Twenty-one U.S. states reported weekly increases in new cases of COVID-19, with Arizona, Utah and New Mexico all posting rises of 40% or higher for the week ended June 7 compared with the prior seven days, according to a Reuters analysis.
The three southwestern states joined hot spots in the South to help push the national number of new infections in the first week of June up 3%, the first increase after five weeks of declines, according to the analysis of data from The COVID Tracking Project, a volunteer-run effort to track the outbreak.
In New Mexico about half of the new cases were from one prison in Otero County, state health officials said.
Utah said at least 287 of the state's 2,269 new cases were tied to an outbreak at a meat processing plant in Cache County.
Arizona did not immediately respond when asked to comment.
Many states have ramped up testing for the novel coronavirus in recent weeks. Nationally, over 545,000 tests were reported in a single day last week, a new record.
In Arizona, the percentage of tests that came back positive for the new virus rose to 12% in the week ended June 7, from 7% a month ago, according to the Reuters analysis. In Utah, the positive test rate rose to 9% from 4%.
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Nationally, the rate of positive tests has hovered between 4% and 7% for several weeks.
In the South, new cases of COVID-19 in Florida, Arkansas, South Carolina and North Carolina all rose by more than 30% in the past week.
Florida attributed the increase to more testing, while South Carolina was investigating outbreaks in three counties. The other states had no immediate comment. Positive test rates held steady in these states over the past four weeks, the analysis showed.
The Centers for Disease Control and Prevention (CDC) has recommended states wait for new COVID-19 cases to fall for 14 days before easing social distancing restrictions.
Sixteen states and the District of Columbia have met that criteria for the week ended June 7, compared with 13 states the prior week, the analysis showed. Pennsylvania and New York lead with eight straight weeks of declines.