A paper recently presented by Avni Joshi, M.D., of the Mayo Clinic, to the International Conference of the American Thoracic Society has raised doubts about the safety and efficacy of the annual influenza vaccine when given to chronically ill children, especially those with asthma who are routinely advised to be immunized against seasonal flus.
The research was carried out over 8 consecutive flu seasons, which should over ride the problem that some years the manufacturers take a punt on the wrong flu strain to base the annual vaccine on.
Dr Joshi and his team conducted a cohort study of 263 children between the ages of 6 months and 18 years, who were evaluated at the Mayo Clinic and had laboratory confirmed cases of influenza. The scientists noted who had and had not received the flu vaccine, their asthma status and whether they required hospitalisation. Their finding showed:
* the children who had recieved the influenza vaccine were three times more likely to be hospitalised due to complications of influenza
* children with asthma who had been immunised had an even higher rate of hospitalisation
As the study was conducted prior to the detection of H1N1, swine flu cannot be blamed for causing any anomalies in the data.
The Mayo Clinic study comes hot on the heels of a Cochrane reveiw on the effectiveness of the influenza vaccine in preventing flu in healthy children. This peer reviewed meta analysis of 51 eligible studies found that in children under 2 years old, the efficacy of the inactivated influenza vaccine was similar to placebo.
The Cochrane review also raised strong concerns about the lack of safety data for the use of these vaccines in children.