This Day In History: December 31

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On New Year’s Eve 2019, China’s Wuhan government reports a cluster of cases of what it calls pneumonia. That virus causes an infectious disease later known as COVID-19, which quickly morphs into a global pandemic that causes nearly 7 million deaths.

The announcement came from the Wuhan Municipal Health Organization in China’s Hubei Province. Just a few days later, 44 Chinese citizens were reporting this “pneumonia of unknown etiology,” and of those, 11 had become seriously ill. National authorities reported that all patients were isolated and receiving treatment in Wuhan medical institutions. They had symptoms including fever, difficulty breathing and invasive lesions on their lungs.

The unidentified coronavirus spread explosively in China, and about three weeks after the initial announcement—on January 20, 2020—the Chinese government started to call the virus a Class B infectious disease, and officials implemented a level-one public-health emergency response. This coronavirus was labeled SARS-CoV-2, because it was genetically similar to the SARS virus that broke out in 2003. Five main mutations of SARS-CoV-2 emerged in the next few years: Alpha, Beta, Gamma, Delta and Omicron.

That December 31 is the first reported date on the World Health Organization’s earliest COVID-19 timeline. Nobody knew what was coming or how bad it would get, but by March 2020, the pandemic started wreaking devastation in the United States. Businesses and schools shut down around the country, people started wearing masks and practicing social distancing and fierce controversies erupted among citizens about public health measures. In the U.S., more than 103 million COVID-19 cases would be reported in the next three years, and about 1.14 million Americans would die from the pandemic.

Although many studies have been done to determine the origin of the virus—suspected to originate from animals at Wuhan’s “wet markets”—none has been conclusive.