ARI SHAPIRO, host:
One pressing healthcare issue every winter is the flu. It kills thousands of people, often small children, frail seniors and people with chronic diseases. In recent years, doctors have relied on the drug Tamiflu to treat serious flu cases. As NPR's Richard Knox reports, most of the flu viruses circulating in America so far this season are resistant to Tamiflu.
RICHARD KNOX: The Centers for Disease Control and Prevention has tested about 120 flu viruses so far this winter. Dr. Joseph Brasee of the CDC says 73 of them turned out to be a type called H1N1.
Dr. JOSEPH BRASEE (Chief, Epidemiology and Prevention, National Center for Immunization and Respiratory Diseases, Center for Disease Control and Prevention): And of those 73 strains, 72 were 99-percent found to have the mutation that makes it resistant.
KNOX: Resistant to the drug Tamiflu. Just before Christmas, the CDC warned doctors that if their local public health officials say the H1N1 strain is making the rounds in their community, they should assume that Tamiflu won't work against it.
Dr. BRASEE: We were worried about the possibility that a doctor might be treating a patient for flu, give them Tamiflu, because that's what they usually give, not realizing that there are some resistant viruses spreading.
KNOX: Dr. Mike Osterholm says the doctor has to make a stab in the dark about what flu strain is making his patients sick.
Dr. MICHAEL T. OSTERHOLM (Director, Center for Infectious Disease Research and Policy, University of Minnesota): Unfortunately, we don't have a good test that would automatically tell us not only do they have flu, but is it specifically, too, this H1N1 type?
KNOX: Osterholm leads the Center for Infectious Disease Research and Policy in Minneapolis. He says losing Tamiflu leaves doctors and patients with few options. For instance, doctors can't use an alternate flu drug called Relenza on children under seven. There are two other alternatives, Amantadine and Rimantadine, but over the past couple of years, their use has declined sharply because another common flu strain has become resistant to them. So, now, when doctors prescribe these drugs, they can't always get them.
Dr. OSTERHOLM: We are already learning of some shortages that are occurring out there, where apparently the supply of either or both of those drugs was not anticipated to be needed this year, and so that some of the pharmacies have not been able to get it on the day that it's requested.
KNOX: The worldwide emergence of flu viruses as resistant to Tamiflu causes another, bigger, worry. What if the Tamiflu-resistant gene jumped from the H1N1 virus into H5N1, the deadly bird-flu virus that still circulates in Asia and the Middle East?
Dr. OSTERHOLM: We're clearly seeing H1N1 in Asia that could very easily provide some type of jumping mechanism if they were to combine with H5N1. It has not been demonstrated yet, and clearly, that's one that people are looking at or looking for, but it hasn't happened to date that we're aware of.
KNOX: Experts still fear the bird-flu virus might learn how to spread in humans, touching off a devastating pandemic. If that happens, the world is counting on big stockpiles of Tamiflu to save lives. Richard Knox, NPR News.