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Infectious disease emergency preparedness

Learn more about preparing for infectious diseases.


A new coronavirus emerged in late 2019 and was quickly dubbed COVID-19. Coronaviruses are a large family of viruses. They usually cause mild respiratory illnesses such as the common cold. There have been coronaviruses that have caused more severe illness, such as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). COVID-19 is a new coronavirus that had not been seen in humans prior to December 2019.

As with any newly emerging infectious disease, knowledge evolves with time. Early on, it is difficult to know the source of the disease, the ways in which it spreads and how effectively it spreads from person to person, and the spectrum of illness - how severe the infection is.

Check Public Health - Seattle & King County‚Äôs COVID-19 webpage for information and updates.

Pandemic flu

A pandemic flu is a new influenza virus that is much more severe than those experienced in a typical flu season. Unlike a typical flu strain, humans would have no or little natural resistance to the new virus.

During the last century, four influenza pandemics occurred that spread worldwide within a year. Of these, the flu pandemic of 1918 was the most severe. It caused more than 500,000 deaths in the United States and more than 40 million deaths around the world. The H1N1 pandemic of 2009-2010 was far less severe. But it is estimated to have caused more than 12,000 deaths in the United States, according to the Centers for Disease Control and Prevention (CDC).

Learn more by visiting the Public Health - Seattle & King County website