On Dec. 31, 2019, the Chinese city of Wuhan reported an outbreak of pneumonia from an unknown cause. The outbreak was found to be linked to the Hunan seafood market because of a shared history of exposure by many patients. After a full-scale investigation, China’s Center for Disease Control activated a level 2 emergency response on Jan. 4, 2020. A novel coronavirus was officially identified as a causative pathogen for the outbreak.1
Coronavirus, first discovered in the 1960s, is a respiratory RNA virus, most commonly associated with the “common cold.” However, we have had two highly pathogenic forms of coronavirus that originated from animal reservoirs, leading to global epidemics. This includes SARS-CoV in 2002-2004 and MERS-CoV in 2012 with more than 10,000 combined cases. The primary host has been bats, but mammals like camels, cattle, cats, and palm civets have been intermediate hosts in previous epidemics.2
The International Committee on Taxonomy of Viruses named the 2019-nCoV officially as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease, COVID-19, on Feb. 11, 2020.3 Currently, the presentation includes fever, cough, trouble breathing, fatigue, and, rarely, watery diarrhea. More severe presentations include respiratory failure and death. Based on the incubation period of illness for Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) coronaviruses, as well as observational data from reports of travel-related COVID-19, CDC estimates that symptoms of COVID-19 occur within 2-14 days after exposure. Asymptomatic transmission is also documented in some cases.4
On Jan. 13, the first case of COVID-19 outside of China was identified in Thailand. On Jan. 21, the first case of COVID-19 was identified in the United States. On Jan. 23, Chinese authorities suspended travel in and out of Wuhan, followed by other cities in the Hubei Province, leading to a quarantine of 50 million people. By Jan. 30, the World Health Organization had identified COVID-19 as the highest level of an epidemic alert referred to as a PHEIC: Public Health Emergency of International Concern. On Feb. 2, the first death outside China from coronavirus was reported in the Philippines. As of March 4 there have been 95,000 confirmed cases and 3,246 deaths globally. Within China, there have been 80,200 cases with 2,981 deaths.5
Cases have now been diagnosed in increasing numbers in Italy, Japan, South Korea, Iran, and 76 countries. Of note, the fatalities were of patients already in critical condition, who were typically older (more than 60 years old, especially more than 80) and immunocompromised with comorbid conditions (cardiovascular disease, diabetes, chronic respiratory disease, cancer).6 To put this in perspective, since 2010, CDC reports 140,000-810,000 hospitalizations and 12,000-61,000 deaths from the influenza virus annually in the US.7
The current situation in the United States
In the United States, as of March 4, 2020, there are currently 152 confirmed cases in 16 states. The first U.S. case of coronavirus without any of the travel-related and exposure risk factors was identified on Feb. 27 in California, indicating the first instance of community spread.8 The first death was reported in Washington state on Feb. 28, after which the state’s governor declared a state of emergency.9 On March 1, Washington state health officials investigated an outbreak of coronavirus at a long-term nursing facility in which two people tested positive for the disease, heralding the probable first nosocomial transmission of the virus in the United States. Since then, there have been 10 deaths in Washington state related to the coronavirus.