Coronavirus map: Tracking the spread in the US and around the world

By Friday, the novel coronavirus outbreak in the United States had grown to at least 270,473 cases in all 50 states, the District of Columbia and Puerto Rico. There are outbreak clusters in New York, Washington State and California, according to Johns Hopkins University, which is tracking reports and confirming them with local health departments.

The number of cases in the U.S. and worldwide is the subject of some debate, as testing has been rolled out unevenly and the criteria for diagnosis (through clinical means or a lab test) has varied from country to country.

For more information on COVID-19 cases in your state, check your state's health department website, listed below. The U.S. Centers for Disease Control and Prevention maintains nationwide statistics, but they are not updated as frequently. Information from Johns Hopkins University is not independently verified by ABC News.

The growing number of lab-confirmed cases in the U.S. at this point still pales in comparison to the seasonal flu, which kills an estimated 12,000 to 61,000 people per year and affects between 9 million and 45 million people in the country, according to the CDC.

Still, experts warn that the COVID-19 shouldn't be downplayed or compared to a bad case of the flu. Instead, the respiratory disease is more akin to severe pneumonia, and in serious cases, patients experiencing difficulty breathing have been hospitalized and put on ventilators.

What is unknown is how deadly coronavirus, which has no treatment at this point, is compared to the flu or how serious its effects are for those who are sickened but do not die.

Of those cases in the U.S. (pictured above), at least 48 were diagnosed in individuals who were repatriated to the United States on government charter flights from Wuhan, China, and from the Diamond Princess cruise ship. But many others are cases of unknown origin, or community spread, where there is no known nexus to travel.

Tracking Novel Coronavirus Worldwide

Meanwhile, the virus, officially known as COVID-19, has spread to dozens of countries in regions around the world.

The novel coronavirus outbreak began in Wuhan, China, in late December, and has since sickened at least 1 million people worldwide, including at least 270,473 in the United States, and killed tens of thousands, primarily in mainland China, Italy, Spain, France, Iran and the United States, according to data from Johns Hopkins. A least 225,438 people globally have already recovered, JHU said.