For most people, influenza, or flu, causes fever, coughing, headaches, aches and pains, and fatigue. Flu illness can escalate and develop into life-threatening complications like pneumonia and respiratory failure. Each year scientists predict which strains of the flu virus are likely to affect which areas of the world. Vaccines are developed and then distributed annually to help build immunity against seasonal flu viruses so as to protect against flu and its potentially serious complications.
A flu pandemic can occur when a novel, non-human strain of the flu virus emerges, and a given population has little or no immunity against it. If the virus spreads throughout a given population and then spreads across national or geographical boundaries, it becomes a global threat— a flu pandemic.
Flu pandemics have happened four times before in recent history—in 1918, 1957, 1968, and 2009. And, the world is currently responding to the COVID-19 pandemic, and national health systems are being put to the test.
A key element of response is being able to distribute and administer vaccine efficiently and effectively. Influenza programs can support readiness now and in the future.
For more information on flu or pandemics, please visit:
Influenza News from the CDC
CDC International Influenza Updates
CDC Seasonal Flu Updates
- CDC and Representatives from Across Southeast Asia Meet in Bangkok for Workshop on Avian Influenzaon May 15, 2023 at 3:51 pm
CDC and Representatives from Across Southeast Asia Meet in Bangkok for Workshop on Avian Influenza
- Human Infection with highly pathogenic avian influenza A(H5N1) virus in Chileon April 17, 2023 at 6:31 pm
This addendum to Technical Report: Highly Pathogenic Avian Influenza A(H5N1) Viruses, originally published on March 17, 2023, provides a summary of the case and the genomic analysis of the virus from the first human case of H5N1 reported in Chile.
- New CDC Study Identifies Timing of Seasonal Flu Epidemics for 25 Countries in Africaon April 14, 2023 at 4:00 am
A new CDC study published in the Lancet Global Health looked at 10 years of laboratory flu data from 25 African countries in order to provide new, policy-relevant information about when to expect annual flu epidemics.
- Human Infection with Avian Influenza A(H3N8) Virus Reported by Chinaon April 10, 2023 at 6:58 pm
Human Infection with Avian Influenza A(H3N8) Virus Reported by China
- Chile Reports First Case of H5N1on March 30, 2023 at 6:51 pm
Chile Reports First Case of H5N1