MSK Library Guides: Respiratory Viruses: Pandemic Influenza

What is Pandemic Influenza?

Pandemic Influenza

An influenza pandemic is a global outbreak of a new influenza A virus. Pandemics happen when new (novel) influenza A viruses emerge which are able to infect people easily and spread from person to person in an efficient and sustained way.

How is Pandemic Influenza Different from Seasonal Influenza?

	Seasonal Influenza	Pandemic Influenza
How often does it happen?	Happens annually and usually peaks between December and February	Rarely happens (three times in 20th century)
Will most people be immune?	Usually some immunity from previous exposures and influenza vaccination	Most people have little or no immunity because they have no previous exposure to the virus or similar viruses
Who is at risk for complications?	Certain people are at high-risk for serious complications (infants, elderly, pregnant women, extreme obesity and persons with certain chronic medical conditions)	Healthy people also may be at high risk for serious complications
Where can I get medical care?	Health care providers and hospitals can usually meet public and patient needs	Health care providers and hospitals may be overwhelmed Alternate care sites may be available to meet public and patient needs
Will a vaccine be available?	Vaccine available for annual flu season Usually, one dose of vaccine is needed for most people	Although the US government maintains a limited stockpile of pandemic vaccine, vaccine may not be available in the early stages of a pandemic Two doses of vaccine may be needed
Will antivirals be available?	Adequate supplies of antivirals are usually available	Antiviral supply may not be adequate to meet demand
How many people could get sick and suffer complications?	Rates of medical visits, complications, hospitalizations and death can vary from low to high CDC estimates that flu-related hospitalizations since 2010 ranged from 140,000 to 710,000, while flu-related deaths are estimated to have ranged from 12,000 to 56,000.	Rates of medical visits, complications, hospitalizations and death can range from moderate to high Number of deaths could be much higher than seasonal flu (e.g. The estimated U.S. death toll during the 1918 pandemic was approximately 675,000)
What impact will it have on schools and workplaces?	Usually causes minor impact on the general public, some schools may close and sick people are encouraged to stay home Manageable impact on domestic and world economies	May cause major impact on the general public, such as travel restrictions and school or business closings Potential for severe impact on domestic and world economies

Pandemic Influenza Resources

Influenza Risk Assessment Tool (IRAT)
The Influenza Risk Assessment Tool (IRAT) is an evaluation tool developed by CDC and external influenza experts that assesses the potential pandemic risk posed by influenza A viruses that currently circulate in animals but not in humans. The IRAT assesses potential pandemic risk based on two different scenarios: “emergence” and “public health impact.”
Pandemic Influenza Tools
CDC’s pandemic influenza preparedness efforts include ongoing surveillance of human and animal influenza A viruses, risk assessments of influenza A viruses with pandemic potential, and the development and improvement of preparedness tools that can aid public health practitioners in the event of an influenza pandemic.
Topic Collection: Influenza Epidemic/Pandemic
HSS: Healthcare Emergency Preparedness Information Gateway
Systematic Assessment of Multiple Routine and Near Real-Time Indicators to Classify the Severity of Influenza Seasons and Pandemics in the United States, 2003–2004 Through 2015–2016
Biggerstaff M, Kniss K, Jernigan DB, et al. Systematic Assessment of Multiple Routine and Near Real-Time Indicators to Classify the Severity of Influenza Seasons and Pandemics in the United States, 2003-2004 Through 2015-2016. Am J Epidemiol. 2018;187(5):1040-1050.