The World Health Organizations outgoing chief
In her final address to WHO's member states, Chan acknowledged that mistakes had been made during her decade at the helm, but stressed that while "we falter sometimes, ... we never give up."
"The world is better prepared, but not nearly well enough," she told the some 4,000 delegates gathered from WHO's 194 member countries for its annual assembly in Geneva.
Chan, whose successor will be elected Tuesday, presented a range of achievements she insisted dispelled "the frequent criticism that WHO has lost its relevance".
She had reason to be on the defensive: During her tenure, WHO faced crushing criticism for its handling of several health emergencies, but none more than the west Africa Ebola epidemic that killed more than 11,300 people between late 2013 and early 2016.
"The outbreak took everyone, including WHO, by surprise," Chan said.
"WHO was too slow to recognise that the virus, during its first appearance in West Africa, would behave very differently than during past outbreaks in central Africa."
But she pointed to a wide range of reforms initiated while the crisis roared, saying the UN health agency had "made quick course corrections", brought the outbreak "under control, and gave the world its first Ebola vaccine".
'History will judge'
"I saw it as my duty to do everything possible to ensure that a tragedy on this scale will not happen again," Chan told the delegates, adding that "history will judge" if she had succeeded.
Among WHO's achievements over the past decade, Chan highlighted efforts to develop "affordable vaccines for priority pathogens... as a head-start for responding to the next inevitable outbreak."
She also pointed to significant progress in the fight against HIV, tuberculosis and malaria, as well as against a wide range of long neglected tropical diseases.
Many country representatives took the floor to hail Chan's time at the helm.
"You have pursued essential reforms that will make WHO more transparent, more effective and more accountable," US Health Secretary Tom Price said.
But he, like many of his colleagues, said the next WHO head must continue overhauling the agency, "taking a clear-eyed view of what needs to change".
All three candidates to replace Chan have vowed to push ahead with reforms.
The finalists include former Pakistani health minister Sania Nishtar and WHO insider David Nabarro, a British doctor and diplomat who has spent two decades inside the UN system.
Ethiopia's former foreign and health minister Tedros Adhanom is also on the list, aiming to become the first African to hold the post.
He enjoys strong backing from Africa, but on Monday around 100 demonstrators gathered outside UN headquarters in Geneva to protest at his candidacy, according to the Swiss ATS news agency.
One briefly delayed Chan's speech inside the assembly hall, shouting "No Tedros at WHO".
The demonstrators charged that he downplayed cholera outbreaks in Ethiopia with disastrous consequences -- something he has denied.
The opening of the 70th World Health Assembly was also marred by the exclusion of Taiwan, which had been permitted to participate as an observer for the past seven years but did not receive an invitation this year under pressure from China.
Earlier Monday, 11 countries urged the assembly to debate whether to offer Taiwan permanent observer status.
But China, which sees the self-governing island as a renegade province awaiting reunification, insisted it alone should decide whether Taiwan could access the meeting, and the motion was rejected without a vote.
"Taiwan is part of China. Questions regarding Taiwan are China's internal affairs," the Chinese representative at the meeting said.
In an interview with AFP on Sunday, Taiwanese Health Minister Chen Shih-chung said he was "very, very disappointed" at Taipei's exclusion.
US Secretary Price also voiced disappointment Monday, insisting that Washington "remains committed that Taiwan should not be excluded from WHO".