LONDON — A key researcher at the University of Oxford says scientists expect to report results from the late-stage trials of their COVID-19 vaccine by Christmas.

Dr. Andrew Pollard, an expert in pediatric infection and immunity at Oxford, said Thursday that research was slowed by low infection rates over the summer but the Phase III trials are now accumulating the data needed to report results.

He told the BBC, “I think we’re getting close, and it’s definitely going to be before Christmas based on the progress.”

Pollard discussed progress in the late-stage trials as Oxford released a study based on earlier research that found the vaccine was well tolerated and produced a strong immune response in people over age 70. Pollard said this is important because vaccines often don’t work as well in older people.

BEIJING — Chinese President Xi Jinping is calling for closer international cooperation on making a vaccine for the coronavirus available.

Xi spoke Thursday in an address delivered via video at an event at the Asia-Pacific Economic Cooperation forum.

Xi said: “To beat the virus and promote the global recovery, the international community must close ranks and jointly respond to the crisis and meet the tests.”

He said cooperation would include closer coordination on policies for development and distribution of a vaccine.

Chinese companies Sinovac and Sinopharm are in the late stages of testing vaccines, putting them among nearly a dozen companies at or near that level of development. That has introduced both commercial and political competition among countries and companies to be the first to offer a solution to the pandemic.