ tetanus (DT,Td) boosters and meningococcal C conjugate (MCC) vaccines containing diphtheria or tetanus conjugate proteins.

Methods: 1754 subjects (835 preschoolers and 919 school leavers) were randomised to receive one of three MCC products a month before, after or at the same as routine DT or Td boosters. They (or their parents) completed a health diary for 10 days to record local reactions and systemic symptoms after each vaccination. The effect of antibody levels pre- and post-vaccination, pre-existing allergies and medication taken before and for up to ten days after vaccination on reactogenicity was assessed.

Results: No relationship between pre-vaccination antibody levels and local reactions or systemic symptoms was found. Local reactions were more common after DT/Td than MCC vaccination and were related to post-vaccination diphtheria and tetanus antibody levels in younger children and to the post-vaccination tetanus only antibody levels in older children. Pre-existing allergies were not related to reactogenicity. Use of analgesics/ antipyretic medication significantly reduced the incidence of local reactions and of some systemic symptoms. In the first three days after vaccination there was an excess of some systemic symptoms including fatigue/ malaise and headache for all ages, and crying/ irritability for younger children and nausea/ vomiting and dizziness/ faintness for older subjects. Eleven serious adverse events were reported, none of which was deemed related to vaccination.

Conclusion: MCC vaccines can be given under the above schedules and safely in the presence of raised diphtheria and tetanus antibody levels without materially altering reactogenicity profiles of either vaccine.