|
| ||||||||
| ||||||||
|
Tamiflu® (Oseltamivir Phosphate) Use in Pandemic Avian Flu [download PDF] In a Pandemic it will be Very Difficult to Distribute Oseltamivir to Sick People in Time Oseltamivir must be administered within 1-2 days of onset of symptoms to be effective. It is most effective when given within the first few hours of symptoms. Therefore, it is important that plans are made to get oseltamivir to sick people in time to be useful. Difficulties in Diagnosing Influenza will Lead to Wide Use of Oseltamivir During a pandemic, it will be difficult to rapidly differentiate between actual cases of influenza and people who are sick with other diseases, so oseltamivir will be distributed widely. Practically, unless effective rapid diagnostic tests for avian influenza are available in doctors' offices and hospitals, oseltamivir will be given out to many people who prove not to have avian influenza. Some People with Influenza may not Respond to Treatment with Oseltamivir Experience shows that influenza viruses may develop a resistance to antiviral medications. It is possible that resistance may develop more frequently during times of wide-scale use. Oseltamivir's Ability to Prevent Avian Influenza Infection in Humans is Untested Although oseltamivir has been demonstrated as safe and effective for preventing common cases of the flu, it has not been tested in humans against avian influenza or during a pandemic. Studies in mice have shown that oseltamivir may prevent infection with H5N1, but how exactly it will protect humans against a strain of H5N1 that has acquired the ability to cause a pandemic is not known. Limited quantities of other antiviral medications might be available for use, but like oseltamivir, these medications also have not been tested in humans against avian influenza, and it is not known how effective they will be. The Current Stockpile of Oseltamivir is Not Enough to Cover High Priority Groups Many have talked about giving oseltamivir to healthy healthcare workers, public health and emergency responders, and other critical personnel to prevent them from becoming sick during a pandemic so that they can continue to perform their vital functions. This strategy (called prophylaxis) is different from using oseltamivir to treat people once they become sick and would require that people continue to take oseltamivir for extended periods of time, using more of the oseltamivir stockpile. The U.S. does not have nearly enough antiviral medications to support a strategy of wide-scale prophylaxis. We May Have Fewer Doses of Oseltamivir than We Think The efficacy of oseltamivir depends on the virulence of the particular strain of virus. Studies show that to prevent cases of avian influenza with oseltamivir, we may need to give more of it for a longer period of time than the standard recommendation. This means we may not be able to treat as many people with current supplies as we think. Current Oseltamivir Production Capacity is Not Sufficient There is currently only one plant in the world that makes oseltamivir. As many countries around the world are racing to stockpile sufficient quantities of the drug for their citizenry, there is an international backlog of orders. Expanding manufacturing capacity will take several years. Prepared by the Center for Biosecurity of UPMC, for a briefing on Capitol Hill, October 12, 2005, co-sponsored by Trust for America's Health (TFAH), Senator Barack Obama (D-IL), Senator Olympia J. Snowe (R-ME), Congresswoman Nita M. Lowey (D-NY), the Infectious Diseases Society of America (IDSA), and the Center for Biosecurity of UPMC. |