Although pandemics occur infrequently, planning and preparing for a pandemic is important to ensure an effective response. Planning for and responding to a pandemic is complex and pandemics can affect everyone in a community. Therefore, public health officials, healthcare professionals, researchers, and scientists in the United States and across the world are working together to plan and prepare for possible pandemics. Many resources are available to help international, national, state, and local governments, public health and healthcare professionals, corporations, and communities develop pandemic preparedness plans and strengthen their capabilities to respond to different pandemic scenarios.
Pandemic Flu
Scientists around the globe continue to warn the public about the risk of a potential pandemic influenza outbreak, which typically strikes three to four times a century. Pandemic flu is caused by a strain of the flu virus that is capable of producing severe disease and spreading rapidly person-to-person worldwide. Unlike the seasonal flu, a pandemic flu virus poses a novel threat. Since humans have no previously developed immunity against pandemic flu, this virus strain puts most people at high risk of infection. This could result in a large percentage of the world's population being infected by a rapidly spreading virus in a very short period of time. Though considerable progress has been made in the last few years, much more must be done to prepare for a pandemic.
Experts predict a severe pandemic flu outbreak could result in up to 1.9 million deaths in the United States, approximately 9.9 million Americans needing to be hospitalized, and an economic recession with losses of over $680 billion to the U.S. Gross Domestic Product.
H1N1
The U.S. Public Health Emergency for 2009 H1N1 Influenza expired on June 23, 2010. On August 10, 2010, the World Health Organization International Health Regulations (IHR) Emergency Committee declared an end to the 2009 H1N1 pandemic globally. For information about CDC’s response to the 2009 H1N1 pandemic, visit The 2009 H1N1 Pandemic: Summary Highlights, April 2009-April 2010. Internationally, 2009 H1N1 viruses and seasonal influenza viruses are co-circulating in many parts of the world. It is likely that the 2009 H1N1 virus will continue to spread for years to come, like a regular seasonal influenza virus.
Avain Influenze (H5N1) & (H7N9) - (Bird Flu)
Avian influenza virus usually refers to influenza A viruses found chiefly in birds, but infections can occur in humans. The risk is generally low to most people because the viruses do not usually infect humans. However, confirmed cases of human infection have been reported since 1997.
Although avian influenza A viruses usually do not infect humans, rare cases of human infection with avian influenza A viruses have been reported. Most human infections with avian influenza A viruses have occurred following direct contact with infected poultry. Human clinical illness from infection with avian influenza A viruses has ranged from eye infections (conjunctivitis) to severe respiratory disease (pneumonia) to death.
Since November 2003, nearly 400 cases of human infection with highly pathogenic avian influenza A (H5N1) viruses have been reported by more than a dozen countries in Asia, Africa, the Pacific, Europe, and the Near East. Highly pathogenic avian influenza A (H5N1) viruses have never been detected among wild birds, domestic poultry, or people in the United States.