Childhood immunisations

Editor, Dr McIntyre provides an informative guide to childhood immunisations in his recent article 'Update on childhood immunisations' (Aust Prescr 1994;17:91-5) and helpfully provides a more restricted guide to contraindications. He lists contraindications as a concurrent moderate to severe illness, previous anaphylactic reaction to the vaccine (or severe reaction to a vaccine constituent), attenuated live vaccines in immuno compromised patients, and neurological handicap as regards pertussis.

Previously, a fever over 39.5^oC, induration and redness around most of the arm and prolonged inconsolable screaming after pertussis vaccine have been considered a contraindication to repeating it.

Are these still considered contraindications (or were such reactions included as an anaphylactic reaction) and what is the risk of subsequent vaccination in a child who has had such a reaction previously?

Brendon Smith
General Practitioner
Surry Hills, N.S.W.

Dr P. McIntyre, the author of the article, comments:

Dr Smith has raised some important points of clarification regarding contraindications to pertussis immunisations which were not addressed in the original article due to reasons of space. The list of contraindications to active immunisation was intended to apply generally to children presenting for immunisation. With regard to pertussis vaccine specifically, contraindications may be divided into absolute and relative contraindications. Both the new edition of immunisation procedures¹ and the report of the Committee on Infectious Diseases of the American College of Paediatrics² define absolute contraindications to further pertussis vaccine as an immediate severe allergic or anaphylactic reaction or encephalopathy within 7 days. Other reactions such as protracted, inconsolable crying and severe local reactions are considered to be relative contraindications which may preclude further doses, depending upon the clinical status of the patient and their risk both of acquiring pertussis and of having significant complications should this occur. The level of fever considered significant is now generally quoted as more than 40.5^oC rather than 39.5^oC.³ Unfortunately, there are no available data to evaluate the risk of a subsequent adverse reaction following the occurrence of one such reaction. Anecdotal experience certainly indicates that the occurrence of one of these reactions by no means indicates that it will invariably occur if the vaccine is administered again. Very severe local reactions, high fever and inconsolable crying for more than 3 hours would each be expected to affect less than 1% of DTP recipients.⁴ Thus, if contraindications to further pertussis vaccine are limited to the absolute and relative contraindications, there should be very few children receiving CDT rather than DTP, certainly many less than appear to be receiving it currently. These issues have been summarised in a recent statement of the Australian College of Paediatrics.⁴