Mothers' flu link to schizophrenia


By Carol Nader
August 4, 2004

Women who contract the influenza virus in the early stages of pregnancy are three times more likely to give birth to babies who will develop schizophrenia in adulthood, a study has found.

The finding has renewed calls for pregnant women to be vaccinated against the virus, in line with Federal Government recommendations.

The guidelines suggest that women be vaccinated either before or during pregnancy, and say the benefits of vaccination outweigh perceived risks.

Department of Health spokesman Neil Branch said: "There's no evidence of risk of malformations or other damage to the foetus."

The study, published in the Archives of General Psychiatry, indicates that while the risks of schizophrenia are elevated for women who have the virus during the first half of their pregnancy, there is no discernible increased risk for those who have it in the latter stage of pregnancy.

Researchers have suspected for some time that there might be a link between influenza and schizophrenia, but this study is believed to be the first that actually examines women's blood to support the theory.

The team, led by Alan Brown, associate professor of clinical psychiatry and epidemiology at the New York State Psychiatric Institute and Mailman School of Public Health, collected serum from pregnant women between 1959 and 1966. The serum was frozen and evaluated more than 30 years later.

Influenza antibodies were measured in the serum samples derived from the blood of 64 pregnant women whose offspring later developed schizophrenia and 125 women whose children did not develop the mental disorder. "Our data suggest the possibility that up to 14 per cent of schizophrenia cases would not have occurred if influenza exposure during early to mid-pregnancy had been prevented," the report said.

Schizophrenia affects almost one person in 100.

The deputy director of the World Health Organisation Collaborating Centre for Influenza in Melbourne, Alan Hampson, said vaccinating pregnant women against influenza was "highly desirable".

"I think it's a way of reducing one of the causative factors of schizophrenia," he said.

He said when pregnant women were immunised, antibodies were transferred to the unborn child that would give them a degree of protection during their first months.

"If you have a fever then there is evidence that that affects developing brain tissue," he said.

But some doctors are reluctant to vaccinate pregnant women because they are unsure of potentially adverse effects.

Melbourne University professor of psychiatry Pat McGorry said that while it was of concern to have an infection in a developing brain, more research was needed. He said it was premature to suggest all pregnant women should be vaccinated because "you don't know if that would be harmful".