Influenza Planning and Response

Influenza poses one of the world’s greatest infectious disease challenges. CDC programs protect the United States from seasonal influenza and pandemic influenza, when a new flu virus emerges that can infect people and spread globally.

Influenza is always changing
  • Seasonal flu causes sickness and death

    Flu viruses change constantly, from season to season and sometimes during the season.

  • Flu vaccines must be updated frequently to keep up with these changes.
  • Each winter, influenza causes millions of illnesses, hundreds of thousands of hospitalizations, and thousands of deaths.
Novel influenza viruses are always emerging
  • Novel influenza viruses are always emerging

    Some influenza viruses don’t spread in people, but spread in animals, especially wild birds and pigs.

  • Animal influenza viruses can jump to people and cause a pandemic.
  • Recently, more instances of animal influenza viruses infecting people have been reported.
  • People may have little or no immunity to pandemic influenza so the consequences can be much greater. thousands of deaths.
An influenza pandemic can emerge anywhere and spread globally
  • An influenza pandemic can emerge anywhere and spread globally

    Four influenza pandemics have occurred in the past 100 years.

  • The 1918-19 flu pandemic was the most severe, killing 675,000 Americans and 50 to 100 million people worldwide.
  • During a pandemic:
    • medicine may be in short supply
    • vaccines may not be ready immediately
    • hospitals may be overwhelmed
    • schools and businesses may close

What CDC does to protect Americans from influenza threats

CDC uses its scientific expertise and resources to address the continuing threat posed by seasonal and pandemic influenza. Key CDC activities that protect people against both seasonal and pandemic influenza include:

Monitoring Influenza Viruses
Icon: monitoring flu

Works with domestic and global health partners to monitor both human and animal influenza viruses to know what and where viruses are spreading and what kind of illness they are causing.

Studying Viruses in the Lab
Icon: vaccine development

Studies both human and animal influenza viruses in the laboratory to better understand the characteristics of these viruses, including conducting genetic sequencing on more than 6,000 viruses each year.

Improving Testing and Diagnostics
Icon: studying flu

Develops and distributes diagnostic tests and provides materials to state, local, territorial, and international laboratories so that they can detect and characterize influenza viruses.



Leading Planning and Preparedness
Icon: improving testing

Leads influenza planning and preparedness on a national and global level. CDC works with the World Health Organization and partner countries in pandemic planning efforts. Domestically, CDC supports the development and use of community mitigation measures and medical countermeasures to minimize the impact of a pandemic.

Supporting Vaccine Development
Icon: planning and preparedness

Assist global and domestic experts each year in choosing which viruses to include into the seasonal vaccine and guides prioritization of pandemic vaccine development. CDC develops candidate viruses used by manufacturers to make flu vaccines.

Funding and Technical Assistance
Icon: funding and assistance

Provides direct support to state, local, and territorial public health departments for influenza surveillance and laboratory work. Globally, CDC provides support to more than 50 countries for building surveillance and laboratory capacity in order to find emerging influenza threats and respond to them.

Improving Tools to Prevent and Control
Icon: improving tools

Evaluates the effectiveness of vaccines and drugs to prevent and treat influenza. Regularly reviews and updates guidelines for use of these vaccines and drugs.

Providing Timely and Accurate Information
Icon: timely and accurate information

Informs health care providers and public about influenza prevention and control measures. CDC works with businesses, schools, communities, and others to plan for and address flu threats.