BEIJING — A coronavirus vaccine candidate China is developing may not be ready for sale until at least 2021, as researchers struggle to move into large-scale human trials in the country because of a lack of new infections, a senior company executive said. More than 10 experimental vaccines are being tested in humans globally as scientists race to protect against the novel coronavirus that has killed more than 450,000 people. But none of them has yet passed late-stage phase 3 trials that require thousands of participants to determine a vaccine candidate's effectiveness. China, where the virus first originated last year, saw less than 10 new local cases reported daily on average in May, making it less favorable for a late-stage clinical trial.

Source: International New York Times June 19, 2020 13:30 UTC