Tracking The Pandemic: How Quickly Is The Coronavirus Spreading State By State?
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Since the first coronavirus case was confirmed in the United States on Jan. 21, over a half-million people in the U.S. have confirmed cases of COVID-19. On April 12, the U.S. became the nation with the most deaths globally, but there are early signs that the U.S. case and death counts may be leveling off, as the growth of new cases and deaths plateaus. The pattern isn't consistent across the country, as new hot spots emerge and others subside.
To see how quickly your state's case count is growing, .
Click here to see a global map of confirmed cases and deaths.
In response to mounting cases, state and federal authorities have emphasized a social distancing strategy, widely seen as the best available means to slow the spread of the virus. Most states have put in place measures such as closing schools and nonessential businesses and ordering citizens to stay home as much as possible.
It's not clear how long such measures need to be in place to see a lasting effect. In Wuhan, the city in China where the virus originated, a strictly enforced lockdown and widespread testing have slowed the outbreak dramatically, enough to bring an end to the 76-day lockdown.
A large portion of U.S. cases are centered on New York City. Since March 20, New York state, Connecticut and New Jersey have accounted for around 50% of all U.S. cases. As of April 9, nearly 60% of all deaths from COVID-19 have been in these three states. While New York state appears to be reaching a plateau, as seen below, it notched between 8,000 and 10,000 new cases each day between March 31 and April 12.
To understand how one state's outbreak compares with another's, it's helpful to look at not just the daily counts but the rate of change day over day. In the following chart, we display cases on a logarithmic scale, meaning that every axis line is 10 times greater than the previous one. This type of scale emphasizes the rate of change.
When case counts grow very quickly, a state's curve trends sharply upward, as New York's does over the first 15 days past 100 cases. Generally, this is evidence of unbridled community transmission of the disease. As new cases slow, the curve bends toward horizontal, showing that the state's outbreak may be leveling off. This doesn't mean the number of cases has stopped growing, but the rate of growth has slowed, which could signify that social distancing measures are having an effect.
In some areas, there are signs of hope. The areas with the earliest outbreaks — such as California and Washington — seem to be having success at suppressing the disease. The outlook in Washington has improved to the point that the state has returned unused Army hospital beds it had received in preparation for a peak in cases.
Elsewhere, limited access to testing may make the number of cases look smaller than it really is. As testing becomes more readily available, we are likely to see the number of confirmed cases continue to grow, even if not at the pace previously seen.
The data used here are compiled by the Center for Systems Science and Engineering at Johns Hopkins University from several sources, including the Centers for Disease Control and Prevention; the World Health Organization; national, state and local government health departments; ; and local media reports. The JHU team automates its data uploads and regularly checks them for anomalies. State-by-state testing and hospitalization data are still being assessed for reliability. State-by-state recovery data are unavailable at this time. There may be discrepancies between what you see here and what you see on your local health department's website.
Stephanie Adeline, Alyson Hurt, Connie Hanzhang Jin, Ruth Talbot and Thomas Wilburn contributed to this story.
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