In nearly half of U.S. states— 22 out of 50— coronavirus cases are rising. This is particularly concerning following the Labor Day holiday weekend, which Americans typically celebrate with parties and family gatherings, inviting easy transmission of the virus.

Johns Hopkins University warned in a report last month that “Unlike many countries in the world, the United States is not currently on course to get control of this epidemic.”

Since February, at least 186,000 Americans are confirmed to have died from COVID-19, though the true case and death counts are probably much higher as testing remains scarce in many places.

In April, the U.S. coronavirus death toll peaked at more than 2,000 deaths per day but decreased to 456 in early July. By August the rate again increased to an average of more than 1,000 deaths per day.

South Dakota has seen the most significant percentage increase in the country over the past two weeks, with 3,700 reports of new cases (+126%). Cases are also increasing quickly in Iowa and North Dakota, which added 13,600 and 3,600 over the same period, respectively.

However, in the most populous states of California, Florida, and Texas, new infections have decreased over the same period.

Dr. Anthony Fauci has warned that the outbreak could dramatically worsen in the coming months as the cold weather sets in and more time spent inside increases the risk of transmission.