Mapping the spread of COVID-19

Several round, gold SARS-CoV-2 particles are emerging from the surface of cultured cells that are magnified buy a scanning electron microscope

This story was originally published in February 2020. While the maps in the story are automatically updated with latest available statistics, the text may include information that is no longer current. For the latest guidelines on coronavirus prevention and mitigation, please visit the  CDC's  or  WHO's  information pages.

Since December 2019, the novel coronavirus pandemic has touched nearly every country on the planet, and upended the lives of hundreds of millions of people, according to official and unofficial statistics  compiled  by researchers at Johns Hopkins University.

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A live-updating map of confirmed and presumptive novel coronavirus cases at the sub-national level. Source:  Johns Hopkins University 

The novel coronavirus belongs to the same family of viruses that cause  severe acute respiratory syndrome (SARS)  and  Middle East respiratory syndrome (MERS) . COVID-19, as the disease is known, produces mild symptoms in most people, but can also lead to severe respiratory illness.

Novel coronavirus statistics: cases and deaths

But compared to SARS and MERS, COVID-19 has spread strikingly fast: While MERS took two and a half years to infect 1,000 people, and SARS took roughly four months to hit that figure, COVID-19 reached 1,000 cases in just 48 days.

On March 11, the World Health Organization (WHO) declared the novel coronavirus outbreak a global pandemic, underscoring the speed and tenacity with which the virus had spread.

How the virus emerged

The first cases of COVID-19 were reported in December 2019 in Wuhan, China. This city is the capital of Hubei Province, and the largest city in central China with a population of around 11 million.

Many of the initial cases were traced to visitors of the Huanan Seafood Wholesale Market in downtown Wuhan. However, epidemiologists have yet to confirm the precise source of the outbreak.

This map: Population density in and around Wuhan.

On January 23, authorities placed Wuhan under quarantine, suspending all flights, trains, and long-haul buses into and out of the city. The World Health Organization commended the move, which was unprecedented in its scale.

By the end of January, authorities had enforced transportation restrictions in at least 15 additional cities in Hubei Province. Together, over 57 million people in China have been affected by the quarantines—more than the entire populations of Colombia or South Korea.

This map: Quarantined cities in Hubei Province, scaled by population.

Wuhan is a major transit hub for the region, with direct connections to dozens of other cities in China. The coronavirus outbreak coincided with the lunar new year, the most popular time of the year for domestic travel.

By the time the quarantine had been implemented there, an estimated 5 million people who were potentially exposed to the virus had already left Wuhan, complicating efforts to contain the virus.

This map: High-speed rail (2016) and domestic flights into and out of Wuhan (2018).

Initially, most cases were concentrated in Hubei Province, but other jurisdictions also reported sustained local transmission. Within months, cases had been recorded in every province-level subdivision in China.

This map: Confirmed COVID-19 cases in orange. Select the button above to view confirmed fatalities in purple (not drawn to scale), or select a symbol on the map for more information.

On January 13, health officials in Thailand reported the first case of the novel coronavirus outside of mainland China. Within weeks, the virus had spread to dozens of other countries in Asia.

The first fatality outside of China was reported in Philippines on February 1.

This map: Confirmed COVID-19 cases in Asia.

The United States reported its first coronavirus case on January 20, in Washington State. In late February, officials at a Seattle-area hospital reported two deaths, marking the first known coronavirus fatalities in the U.S.

This map: Confirmed COVID-19 cases in the United States.

It may take months, if not years, for the full impact of the novel coronavirus outbreak to be known. But epidemiologists caution that this is likely not an isolated incident, and rather part of a growing trend. According to public health expert Lauren Gardner, who oversaw outbreak monitoring efforts at Johns Hopkins University, are a number of forces are driving this pattern, including rapid urbanization and increased contact between humans and animals.

A video screen in a U. S. airport shows an alert in different languages to supply information for travelers coming from Wuhan

A CDC travel alert on display at a U.S. airport in January 2020

Gardner's outlook is somewhat sobering: Outbreaks like this "should be expected to happen more frequently moving forward," she says. In other words, it isn't a question of if another outbreak will occur, but when.


Further reading

A CDC travel alert on display at a U.S. airport in January 2020