A prominent Japanese researcher reporting on the bird flu drug Tamiflu says the drug may not be safe for children.
Tamiflu (oseltamivir phosphate), is manufactured by drug company Roche - it is an oral anti-viral drug for the treatment of uncomplicated influenza and has been stockpiled by governments around the world as a first line of defence should a bird flu epidemic occur.
It has been approved by the Food and Drug Administration in the U.S. in patients one year and older and adults whose flu symptoms have not lasted more than two days, to treat Type A and B influenza.
Professor Yoshio Hirota from Osaka City University, has just released the final report of a Health, Labor and Welfare Ministry research team which studied the cases of about 10,000 children under 18 who had been diagnosed with influenza since 2006.
The team say flu patients aged between 10 and 17 who took Tamiflu were 54% more likely to exhibit serious abnormal behaviour than those who did not take the antiflu drug and they say Tamiflu appears to increase abnormal psychological behaviour in this group.
The report which will now go to a safety research committee for the Pharmaceutical Affairs and Food Sanitation Council, says the link with Tamiflu cannot be ruled out and calls for more research which focuses on serious abnormal behaviours.
Japanese health officials suspended the use of the drug by 10 to 19 year olds in 2007 after a number of children behaved abnormally after taking it, including one child who started to hop and another who tried to jump from a balcony and the new findings mean a lifting of the ban is unlikely.
Previous research was unable to establish a definitive link between the drug and abnormal behaviour and the main focus of this latest research was the issue of when to lift the ban.
The team's analysis when limited to children who had displayed serious abnormal behaviour that led to injury or death, revealed that those who had taken Tamiflu were 25% more likely to behave unusually and that figure reached 54% among children aged 10 to 17.
However, when taking into account all degrees of abnormal behaviour, including minor behavioural problems such as incoherent speech, the team found that children who took the drug were 38% less likely to behave strangely.