Confirmed coronavirus infections in the U.S. topped 6 million this week, and while case numbers nationally have recently trended downward, the positivity rate—the percentage of new COVID tests that are positive—in a majority of states is still worryingly high headed into the Labor Day weekend, according to a Fortune analysis of state data aggregated by the COVID Tracking Project.
The seven-day average positivity rate tops 10% in 13 states, including Alabama (24.5%), South Dakota (23.3%), North Dakota (18.9%), Iowa (17.8%), and Kansas (17.1%). The White House Coronavirus Task Force considers a positivity rate above 10% as one of the two factors that determine whether a state is a “red zone.” (The other is a case rate that is greater than 100 per 100,000 residents.) In general, these states have seen COVID infections spike with students returning to their college campuses.
The World Health Organization and other experts, meanwhile, consider a positivity rate of 5% as too high. (The WHO recommended governments not reopen until positivity rates were below that threshold for two weeks.) Another 21 U.S. states have experienced an average positivity rate between 5% and 10% for the past seven days. The CDC has suggested that it is safe to reopen schools when the positivity rate is below 5%.
Positivity rates are lowest in the Northeast. Vermont (0.3%), Maine (0.6%), Connecticut (0.8%), and New York (0.8%) all have seven-day averages below 1%.