Canadian Tamiflu warnings

Health Canada is following the US FDA in warning of adverse neurobehavioral effects of the influenza antiviral, Tamiflu. The drug is prescribed much more often in Japan, where it is used in seasonal flu, than in the US. The effects have been reported mainly in children and have included some suicides. It isn't known whether the drug was responsible for these deaths and if so, how. The US FDA has not made any determinations but issued the warning as a precautionary measure.

The Vancouver Sun ran the story under the headline, "Bird flu vaccine leaves 10 Canadians dead." (hat tip, ColdClimatePrepper on the Flu Wiki Forum). One wonders what it will take to get headline writers to understand there is a vital difference between an antiviral drug and a vaccine? This is not a harmless error. It could easily discourage some people from getting a flu shot which in turn could lead to their deaths. Reporters don't write their headlines but they should give vigorous feedback when something like this happens. In other respects the Vancouver Sun article is interesting and informative:

Ten Canadians have died and at least 74 had adverse reactions after taking Tamiflu, but Health Canada didn't issue a public update about the flu drug until Wednesday.

The update came more than two weeks after international warnings were posted of adverse reactions to the medication among children and youth.

Wednesday's Health Canada information update said people in other countries -- particularly children and teens in Japan -- exhibited strange behaviour, including hallucinations and self-injury, after taking the drug.

Among those exhibiting this behaviour, there have been 25 reported deaths around the world in the most recent one-year period.

Health Canada said it has "not received any such reports" of abnormal behaviour among young people in Canada. (Carly Weeks, Vancouver Sun)

The Health Canada bulletin reports 84 adverse reactions among Canadians since February 2000, with 10 deaths. Seven adults were reported to have had "psychiatric adverse events." The Japanese reports were mainly children but in the Canadian cases only two were under age 20. This year there have been three deaths of users aged 95, 88 and 81. This is a high mortality age group under any circumstances. It isn't known if the use of Tamiflu was to treat influenza or prophylactic use. Neither Japan, the US or Canada has determined adverse reactions are due to Tamiflu, but the reports of neurobehavioral events in young persons has to be taken seriously.

Health Canada issued a predictable statement:

Although Canadians should be aware of the possibility Tamiflu may be linked to adverse reactions, there is no reason for people to be worried, said Health Canada spokesman Alastair Sinclair.

"No, Canadians shouldn't be unduly concerned," he said. (Vancouver Sun)

Obviously. Should one ever be unduly concerned? The main question here is whether we should be duly concerned. Unfortunately, drug epidemiology is difficult and requires considerable time and resources. Given the importance of this question for pandemic preparedness, we hope the investment is being made. Meanwhile Hoffman-La Roche, Tamiflu's maker, is being queried for updated safety information.

I've mentioned here several times I don't have a personal stockpile of Tamiflu. If I did, in a pandemic I would only use it prophylactically were I knowingly and definitely exposed at work or home to someone with H5N1 infection (e.g., a family member). I would hope, also, it would be used promptly by my health care provider if I were to become sick. In those cases I have no doubt about the risk benefit equation, although it might turn out the drug is without effect or I might get a rare adverse reaction. But prophylaxis of the entire population is risking adverse events without demonstrable benefit and further risks promoting drug resistance.

Health Canada has recently been under fire for tardy health warnings and this episode doesn't help. Agency insiders blame mismanagement and lack of resources. If true (and it fits the pattern of many other countries), it is a foolish savings.

So what else is new.