Health authorities continue to put seasonal flu vaccine on hold for young children

A week long national evaluation of cases of fever with convulsions in young children following a seasonal flu vaccination has so far found no pattern of increased incidence of this side effect, other than higher numbers in WA.

While much has been done to understand this, we require additional time to complete our investigations. Given the ongoing and incomplete scientific and clinical case review, the moratorium on the use of seasonal influenza vaccine in children 5 years and less will continue.

This advice to immunisation providers and parents was originally given a week ago following preliminary information received by WA Health authorities that children 5 years and younger were experiencing fever with convulsions in higher than expected numbers in WA following seasonal influenza vaccination. Action was taken immediately to temporarily suspend seasonal influenza vaccination in children 5 years and younger while, at the same time, encouraging continued flu shots for the rest of the population.

During the week the Commonwealth Department of Health and Ageing has arranged for:

• batch testing of the vaccine by the TGA and other independent experts, which has so far shown that the vaccine is satisfactory. The manufacturer has also tested the vaccine which has shown no abnormalities. TGA has commissioned additional ongoing research to document the tendency of the 2010 seasonal flu vaccine to produce fevers compared to the seasonal influenza vaccines in previous years.
• state and territory health authorities to complete their reporting of adverse events to the TGA which is continuing
• teams from the TGA and Australian Technical Advisory Group on Immunisation to work with Health Authorities in WA
• vaccination providers, and parents to be alerted to this preliminary information as a precautionary measure.
  Sophisticated laboratory testing and reviews of clinical cases are continuing but will take more time to complete.

The evaluation has found so far that children reported as having fever with convulsions following seasonal flu vaccination have recovered without long term effects except one complex case who needed ICU in WA and is not yet recovered. A further case in Queensland is being investigated as an unexplained death.

So far, our review has confirmed that the number of cases of fever with convulsions in children 5 years or less after seasonal flu vaccination reported to the TGA are a total of 77 cases. Most of these are from WA.

The national breakdown of fever with convulsions reported by health authorities to the TGA so far are: WA 57, NSW 4, Vic 6 , Queensland 4, SA 2 , Tasmania 1, ACT 1 and two under review.

Influenza vaccine is designed to stimulate the immune system to prepare it to fight influenza virus infection. In a percentage of people (around 20%) it causes fever as part of that stimulation which can be more marked in young children. These fevers normally quickly subside. Fever from any causes may uncommonly result in convulsions in toddlers and these presentations are seen regularly in our EDs, especially in the winter season after infection. They are usually shortlived with full recovery. After vaccination the usual rate of fever with convulsions has been one tenth of one percent to one hundredth of one percent (0.1% to 0.01%) .

Any child who has had the seasonal flu vaccination in recent weeks whether they experienced short term fever or not can be assured they are safe. However, if parents have any concerns, they should consult their GP.

With the onset of the flu season only a few weeks away we continue to recommend seasonal flu vaccination for those who are vulnerable to poor outcomes with the flu including those with underlying medical conditions especially respiratory or cardiac disease, those people over 65 years, pregnant women, and our Indigenous population.

Judging by this year’s North American experience during winter where pandemic H1N1 2009 influenza has been the predominant flu strain, especially for younger people under 65 years, we predict that swine flu will be the predominant flu in our winter this year. Free swine flu vaccine is available as a choice for parents and is available for all people 6 months and over.

Intensive research by the TGA, the Australian Technical Advisory Group on Immunisation and other expert groups is ongoing.

(Source: Australian Government Department of Health and Ageing: May 2010)