A safety study of children vaccinated against influenza has found no repeat of the significant adverse events that occurred last year, according to a letter to the Medical Journal of Australia.

In 2010, the national influenza vaccination program for children under five years was suspended after high fevers and a significantly higher than expected incidence of convulsions were observed following the administration of trivalent influenza vaccine (TIV).

More than 50 per cent of parents of children who were administered Fluvax or Fluvax Junior reported high fever after vaccination, and the incidence of febrile convulsions was 4.4 per 1,000 doses. Most reports of adverse events were from Western Australia.

In response, WA Health established an online registry for vaccine-associated adverse events and a prospective safety study of the 2011 TIV in children aged under five years has begun.

From 15 March to 29 April 2011, 2,227 doses of TIV - 2130 doses of Vaxigrip and 97 doses of Influvac - were administered to children aged under five years in Western Australia, wrote Associate Professor Christopher Blyth of the University of Western Australia.

Adverse events in four children were reported: two with elevated temperatures; one with vomiting and diarrhoea; and one with fever and convulsions. The child with fever and convulsions had a respiratory tract infection at the time of vaccination, and all four children were administered other vaccines with TIV.

Of the 144 children enrolled in the safety study during the same period, 10 children (seven per cent) had adverse reactions. No convulsions were reported and none of the children required assistance from a medical practitioner.

"These data demonstrate that the significant adverse events that occurred after administration of TIV in 2010 have not been observed in WA during early 2011" Assoc Prof Blyth wrote.

"Ongoing surveillance is underway and will continue. Poor uptake of influenza vaccination in Australian children is likely to result in increased influenza-related hospitalisation, morbidity and mortality.

"Data such as those reported here are required to reassure the community of the safety of this vaccination program before the expected start of the 2011 influenza season."

The Medical Journal of Australia is a publication of the Australian Medical Association.

Source:
Medical Journal of Australia