It took four weeks for WHO chief Tedros Adhanom Ghebreyesus to declare the virus circulating in Wuhan a Public Health Emergency of International Concern – the highest level of alarm under international health rules.
At that stage, on 30 January 2020, fewer than 100 people had been infected outside China, and no one had died.
The global health organisation's panel of expert advisers seemed unsure of the best course of action. There were conflicting messages on the effectiveness of face masks, at a time when there were very few suitable masks available anyway.
Wuhan was quarantined, and foreign nationals started leaving China. The WHO hesitated on advising governments to close borders and halt international flights.
By 6 March, more than 100,000 cases had been reported around the world.
'Threatening the whole of humanity'
It was only on 11 March 2020, after Tedros finally used the word "pandemic", that national governments began to wake up.
Incidentally, the word "pandemic" does not feature in the official international health alert system. As things stand, there is nothing more serious than the Public Health Emergency of International Concern, already declared on 30 January.
March 2020 saw the rapid spread of national lockdowns, with Spain (14 March) and France (17 March) ordering their populations to stay at home.
Germany and Britain said people should avoid all social contact. The then 28-nation European Union closed its external borders.
On 24 March, the Tokyo summer Olympics, scheduled for July, were postponed for a year. The following day the United Nations warned that the pandemic was "threatening the whole of humanity".
By early April, at least half the global population was confined. The global economy was at a virtual standstill. One million cases had been confirmed.
Tragic landmark of two million dead
On 7 June, the global death toll exceeded 400,000. By the end of September, there had been more than a million deaths. That number doubled in just four months, with two million dead by 15 January 2021.
January also saw the emergence of highly contagious variants of the virus in the UK, South Africa and Brazil.
PHOTOS: A violinist in Brazil is back to performing on the street to feed his son. It's one of many tales showing humankind’s indomitable spirit as the pandemic enters its second year. More on the pandemic's first year: https://t.co/OpCbgqkvku https://t.co/H6lUXarRbg
— The Associated Press (@AP) March 11, 2021
Vaccination campaigns got under way in December 2020, with the process hampered by mismanagement, misinformation, supply problems and public scepticism.
One year on, more than 300 million doses of vaccines have been administered around the world and some countries have begun to ease restrictions.
What lessons for World Health Assembly?
The annual World Health Assembly, the WHO's board of directors, is due to meet in May to review the organisation's handling of the crisis.
Some health specialists fear that no real changes will emerge. Dozens of expert panels met to assess the failures in the response to the Ebola outbreak in West Africa in 2014-2016.
“Less than 10 percent of the recommendations were followed up on,” says Joanne Liu, a former president of the French charity Médecins Sans Frontières.
“We have an amazing talent to outrage ourselves about a situation, but when it comes time to deliver any change, there is very little traction, and people go back to doing whatever they had done before.”
