World Health Organisation chief Tedros Adhanom Ghebreyesus has said he will self-quarantine after being identified as a contact of a person who tested positive for Covid-19.

Dr Tedros, 55, tweeted late on Sunday that he was “well and without symptoms”, but will self-quarantine in “coming days, in line with WHO protocols, and work from home”.

His agency followed that up on Monday with its own tweet apparently aimed to dispel misinformation about his decision, writing: “Contrary to some incorrect reports, @DrTedros hasn’t tested positive for #COVID19.”

The agency suggested later that Dr Tedros had not been tested and was not required to undergo a test under its current protocols. Dr Tedros and the WHO did not identify the contact who had tested positive.

Speaking at a regular WHO briefing, Maria Van Kerkhove, technical lead for the Covid-19 pandemic, said there had been no transmission of the virus at the agency’s main site in Geneva — a city like others across Europe that has faced a spike in cases in recent days, prompting new lockdown measures by local authorities.

“We haven’t had any transmission take place on the premises, and we have no clusters on the premises,” she said. “But it is something that we’re monitoring every day.”

Mike Ryan, the WHO’s emergencies chief, said its “current protocols” do not require Dr Tedros to be tested for the virus, and said “his testing will depend on the arrival of symptoms or otherwise, and he may be tested in the days to come”.

The WHO has tallied “a number of cases” since the outbreak swept the globe earlier this year, Dr Ryan said, adding that “most cases have been acquired at community level, very few within the building here”.

Asked about the contradiction about whether any transmission had occurred on-site, WHO spokeswoman Margaret Harris said the public position from the agency was that there has been none at headquarters.

Dr Tedros’s self-quarantine highlights the risks and challenges many businesses and organisations face in keeping Covid-19 at bay, and a UN agency office teeming with medical experts, renowned scientists and specialists on viruses is no exception.

Dr Ryan noted that staff who enter the building undergo temperature checks on arrival, are asked to self-declare about their health status every day, and can benefit from “an immediate response mechanism” if they become ill at home or the office.

“This is not a zero-risk situation. We’ve said it again and again,” he said. “There is… no environment right now in the world without risk.”

The WHO director-general and his team have been at the forefront of the global response to the coronavirus pandemic, which has infected at least 46.5 million people and led to more than 1.2 million deaths, according to a count of confirmed cases by Johns Hopkins University.