The use of prescription antiviral drugs to treat and prevent infection will be an important component of a pandemic influenza response. While current antiviral drug use strategies and publicly maintained stockpiles are targeted primarily for treatment of persons with pandemic illness, expanded antiviral drug production has allowed additional strategies to be considered. As guidance, this document does not create a requirement; rather, it defines a prudent strategy for antiviral drug stockpiling and use that can contribute to a more effective pandemic response.
The guidance on antiviral use is based on the national pandemic response goals of slowing the spread of pandemic disease, reducing impacts on health, and minimizing societal and economic disruption. The working group recommends the following strategies and settings for antiviral use to meet these goals:
- Containing or suppressing initial pandemic outbreaks overseas and in the United States with treatment and post-exposure prophylaxis (PEP) among individuals identified as exposed to pandemic influenza and/or geographically targeted prophylaxis in areas where exposure may occur;
- Reducing introduction of infection into the United States early in an influenza pandemic as part of a risk-based policy at U.S. borders;
- Treatment of persons with pandemic illness who present for care early during their illness and would benefit from such treatment;
- Prophylaxis of high-risk healthcare workers and emergency services personnel for the duration of community pandemic outbreaks;
- Post-exposure prophylaxis of workers in the healthcare and emergency services sectors who are not at high exposure risk, persons with compromised immune systems who are less likely to be protected by pandemic vaccination, and persons living in group settings such as nursing homes and prisons if a pandemic outbreak occurs at that facility.
Antiviral drugs are being stockpiled by HHS as part of the Strategic National Stockpile, (SNS) and by States. The current public sector stockpile target is 81 million drug regimens: 6 million regimens for containment and for slowing the entry of pandemic disease into the United States, and 75 million regimens for treatment. Implementation of recommendations for prophylaxis of healthcare and emergency services workers who have high-risk exposures and for PEP in recommended settings will depend largely on private sector organizations and businesses purchasing and stockpiling antiviral drugs for their employees. The working group encourages governments, healthcare organizations and other employers, and families and individuals as appropriate, to purchase and stockpile sufficient antiviral drug supply to support recommended antiviral drug use strategies and to plan for effective implementation at the time of a pandemic as part of comprehensive pandemic planning and preparedness.
In addition to the national recommendations on treatment and prophylaxis, businesses that provide goods or services essential to community health, safety, or well-being (“critical infrastructure” sectors) should strongly consider antiviral prophylaxis for critical workers as part of comprehensive pandemic preparedness planning, especially those workers who are individually critical and whose absence would jeopardize provision of essential services. Other employers may consider antiviral prophylaxis for workers to maintain business continuity or protect employees. PEP for household contacts of persons with pandemic illness will reduce their risk of infection and may decrease overall rates of pandemic disease in communities. Despite these potential benefits, however, further work is needed to assess the feasibility of this strategy and identify approaches for purchasing and stockpiling the antiviral drugs to support its implementation. Therefore, the working group makes no recommendation for household antiviral PEP at this time.
Antiviral medications from the SNS, other than those targeted for containment and use at U.S. borders, will be allocated pro rata and delivered to Public Health Emergency Preparedness Project Areas (includes 50 States, 4 major metropolitan areas, and 8 U.S. territories) when a pandemic occurs. The working group recommends that public sector antiviral drug supply be prioritized for treatment of all persons who may benefit from therapy based on assessment of medical need. Treatment is preferred to prophylaxis in settings of limited antiviral drug supply; targeting some antiviral drug supply for prophylaxis and prioritizing treatment for certain groups would raise significant ethical and logistical challenges. Effective implementation of community mitigation strategies to reduce rates of illness and greater accuracy in diagnosing pandemic influenza illness would reduce antiviral drug needs, potentially leading to an ability to provide some prophylaxis while maintaining a treatment policy. Among prophylactic antiviral drug uses, protecting front-line healthcare and emergency services personnel is the top priority.
Ongoing discussions with stakeholders and the public are important as part of a transparent process and to move forward in addressing implementation issues. Rapid implementation of these strategies during a pandemic will pose substantial challenges. Periodic reassessment of national antiviral drug guidance will be important based on scientific and technological advances. Strategies also should be reassessed when a pandemic occurs to take into account the characteristics of the virus, epidemiology of disease, and impacts on society.