also known as M2 inhibitors, and neuraminidase inhibitors.1 The use of adamantanes is limited due both to their toxicity and the rapid development of viral resistance to this class of drugs. The neuraminidase inhibitors include oseltamivir and zanamivir. These were first approved by the Food and Drug Administration in 1999 for treatment of influenza in adults and oseltamivir also was approved for prevention in individuals 12 years of age and older. In 2005, oseltamivir was approved for prevention of influenza in children under age 12 but no younger than 1 year. In 2006, zanamivir was approved for prophylaxis in adults and children age 7 and older. Antiviral medications consisting largely of neuraminidase inhibitors are currently stockpiled by government at the federal, state, and local levels, and to a limited extent by the private sector, including some employers, health care organizations, and individuals.
Public health agencies began thinking about and planning for mass dispensing of medications and administration of vaccine for a variety of public health emergencies in the 1990s, and with added intensity in late 2001. The public health community has considerable experience with plans and exercises focusing on the distribution and dispensing of antibiotics such as ciprofloxacin and doxycycline in response to deliberate dispersal of a pathogen such as the anthrax bacillus, cause of a non-transmissible disease. Until recently, somewhat less attention has been paid to antiviral dispensing for pandemic influenza, a public health emergency that would pose some different challenges. Single-point chemoprophylaxis after the deliberate dispersal of a pathogen would be fairly straightforward. The spread of pandemic influenza would require ongoing dispensing for different purposes (i.e., treatment, post-exposure prophylaxis, or prophylaxis for the duration of the outbreak), but supplies are unlikely to be adequate for all potential uses. Finally, unlike some types of pathogens (anthrax, brucellosis, tularemia), influenza is transmissible from person to person, and this has implications for the setting and mechanism used to dispense drugs.
There are many unknowns about an influenza pandemic, including when and where a new pandemic strain will emerge, the pattern of its spread, the attack rate and the case-fatality rate, the segments of the population most affected by it, and so on. Furthermore, although neuraminidase inhibitors have been proven to be effective in treating and preventing