Geographic Differences in U.S. COVID-19 Cases and Deaths, February–April 2020

This page summarizes a CDC snapshot of the COVID-19 pandemic in the United States as of April 7, 2020.

Community transmission of COVID-19 was first detected in the United States in February 2020, and by mid-March every state, the District of Columbia, New York City and four U.S. territories had reported cases. CDC's COVID-19 Response Team examined laboratory-confirmed cases and deaths reported from February 12 to April 7 by each state, territory and freely associated state, D.C. and New York City (counted separately from the rest of New York State), to show how unevenly the pandemic was unfolding.

The national picture on April 7

• 395,926 cases and 12,757 deaths had been reported.
• Cumulative incidence was 119.6 cases per 100,000 people.
• Doubling time for cases was about 6.5 days nationally.
• Over the previous week (March 31–April 7), incidence rose by 63.4 cases per 100,000.

Where the cases were

Two-thirds of all cases (66.7%) came from eight jurisdictions: New York City (76,876), the rest of New York State (61,897), New Jersey (44,416), Michigan (18,970), Louisiana (16,284), California (15,865), Massachusetts (15,202) and Pennsylvania (14,559).

CDC map: reported COVID-19 cases by jurisdiction, February 12–April 7, 2020.

In the continental United States, cumulative incidence ranged from 20.6 per 100,000 in Minnesota to 915.3 in New York City. Nine jurisdictions were above the national rate: New York City, New York State (555.5), New Jersey (498.6), Louisiana (349.4), Massachusetts (220.3), Connecticut (217.8), Michigan (189.8), D.C. (172.4) and Rhode Island (133.7).

Among the ten jurisdictions with the most cases, doubling times ranged from 5.5 days in Louisiana to 8.0 days in New York City. The weekly increase in incidence ranged from 8.3 per 100,000 in Minnesota to 418.0 in New York City, and exceeded the national increase in 11 jurisdictions.

Deaths

By April 7, 55 of the 56 jurisdictions reporting cases had reported at least one death, but about half of all deaths (52.7%) came from New York City (4,111), New York State (1,378) and New Jersey (1,232). Michigan, Louisiana, Washington, Illinois, California, Massachusetts and Georgia each reported 300 or more. Case-fatality ratios ranged from 0.7% in Utah to 5.7% in Kentucky.

Why places differed

• Timing of arrival. The first U.S. cases were travelers from China and their household contacts. The first cases with no known travel or contact appeared in California, Oregon and Washington in the third week of February, and community transmission was not widely reported elsewhere until early March.
• Population density. COVID-19 spreads mainly through respiratory droplets, and dense urban areas such as New York City and D.C. had incidence above the national average. Louisiana, whose population swelled with Mardi Gras visitors in mid-February — before canceling mass gatherings was common — had higher incidence and faster growth than other Southern states.
• Mitigation. School and workplace closures, canceled gatherings and shelter-in-place orders were adopted at different times, and they work best when put in place before transmission is widespread.
• Testing. New York State, outside New York City, had given 4.9 tests per 1,000 people by late March, against a national average of 1.6, which likely found more cases. Places that expanded testing later could expect their counts to rise.
• Who was infected. Deaths depend on whether the virus reached people at high risk of severe illness. In Washington, rapid spread in nursing and long-term care facilities contributed to 394 deaths among 8,682 cases (4.5%). Higher case-fatality ratios may also reflect places where testing was limited to the sickest patients.

Limitations

• Cases and deaths were likely undercounted, through incomplete detection, reporting delays, and deaths among people never diagnosed.
• How much was missed varied by jurisdiction and may account for much of the geographic variation.
• State-level figures may not be directly comparable, and they can hide local hot spots and the effects of local mitigation.

The authors concluded that tracking cases and changing incidence within each jurisdiction was critical for decisions about social distancing and about where to direct health care resources.

Sources

• CDC COVID-19 Response Team, "Geographic Differences in COVID-19 Cases, Deaths, and Incidence — United States, February 12–April 7, 2020," Morbidity and Mortality Weekly Report, CDC: https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e4.htm