A new coronavirus, later named SARS-CoV-2, was identified in the Chinese city of Wuhan at the end of 2019 and spread around the world within months. The disease it causes, COVID-19, prompted frequent comparisons with the Spanish flu of 1918–1920. Governments imposed lockdowns that at one point covered more than half the world's population, vaccines were developed in under a year, and the economic shock was the worst since the Great Depression. The World Health Organization (WHO) ended its global health emergency in May 2023.
Outbreak in Wuhan
The outbreak was detected in Wuhan, in the Chinese province of Hubei, in late 2019; molecular studies suggest the first infections probably occurred in October or November. Many early patients had connections to the city's Huanan Seafood Wholesale Market, where live animals were also on sale. Local doctors raised the alarm in late December, and several of them, including the ophthalmologist Li Wenliang, were detained by police in early January 2020 for "spreading false rumours". The WHO's China office was notified of a cluster of unexplained pneumonia cases on 31 December 2019. Chinese authorities identified the new virus on 7 January, its genome was published on 10 January, and the first confirmed death occurred in Wuhan on 9 January.
The question of origins
The origin of the virus has been the subject of intense debate. The prevailing scientific view is that it most likely passed to humans from bats, either directly or through another animal. The alternative suggestion that it escaped accidentally from a laboratory has also been put forward; as of 2021 it was regarded as lacking sufficient supporting evidence. In June 2025 a WHO scientific advisory group reported that the weight of available evidence pointed to spillover from animals.
Global spread
Helped by travel around the Chinese New Year, the virus spread quickly. The WHO declared a public health emergency of international concern on 30 January 2020 and described the outbreak as a pandemic on 11 March. Italy suffered the first major European outbreak and by 19 March had overtaken China in reported deaths; a week later the United States overtook both to record the most confirmed infections. Responses ranged from public information campaigns to strict lockdowns, and by early April about 3.9 billion people were living under some form of restriction. China pursued a "zero-COVID" policy of strict containment before it began lifting its toughest measures in December 2022.
Vaccines and variants
Vaccines were developed at unprecedented speed. Pfizer published trial results in November 2020, and on 2 December 2020 the United Kingdom became the first developed country to approve its vaccine. By August 2024 more than 5.6 billion people had received at least one dose. Meanwhile the virus evolved: the Alpha variant was reported in England in December 2020, Delta was first identified in India, and the highly infectious Omicron was detected in South Africa in November 2021.
The human toll
Counting deaths has proved difficult. More than 7 million deaths had been officially attributed to COVID-19 by 2026, but these figures depend on testing and reporting and are widely thought to understate the true toll. In May 2022 the WHO estimated that excess deaths up to the end of 2021 totalled 14.9 million, against 5.4 million reported COVID-19 deaths. Other estimates of total excess deaths, such as those by The Economist, range from about 18.5 to 35.2 million.
Wider effects
The pandemic closed schools and workplaces, disrupted supply chains, made remote working common and briefly reduced pollution. It also fuelled misinformation, political division and arguments over the balance between public health and individual rights, and drew attention to inequalities in health and access to vaccines. After the WHO ended the emergency on 5 May 2023, the disease continued to circulate, and in 2025 the World Health Assembly adopted a Pandemic Agreement prompted by weaknesses exposed in the global response.
On our maps
Our 2010 map, the most recent, shows the world as it stood a decade before the pandemic, including China, where the first outbreak was identified.