What is COVID-19?
COVID-19 is the new respiratory disease spreading around the world and it is caused by a coronavirus. COVID-19 is short for Coronavirus Disease 2019.
The 2019 Novel Coronavirus (2019-nCoV) often referred to as COVID-19 or more simply, the coronavirus is a severe acute respiratory syndrome (SARS-CoV-2) that was newley identified in Wuhan City, Hubei Province, China. Since the first cases were reported, the outbreak has rapidly spread through China and many locations worldwide. Coronaviruses are a large family of viruses that can cause illness in both humans and animals. The illnesses brought about from the coronavirus have ranged from the common cold (ex. Respiratory syndrome, fever, cough, etc.) to more severe sicknesses such as pneumonia and severe acute respiratory syndrome .
PLEASE NOTE: The virus that causes COVID-19 and the one that caused the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003 are related to each other genetically, but the diseases they cause are quite different. SARS was more deadly but much less infectious than COVID-19, the SARS that may be caused by the coronavirus is a different strain of this so please keep this in mind.
As of April 02, 2020 there have been over 920,000 in at least 180 countries and territories with the highest numbers being in America, Italy, Spain, China and Germany in that order.
In comparison with other countries, Japan is relatively low on the list with only 2,412 cases, and 67 deaths. In our prefecture of Yamanashi there have only been 9 confirmed cases.
There are three parameters to understand in order to assess the magnitude of the risk posed by this novel coronavirus:
Transmission Rate (Ro) - number of newly infected people from a single case
World Health Organization (WHO)'s estimated (on Jan. 23) Ro to be between 1.4 and 2.5.
Case Fatality Rate (CFR) - percent of cases that result in death
3.4% Mortality Rate estimate by the WHO as of March 3
Determine whether asymptomatic transmission is possible
As of now it has been discovered that coronavirus can be spread from someone who carries the virus but shows no symptoms. Thus many governments across the world have decided on a two week incubation period. However, there have been outlier cases such as people who left the diamond princess cruise ship after incubation, returned home and tested positive, as well as a case where someone tested positive in China after 27 days.