A coronavirus vaccine developed in China has been proven effective in monkeys.
The vaccine made by a Beijing-based biotech company put a crippled virus into an animal's body, forcing its immune system to produce antibodies.
The vaccine has been undergoing human tests in China since mid-April.
China has classified all the country's counties as low-risk for the novel coronavirus disease.
The move comes as no domestic cases have been reported in the Chinese mainland for four consecutive days, and no new deaths for 22 consecutive days.
However, the health authorities are still warning of "a lot of uncertainties" of the epidemic situation.
The Nature magazine says China reduced the COVID-19 infections by 67 fold.
The article says if China did nothing to contain the novel coronavirus outbreak, there could have been more than seven million COVID-19 patients in the country by late February.
The study also suggests social distancing can greatly help reducing cases after travel restrictions are lifted.
Russia has reported a record of some 11-thousand new confirmed cases of COVID-19 over the past 24 hours.
This takes the total confirmed cases to nearly 180,000.
Moscow, the country's worst-hit region, confirmed over 6,700 new cases in one day.
It is being reported that medical examiners in Chicago are planning to probe deaths involving heart attacks and pneumonia for evidence of COVID-19 as far back as November.
Chicago reported its first known death on March 16.
It comes as a mayor in New Jersey claimed he was infected by the virus in November, about two months before the first confirmed case in the United States.
Foreign Ministry Spokesperson Hua Chunying says China has decided to join the international collaboration initiative launched by the World Health Organization to combat COVID-19.
She says that China firmly supports the WHO's leading role in global anti-pandemic cooperation, and will contribute in the research and production of medical products for COVID-19.
"Viruses know no borders. All peoples of the world deserve equal access to vaccines and medicines. Since the outbreak, China has shared the genetic sequence of the novel coronavirus with other countries in a timely manner, built platforms to share data and scientific research results, and actively carried out international cooperation on drug and vaccine research and development."
Last month, the WHO launched an international collaboration to accelerate the development, production and equitable distribution of vaccines, diagnostics, and therapeutics for COVID-19.
The head of the World Health Organization has urged countries lifting coronavirus restrictions to carefully manage the transition to avoid returning to lockdown.
Director-General Tedros Adhanom Ghebreyesus addressed the steps needed before countries lift measures put in place to curb the spread of the virus.
"The risk of returning to lockdown remains very real if countries do not manage the transition extremely carefully and in a phased approach."
The WHO chief stressed the need for more investment in health systems to save lives later.
He points out that the coronavirus crisis has exacerbated existing inequalities in many countries.
China's exports of goods rebounded last month, adding to signs that the country's foreign trade is stabilizing amid further containment of COVID-19.
Exports rose 8.2 percent year on year, compared with a drop of 11.4-percent in the first quarter.
Meanwhile, imports fell 10.2 percent last month.
In the first four months, foreign trade of goods totaled 9 trillion yuan, down 4.9 percent compared with the same period of last year.
China's courier sector saw an almost 40-percent increase in its business volume during the May Day holiday.
The State Post Bureau says the booming online sales of food, daily necessities and electronic devices has stimulated small-and medium-sized enterprises to quick work resumption.
Online sales of agricultural products has also maintained fast growth thanks to sufficient supply and demand.