First confirmed case of COVID-19 in the United States is diagnosed in Snohomish County on January 20, 2020.

  • By Alan J. Stein
  • Posted 4/20/2020
  • Essay 21018
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On January 20, 2020, the first confirmed case of Coronavirus Disease 2019 in the United States is diagnosed in Snohomish County, north of Seattle. The patient is a 35-year-old man who has recently returned home after visiting family members in Wuhan, China. He ends up spending the rest of the month being cared for in isolation at the Providence Regional Medical Center in Everett, before being sent home to finish his recovery under self-quarantine. It will soon become clear that he is far from the only person in the U.S. infected with COVID-19, and within weeks the disease will be spreading rapidly in many parts of the country as it is elsewhere around the world.

It Begins

Coronaviruses are a family of viruses that can cause respiratory infections ranging from the common cold to Severe Acute Respiratory Syndrome (SARS). On December 31, 2019, a cluster of pneumonia cases of unknown cause were reported in Wuhan City in China's Hubei Province. By January 3, 2020, there were 44 patients identified, many of whom had links to the Huanan Seafood Wholesale Market. On January 7, Chinese authorities identified the cause as a novel (new) coronavirus, and the illness was named Coronavirus Disease 2019 (abbreviated as COVID-19).

On January 12, Chinese scientists publicly shared the genetic sequence of COVID-19. Based on information known at the time, the World Health Organization issued guidelines on detection, diagnosis, prevention, and control. The extent of human-to-human transmission was not yet known, but such transmission was assumed based on previous outbreaks of SARS and other similar respiratory illnesses.

By this time more suspected cases became known and, while severe cases of COVID-19 sometimes led to viral pneumonia and other acute respiratory problems, the majority of known cases were milder, with symptoms of fever, fatigue, shortness of breath, and other flu-like ailments. It wasn't until much later that scientists learned that there were already many undetected cases of people who were carrying the virus but who showed no symptoms at all. This caused the virus to spread rapidly.

It Spreads

By mid-January COVID-19 cases were confirmed in other Chinese provinces as the virus moved through the populace relatively unimpeded before travel restrictions and other social distancing measures were put into place. Deaths were also being reported. The first reported -- of a 61-year-old man in Wuhan who had underlying medical conditions -- occurred on January 9. Others soon followed and began to include victims beyond those in at-risk populations such as the elderly or those with underlying health issues.

On January 13, Thailand reported the first case outside China. The patient, a 61-year-old woman from Wuhan, did not report visiting the Huanan market. Three days later, Japan reported its first case, a 31-year-old man who had traveled to Wuhan but also had not visited the market. Two more cases were soon detected in Thailand.

On January 20, China's health ministry confirmed for the first time that COVID-19 could be transmitted between humans and the Chinese Center for Disease Control and Prevention reported that the original Wuhan coronavirus had mutated into two additional strains. That same day, South Korea reported its first case -- a Chinese woman who had flown in from Wuhan -- and the United States witnessed its first case in Snohomish County.

It Arrives

The patient in Snohomish County was a 35-year-old man whose name was not made public. He had returned to Washington on January 15 after visiting family in Wuhan. His arrival in the United States came two days before the U.S. Centers for Disease Control and Prevention (CDC) began screening passengers at New York and San Francisco, the only two cities that received direct flights from Wuhan, and at Los Angeles, where passengers came in on connecting flights.

After arriving home, the man began experiencing a dry cough, nausea, and fever, symptoms associated with COVID-19. He had seen CDC alerts about the coronavirus outbreak in Wuhan, and on January 19 he visited an urgent-care facility. Based on his symptoms and travel history, local and state health departments were contacted immediately.

Doctors using swabs retrieved samples from the patient's nasal cavity and his mouth in accordance with CDC guidelines, and after the specimens were collected the patient was sent home for isolation while being monitored by the local health department. The next day the swab-sample tests confirmed that the man was indeed infected with COVID-19.

It's Here

Health officials then alerted Providence Regional Medical Center in Everett that they were bringing the patient there for quarantine. Medical staff quickly erected a pop-up biohazard chamber used for patients with infectious diseases. The patient arrived in a mobile isolation unit and was transferred into the chamber. Doctors examined the patient via a video system that allowed them to see and speak with him.

When they had to make physical contact with the patient, doctors and nurses wore two sets of gloves and cumbersome respirator helmets that had a plastic faceguard. The patient's vitals were monitored continuously and an IV administered fluids, but after five days his condition worsened. He was placed on oxygen when he began to develop pneumonia.

Doctors consulted with the CDC and got FDA approval to administer an experimental antiviral drug called remdesivir, which had been tested in Ebola patients. The day after treatment, the patient's fever subsided. In the first week of February he was well enough to go home, although he was still being monitored and was under self-quarantine.

By then, the public already knew about this first case, having been informed on January 20, the day the patient was diagnosed. On January 22, during an interview at the World Economic Forum in Switzerland, President Donald Trump referred to the case as "one person coming in from China, and we have it under control. It's -- going to be just fine" (Calia). However, it quickly became clear that many others in the U.S. had the disease too, and it soon spread around the country. Many cities and states began to implement unprecedented closures of businesses and public areas to slow the spread of COVID-19 and a national emergency was declared on March 13.

Next: Governor Jay Inslee declares a statewide State of Emergency on February 29, 2020.


Wenjie Tan et al., "Notes from the Field: A Novel Coronavirus Genome Identified in a Cluster of Pneumonia Cases -- Wuhan, China 2019−2020," Chinese Center for Disease Control and Prevention website accessed April 10, 2020 (; Lisa Schnirring, "Report: Thailand's Coronavirus Patient Didn't Visit Outbreak Market," January 14, 2020, University of Minnesota Center for Infectious Disease Research and Policy website accessed April 12, 2020 (; Lily Kuo, "China Confirms Human-to-human Transmission of Coronavirus," The Guardian, January 20, 2020 (; Aimee Cunningham, "People Who Didn't Know They Had COVID-19 Drove Its Spread in China," Science News, March 17, 2020 (; "S. Korea Reports 1st Confirmed Case of China Coronavirus," January 20, 2020, Yonhap News Agency website accessed April 10, 2020 (; Michelle L. Holshue et al., "First Case of 2019 Novel Coronavirus in the United States," New England Journal of Medicine, March 5, 2020, available at National Institutes of Health website accessed April 10, 2020 (; Denise Grady, "Three U.S. Airports to Check Passengers for a Deadly Chinese Coronavirus," The New York Times, January 17, 2020 (; "Snohomish County Man Has the United States' First Known Case of the New Coronavirus," The Seattle Times, January 21, 2020 (; Ryan Blethen, "What It Was Like for Doctors and Nurses at an Everett Hospital to Treat the Nation's First Novel Coronavirus Patient," Ibid., February 14, 2020; Jim Tankersley and Emily Cochrane, "Trump Declares National Emergency to Deal with Coronavirus," Ibid., March 13, 2020; Mike Calia, "Full Interview: President Trump Discusses Trade, Impeachment, Boeing and Elon Musk with CNBC in Davos," CNBC, January 22, 2020 (; World Health Organization website accessed April 20, 2020 (; Centers for Disease Control and Prevention website accessed April 20, 2020 (

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