Pneumococcal 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.

Prevenar (Wyeth)
0.5 mL single dose vials
Approved indication: immunisation
Australian Medicines Handbook Section 20.1

The currently available pneumococcal vaccine contains a mixture of polysaccharides from the 23 most prevalent serotypes of pneumococcus. Although the vaccine is recommended for people at high risk of pneumococcal disease, it is not very immunogenic in infants and is not recommended for children under two year sold. The new vaccine only contains polysaccharides from seven serotypes, but it is conjugated to a diphtheria protein. This provokes an immune response in infants, so the vaccine can be used to immunise children between six weeks and nine years of age.

If immunisation begins at six to eight weeks of age the infant needs three intramuscular injections at least four weeks apart, followed by a booster injection before the age of two. Children who are one to two years old need two injections, but children over two years old need only a single dose.

Although older children require only one injection they are more likely to react to it. Soreness at the injection site occurs in nearly 60% of cases and in 20% this interferes with limb movement. Fever, irritability and vomiting are other very common adverse effects. Reactions are more likely if the child is being simultaneously immunised with pertussis vaccine.

Although 51-90% of children will develop an antibody concentration of 1.0microgram/mL after three doses, the minimum protective concentration is unknown. A large trial in the USA found the efficacy of the vaccine was 87% against pneumonia caused by pneumococci from the same serotypes as used in the vaccine. There was also a 9% reduction in visits to the doctor for otitis media.1

The American Academy of Pediatrics has recommended that all children, 23 months and younger, be given the vaccine with their routine immunisations.2 Australia is more likely to opt for protecting high-risk groups rather than universal immunisation. The Australian Standard Vaccination Schedule already requires multiple immunisations. In addition to the extra injections it is not clear how the new vaccine will interact with some of the combined vaccines used in Australia. While the vaccine may help to reduce the significant morbidity of pneumococcal disease in Aboriginal children, there is little information about its use in indigenous peoples. The pneumococcal serotypes used in the vaccine may differ from those which cause disease in central Australia.