FILE PHOTO: A Gilead Sciences, Inc. logo is seen outside the company headquarters in Foster City, California, U.S. May 1, 2018. REUTERS/Stephen Lam

(Reuters) - Gilead Sciences Inc GILD.O said on Friday it provided its experimental Ebola therapy for use in a small number of patients with the coronavirus that has killed over 200 so far in China and is working with the country's authorities to set up a study.

The announcement comes a day after the World Health Organization declared the coronavirus epidemic a public health emergency of international concern.

The company said it was also expediting laboratory testing of the antiviral drug, remdesivir, against samples of the new coronavirus, which has infected nearly 10,000 globally.

Johnson & Johnson JNJ.N on Wednesday joined a growing list of drugmakers to begin work on developing a vaccine for the virus.

Co-Diagnostics Inc CODX.O said on Friday initial verification of its screening test designed to identify the presence of the coronavirus was successful. Shares of the company closed up 20.7%.

Last week, director of the U.S. National Institute of Allergy and Infectious Diseases, Dr. Anthony Fauci, told Reuters his agency was working with Gilead to test remdesivir.

The drug had previously been tested in patients with Ebola but was found to be ineffective. Gilead told Reuters last week that the drug was shown to be active in animals with Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome, which are closely related to the current virus.

As health authorities race to contain the outbreak, U.S. health officials on Friday said nearly 200 Americans were placed under quarantine at a U.S. air base in California after being evacuated from Wuhan, China.