Health officials and researchers are still learning about COVID-19.

According to the U.S. Centers for Disease Control and Prevention (CDC), the virus is believed to be transmitted primarily from person to person among people who are in close contact (less than six feet, 1.83 meters), through of respiratory drops produced when an infected person coughs or sneezes.

Health officials and researchers are still determining the incubation period for the virus, or the time between infection and the onset of symptoms, according to an analysis by the US Congress. The CDC is using 14 days as the external limit for the incubation period, which means the agency expects someone infected to show symptoms within that period.

WHO Coronavirus Disease (COVID-19) Dashboard

Data last updated: 2020/5/12, 6:42 pm CEST

According to the same analysis, the CDC has confirmed that asymptomatic cases (infected individuals with no symptoms) can transmit the virus, although «their role in transmission is not yet known.»

A study of the 3,711 passengers on the Diamond Princess cruise ship found that 712 people (19.2% of cruise ship passengers) tested positive for COVID-19. Almost half (331) of the positive cases were asymptomatic at the time of the test.

COVID-19

In December 2019, a new disease called COVID-19 emerged in China and quickly turned into a global pandemic.

The disease has important consequences for global health, external relations, the global economy and global security.

International institutions and country governments are taking a variety of responses to address these challenges.

The origin of COVID-19 is unknown, although genetic analysis suggests an animal source. On December 31, 2019, the Chinese government notified the World Health Organization (WHO) of cases of pneumonia from unknown causes in Wuhan, China.

On January 7, 2020, Chinese scientists isolated a previously unknown coronavirus in patients, and on January 12, scientists made their genetic sequence available to WHO and international partners.