(Reuters) - An outbreak of a new coronavirus that began in the central Chinese city of Wuhan has killed 26 people and infected more than 800 globally.

FILE PHOTO: People wearing masks walk through an underground passage to the subway in Beijing, China January 21, 2020. REUTERS/Jason Lee

The virus has caused alarm because it is still too early to know just how dangerous it is and how easily it spreads between people. And because it is new, humans have not been able to build any immunity to it.

Here is what we know so far:

** There were 830 confirmed cases and 26 people had died in China, the National Health Commission said.

** China is to take stricter and more targeted measures to curb the spread, state television reported, citing a State Council meeting on virus control on Friday.

** The previously unknown strain is believed to have emerged late last year from illegally traded wildlife at an animal market in Wuhan.

** Thailand has five cases, Singapore and Taiwan three, Japan, Vietnam, South Korea and the United States with two apiece, and Nepal with one.

** The WHO said that while the outbreak was an emergency for China, it was not yet a global health emergency.

** Symptoms include fever, cough and difficulty breathing.

** China says the virus is mutating and can be transmitted through human contact.

* Those most affected are older people and those with underlying health conditions.

** Three research teams are to start work on developing potential vaccines, the Coalition for Epidemic Preparedness Innovations said. The plan is to have at least one potential vaccine in clinical trials by June.

** Preliminary research suggests the virus was passed to humans from snakes, but Chinese government medical adviser Zhong Nanshan has also identified badgers and rats as possible sources.

** Wuhan, a city of 11 million, is under severe travel restrictions, with urban transport shut and outgoing flights suspended.

** China has advised people to avoid crowds and 10 cities in the central province of Hubei, where Wuhan is located, have suspended some transport, the Hubei Daily reported.

** Beijing closed tourist access to the Forbidden City and cancelled large gatherings, including two Lunar New Year temple fairs, and closed part of the Great Wall.

** Walt Disney Co’s Shanghai Disney Resort will be closed from Saturday.

** McDonald’s suspends business in five cities in Hubei.

** Airports around the world have stepped up screening.

** China’s central bank is temporarily raising the upper limit on small bank batch payments to 500 million yuan ($72.42 million) until Jan. 30, to ease fund transfers.

** The China Development Bank has granted a 2 billion yuan ($290 million) emergency loan to Wuhan.

** Global equity markets rebounded as investors took in positive economic data from Europe and worried less about the potential economic toll of the outbreak. [MKTS/GLOB]

** Some experts believe the virus is not as dangerous as the 2002-03 Severe Acute Respiratory Syndrome (SARS) that killed nearly 800 people, and Middle East Respiratory Syndrome (MERS), which has killed more than 700 people since 2012.