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ISSUE 6 DECEMBER
New drug

Meningococcal group C conjugate vaccine

Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
 

Meningococcal group C conjugate vaccine

Meningitec (Wyeth)
vials containing 0.5 mL
Approved indication: immunisation
Australian Medicines Handbook Section 20.1

Neisseria meningitidis is a major cause of meningitis and infants are particularly at risk. Babies are not currently immunised against the meningococcus because the available polysaccharide vaccines are not very effective. Conjugating the meningococcal group C oligosaccharide to diphtheria protein increases the immune response.1 Immunogenicity data enabled this conjugate vaccine to be approved in the UK, without a trial of the vaccine's efficacy.

A randomised controlled trial compared a conjugate vaccine with a quadrivalentpolysaccharide vaccine in 127 infants aged 15-23 months. Each child had two injections two months apart, followed by a booster dose of polysaccharide vaccine a year later. After two doses the IgG response in the children who received conjugate vaccine was 10 times greater than the response to the polysaccharide vaccine. Their titres were still twice as high one year later. One month after the booster their titres were 50 times greater than those of the children who had the polysaccharide vaccine.2

Meningococcal group C conjugate vaccine is now part of the routine immunization schedule in the UK. A study of the first nine months of experience with the vaccine estimated the short-term efficacy of a single dose to be 92% for toddlers and 97% for adolescents. Only two of the 32 toddlers who developed meningitis had been immunised.3 There are no efficacy data for infants who receive a course of three injections.3

The injections are given intramuscularly. Meningococcal vaccine can be given at the same time as routine childhood vaccines, but there is limited information about giving it with inactivated polio vaccine or varicella vaccine.

Injection site reactions are common. Some children will develop a fever in excess of 38°C and there may be signs of irritability. Convulsions have been reported.

While the conjugate vaccine appears to be safe and effective in the short term, it will not protect people against other causes of meningitis, for example Neisseria meningitidis group B which is more common in Australia.

 

References

  1. Rappuoli R. Meningococcalpolysaccharide-protein conjugate vaccines. Int J Inf Dis 1997;1:152-7 .
  2. MacDonald NE, Halperin SA, Law BJ, Forrest B, Granoff DM. Induction of immunologic memory by conjugated vs plain meningococcal C polysaccharide vaccine in toddlers. JAMA 1998;280:1685-9 .
  3. Ramsay ME, Andrews N, Kaczmarski EB. Efficacy of meningococcal serogroup C conjugate vaccine in teenagers and toddlers in England. Lancet 2001;357:195-6 .