Medical Health

Bird flu is transmitted from birds to birds, not birds to humans. Actual human infections are pretty rare. And when and if it does mutate into a virus that can be transmitted to humans, drugs like Tamiflu (oseltamivir) probably won’t work anymore, because the drug was designed for the specific virus type that is transmitted bird to bird.

In fact it was recently reported that there has been an increase in influenza resistance to the drug Tamiflu (oseltamivir). Although previously less that 1% of influenza viruses were resistant to Tamiflu, now as many as 13% of influenza viruses are resistant. As quoted in The Star of Canada on January 29, 2008, "The European Centre for Disease Control has reported that laboratory analysis of 148 H1N1 flu viruses so far this season turned up 19 viruses with a mutation on the neuraminidase protein - the N in a flu virus’s name - at position 274." All of these resistant strains were in the human influenza virus. The experts were quoted as saying that they were "surprised" that the virus could mutate to a form that is transmissable to humans and still be viable.

What about for the regular flu? Tamiflu (and Zanamivir) are neuraminidase inhibitors; they prevent replication of influenza A and B viruses by interfering with the production and release of virus from cells that line the respiratory tract. They both need to be taken within 48 hours of the onset of flu symptoms to be useful. If you get the flu, Tamiflu will reduce the number of days you have symptoms from about seven to about five, i.e. not a very big deal. And in terms of prevention, they cut your risk by about half. Most people don’t want to take a drug all the time to prevent flu. And if you take it after someone in your house gets sick, it’s too late to prevent the flu. Side effects of both medications include swelling of the sinuses, diarrhea, nausea and vomiting. Patients with asthma or COPD may experience breathing problems. The Japanese drug regulatory agency has reported 64 cases of neuropsychiatric side effects, including "impaired consciousness, abnormal behaviors, hallucinations and other psychological and neurological symptoms" associated with Tamiflu, including two suicides. There have also been reports of seizures.

Bottom line is that there isn’t much point in stocking up on bird flu drugs. Better to wait until there is a virus that can be transmitted human to human and get a drug that works for that.