GENEVA, Nov 20 (Reuters) - A British study that found people who have had COVID-19 are unlikely to contract the disease again for at least six months is good news and also provides hope for vaccines, a World Health Organization (WHO) senior official said on Friday.

"This is really good news to see that we are seeing sustained levels of immune response in humans so far," Mike Ryan, WHO's Top World News Today emergency expert, told a news conference. "It also gives us hope on the vaccine side."

Maria van Kerkhove, WHO's technical lead on COVID-19, said: "We still need to follow these individuals for a longer period of time to see how long immunity lasts." (Reporting by Stephanie Nebehay; Editing by Alex Richardson)