-The World Health Organization's chief scientist, Dr. Soumya Swaminathan, has urged people to be cautious with their behavior even after receiving a COVID-19 vaccine.

-Swaminathan told a Monday briefing there was not yet enough evidence from vaccine trials "to be confident that it's going to prevent people from actually getting the infection and therefore being able to pass it on."

-She added that at least for now, even people who had received the vaccine should still quarantine when traveling to countries with lower coronavirus transmission rates.

-Vaccine researchers in the US are trying to determine whether vaccines can stop the virus from spreading or are effective only at preventing symptomatic cases of COVID-19.

The World Health Organization is urging even people who have received a coronavirus vaccine to quarantine when they travel because there is not yet evidence that vaccines prevent people from transmitting the virus.

WHO's chief scientist, Dr. Soumya Swaminathan, noted on Monday that the agency had not established whether the COVID-19 vaccines being administered across the US and in Europe prevented people from getting the virus and passing it to others.