According to reports, more than 1,000 users on social media in the United States said that they or their family members and friends had been infected with the coronavirus in December 2019 or even earlier. Among them, at least more than 100 real-name users seriously recounted their infection experiences, and the symptoms they described were very close to COVID-19.
A Washington resident named Jamie Kettenhofen tweeted on December 22, 2020: "My wife and doctor are convinced that I had COVID-19 on October 1, 2019. It was terrible, and they didn't know what it was at the time. I was isolated in the intensive care unit for 10 days, with low blood oxygen levels, (lung) X-rays like shattered glass, and they couldn't determine viral and bacterial pneumonia after multiple tests."