The World Health Organization (WHO) said the United Nations Health Agency would not recommend any COVID-19 vaccine before it is proved safe and effective, even as Russia and China have started using their experimental vaccines before large studies have finished and other countries have proposed streamlining authorization procedures.

WHO Director-General Tedros Adhanom Ghebreyesus said newly developed Ebola vaccines helped end the recent Ebola outbreak in Congo, noting that stopping the deadly virus was complicated by the dozens of armed groups operating in the region.

He also appealed to people opposed to vaccination to do their own research.

Last week, Britain said it was preparing to revise its laws so that any effective coronavirus vaccine could be used before it was fully licensed.

Russia became the first country in the world to approve a COVID-19 vaccine in August after licensing a shot that had only been tested in several dozen people.

On Friday, Russian scientists published data from early studies suggesting their vaccine was safe and prompted an antibody response, but the results were limited, and experts said the shot had not yet proven to work.