From a Pneumonia Cluster to a Pandemic
On 31 December 2019 health authorities in Wuhan, China, published a notice about cases of viral pneumonia, many of them linked to the Huanan Seafood Wholesale Market. Ten days later the first genome of the new coronavirus, SARS-CoV-2, was made public, and on 13 January 2020 Thailand confirmed the first case outside China. Within months it had reached almost every country, and over the next three years new variants swept the world one after another.
This map tells that story in two parts. Part 1 (December 2019 to August 2020) shows where confirmed cases were rising, by country and, in China, Italy and the United States, by province, region or state. Part 2 (October 2020 to May 2023) shows which variant dominated each country's sequenced samples.
Part 1: The First Wave Crosses the World
The first weeks belong to China. Wuhan, a city of more than 11 million, was locked down on 23 January 2020, and Hubei fills with colour while the first circles appear abroad: the United States announced its first case, in Washington state, on 21 January, and France confirmed Europe's first cases on 24 January. On 30 January the WHO declared a Public Health Emergency of International Concern, its highest level of alert.
February brought the first large clusters outside China. The Diamond Princess cruise ship was quarantined at Yokohama, where 712 of the 3,711 people aboard were eventually infected. In South Korea a church cluster in Daegu began a rapid rise from 18 February; Iran reported its first cases in Qom on 19 February; and on 21 February clusters were found in Lombardy and Veneto, where Italy quarantined Codogno and ten other municipalities. On 9 March Italy locked down the whole country, and on 11 March the WHO said COVID-19 could be characterised as a pandemic.
Lockdowns and the Move West
By mid-March Europe was the epicentre. Spain declared a state of alarm on 14 March, the United Kingdom ordered a national lockdown on 23 March and India began a 21-day national lockdown on 25 March. In early April New York was the centre of the US outbreak, while Wuhan's lockdown ended on 8 April after 76 days. From May the map's reds move to the Americas: Brazil, Peru and the US Sun Belt, then India and South Africa during the northern summer. Part 1 ends on 28 August 2020, as Europe's second wave begins; a month later the global tally of reported deaths passed one million.
Part 2: The Age of Variants
From October 2020 the map switches from case rates to variants, and most countries still carry earlier lineages. On 14 December the UK announced a faster-spreading variant first identified in Kent, later named Alpha; South Africa announced the lineage later named Beta on 18 December; and in January 2021 a variant from Manaus, later named Gamma, was detected in travellers arriving in Japan. By May 2021 Alpha leads in more countries than any other variant, while Gamma dominates Brazil and many of its neighbours. Vaccination had begun: the first dose outside trials was given in Coventry on 8 December 2020.
In April 2021 Delta erupted in India, which on 7 May reported more than 414,000 new cases in a day, a world record at the time. On 31 May the WHO introduced Greek-letter names for the variants. By July 2021 Delta led in most countries, and by October 2021 it was the dominant variant almost everywhere the map has enough sequences.
Omicron and Its Descendants
South Africa reported a new lineage, B.1.1.529, to the WHO on 24 November 2021; two days later the WHO named it Omicron. By 5 January 2022 Omicron BA.1 had replaced Delta in most countries, and on 3 January the US reported more than one million new cases in a single day. Omicron then came in waves of its own: BA.2 rose in spring 2022, BA.4 and BA.5 dominated almost everywhere by August, and in early 2023 XBB lineages took over. China eased its zero-COVID policy on 7 December 2022. The map ends on 5 May 2023, when the WHO ended the COVID-19 emergency.
How to Read the Map
In Part 1 each country, Chinese province, Italian region or US state is coloured by new confirmed cases per million people in the 14 days before each date: brown for under 10, amber for 10 to 100, orange for 100 to 500 and red for 500 or more. A country first appears as a circle around the city of its first confirmed case. In Part 2 colours stand for the variant that made up most of a country's sequenced samples in the previous four weeks: grey for earlier lineages, blue for Alpha, green for Beta, lime for Gamma, red for Delta, gold for Omicron BA.1, pink for BA.2, purple for BA.4 and BA.5 (including BQ.1), cyan for XBB and lilac for other variants such as Epsilon, Iota, Lambda and Mu. Countries with too few sequences stay uncoloured. The bar counts reported deaths worldwide: about 6.9 million by 5 May 2023.
Confirmed cases depend on testing and undercount real infections, especially early in 2020 and in countries that tested little.
How the Map Was Made
Case and death counts come from the WHO COVID-19 dashboard and Our World in Data, with Johns Hopkins University CSSE data for China and Taiwan, The New York Times for US states and the Italian Protezione Civile for Italy's regions. Variant shares come from CoVariants.org, which is based on sequences shared through GISAID. First cases and events come from Wikipedia.
Chronological Timeline
- 31 December 2019 — Wuhan reports a cluster of viral pneumonia
- 13 January 2020 — Thailand confirms the first case outside China
- 23 January 2020 — Wuhan is locked down
- 30 January 2020 — WHO declares a Public Health Emergency of International Concern
- 11 March 2020 — WHO characterises COVID-19 as a pandemic
- 23–25 March 2020 — National lockdowns in the United Kingdom and India
- 28 September 2020 — Reported deaths worldwide pass one million
- 8 December 2020 — First vaccination outside trials, in Coventry
- 14 December 2020 — Alpha variant announced in the UK
- May 2021 — Delta wave in India; WHO introduces Greek-letter variant names
- 26 November 2021 — WHO names Omicron
- January 2022 — Omicron BA.1 dominant in most countries
- Spring–summer 2022 — BA.2 rises, then BA.4 and BA.5 take over
- Early 2023 — XBB lineages spread
- 5 May 2023 — WHO ends the COVID-19 emergency
Explore the pandemic week by week in the interactive map: pause on any date, click a country or marker for details, or embed the map on your own site. You can also export it as an animated GIF for presentations, lessons and social media.
Explore the full interactive map →