From the first cases in China in late 2019 to the declaration Monday by the WHO that it remains an international emergency, here are key moments in the Covid-19 pandemic.

Dec 2019: emerges in China

On December 31, 2019, the World Health Organization (WHO) is alerted to a cluster of pneumonia cases "of unknown cause" in the central Chinese city of Wuhan.

A week later, a new coronavirus is identified. China confirms on January 11 its first death in Wuhan from an illness which will be named Covid-19.

On January 23, Wuhan is placed under quarantine.

March 2020: 'pandemic'

The virus nevertheless rapidly spreads. By March 6, more than 100,000 cases have been recorded around the world.

On March 11, the WHO says Covid-19 is a pandemic.

March 2020: Europe in lockdown

Italy, the first European country to be hard hit, on March 12 imposes a lockdown in the north which it then extends nationwide.

Spain (March 14) and France (March 17) place their populations under lockdown. Germany and Britain say people should avoid all social contact. The 27-nation European Union closes its external borders.

April 2020: Half world confined

Lockdown measures are enforced all around the world.

On April 2, more than 3.9 billion people -- half of the world's population -- are forced or called on to stay at home, according to an AFP count. The threshold of one million cases is exceeded.

World stock markets crash and whole sectors of the world economy are brought to a halt. Airlines, aircraft and car manufacturers, tourism and department stores suffer and lay off staff. Governments and central banks announce massive support measures.

June 2020: US, Brazil in mourning

The virus takes off in the United States and Brazil, with the two giants overtaking Europe to register the biggest tolls.

Brazil's President Jair Bolsonaro dismisses Covid as a "little flu", while US counterpart Donald Trump says the virus will go away naturally.

Their management of the pandemic is heavily criticised.

August 2020: anti-masks, anti-vax, anti-pass

In mid-2020, amid a new upsurge, several European countries make mask wearing compulsory on public transport, in schools and shops and on the street, sparking sometimes virulent anti-mask demonstrations.

A year later, opposition turns to anti-Covid vaccines, and the health passes people in some countries are obliged to show to take trains and planes or use public amenities.

Dec 2020: vaccines in record time

Vaccines are rolled out in record time, with the first jabs given in late 2020 in the United States and Europe.

Campaigns start out slowly before picking up speed in 2021 in western countries.

But access to vaccines remains very unequal, with only 24 percent of the population vaccinated in Africa against 64 percent at world level, according to the WHO.

Jan 2021: origin probe

A WHO team of international experts visits Wuhan in January 2021 to investigate the origins of the virus.

Beijing then baulks at calls for further investigation on the ground.

In July 2022, the WHO says "all hypotheses remain on the table," as studies conclude that Covid-19 first emerged at an animal market in Wuhan.

April 2021: Delta ravages India

The highly contagious Delta variant causes huge loss of life in April and May in India, which registers the world's third highest death toll. It then spreads quickly to the rest of the world, particularly Russia.

In late November, the heavily mutated Omicron strain -- the most transmissible to date -- emerges in South Africa, prompting global panic. It spreads around the world in early 2022 sparking record infections but with less severe symptoms.

Dec 2022: China ends zero-Covid

Despite its relatively low death toll, China counts the cost of the zero-Covid policy of President Xi Jinping at a time when other countries have decided they can live with the virus.

Public anger boils over against the prolonged restrictions, including lockdowns at the first hint of infections, leading to the largest nationwide protests in decades.

In response, Chinese authorities decide on December 7 to radically ease the restrictions.

A surge in infections swiftly follows, along with shortages of medicine, while hospitals and crematoriums across the country overflow with Covid patients and victims.

Jan 2023: still an emergency

Three years to the day after the WHO sounded the highest level of global alert over Covid-19, it says on January 30 that the pandemic remains an international emergency.

WHO chief Tedros Adhanom Ghebreyesus says the weekly death rate has been rising since the start of December, while the lifting of restrictions in China has led to a deaths spike.

Globally, 6.8 million deaths from Covid-19 have been reported to the WHO.