Testing for the coronavirus that causes COVID-19 has dropped nationwide the past two weeks even as the evidence builds disease spread is picking up in many states.
Nowhere is the danger of the testing slowdown more evident than the South. In Mississippi, more than one in five tested for the virus in the past week were positive, the highest rate in the nation as of Friday. The average number of daily tests in Texas and Florida dropped but the ratio of positive tests in each state is more than double what the World Health Organization recommends.
Official case counts have dropped nationally but reporting problems and generally reduced testing in some states makes it hard to place any confidence that infection rates are improving. And in some states with more reliable data, testing slowdowns coincide with increasing or stable positive rates.
“The enhanced positivity rate is the thing that bothers people more than anything else,” said Dr. William Schaffner, a professor of preventive medicine and infectious disease specialist at Vanderbilt University School of Medicine. “Because it suggests this virus is circulating still very briskly, especially in certain parts of the country. In fact, much of the country.”
The WHO recommends 5% or fewer tests should be positive two consecutive weeks before a community loosens restrictions on businesses opening. If a positive test rate is above that benchmark, it’s a sign an area is only testing the sickest patients and not adequately tracking the virus.
The average number of coronavirus tests reached 793,000 per day in the last two weeks of July. But testing dropped to fewer than 650,000 per day during the first 12 days of August, according to figures from the COVID Tracking Project.
More than half of states nationwide have positive rates above 5%, and a dozen states are above 10%.
As testing has slowed, positive rates increased over the last week in 35 states as of Friday, according to Johns Hopkins University’s Coronavirus Resource Center.
“If testing is going down and positivity is going up, that is what you would expect in an uncontrolled outbreak,” said Amesh Adalja, a senior scholar at Johns Hopkins Center for Health Security.
Although positive rates are still too high, Adalja sees positive signs such as fewer hospitalizations and declining case counts.
Experts believe several factors are leading to a testing decline in parts of the nation.
A surge in testing demand in July showed more Americans sought tests than the nation’s labs could process in a timely manner. Even when people got tested last month at a doctor’s office, testing site or clinic, wait times ballooned – making it too late to trace contacts of an infected person.
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Storms temporarily closed testing centers in states such as Florida, New York and New Jersey. And people might be more relaxed after an early summer surge in the South and West relented and case counts drop.
But experts say dropping case counts can be a deceiving sign when the share of positive tests holds steady or increases.
Texas probes higher positive rate
Texas Gov. Greg Abbott acknowledged this week testing had dropped and positive rates increased, but he announced more surge testing would help get the state’s positive rate back down to 10%.
In Texas, the one-week average for positive rates reached 24.5% before dropping to 16% on Wednesday. The rate dropped even more, down to 12%, as of Friday, according to the Texas Department of State Health Services.
The state health department is investigating the high rate of positive tests as the number of hospitalized COVID-19 patients decreases. The lab reporting system was upgraded Aug. 1 and a hospital lab and commercial lab resolved coding errors. Fewer people also visited community testing sites, a spokeswoman said.
The state also is working to clear a backlog of 1.1 million “pending” tests that had incomplete paperwork or were not assigned to the patient’s home county. Those cases already have been counted in the totals and would not affect positive rates, the spokeswoman said.
Angela Clendenin, an epidemiologist at Texas A&M University School of Public Health, said too many Texans don’t pursue testing because there’s still confusion over who’s eligible for testing. Other factors include a belief that things are safer after the governor ordered people wear masks, closed bars and limited restaurant seating.
“It’s a false sense of security,” she said.
Testing reluctance persists
Fatigue and skepticism also are factors, Clendenin said, especially among people whose social circles or communities have had few infections.
“If you don’t know anybody who’s been infected by COVID-19, why are you going to worry about it?” Clendenin said. “There’s been a lot of skepticism about the evidence and science behind the guidance we are providing.”
Although Texas case counts have dropped the last week, she said the drop in testing is concerning. “The high positivity rate is indicative of the fact all we’re doing is testing symptomatic people.”
Others cite an urban-rural divide on testing. Metro regions have abundant testing options, easy access and people more willing to get tested. But some rural resident are far more skeptical, especially if they live in a community where there are few known cases.
“There are still many parts of the country, and as you get more rural, the notion becomes stronger, they’re really questioning the validity of all of this information,” Schaffner said. They think, “‘Is this all really all just a hoax of some sort?'”
Schaffner sees the skepticism in Tennessee’s rural counties where “compliance just plummets” on proven strategies of social distancing, mask wearing and testing. The state’s testing has remained stable but the positive rate ticked up slightly in the past week to a still manageable 8%.
“If we had more testing, I think we’d find more cases, find more people who are genuinely sick and many who have only minimal symptoms, documenting that this is a virus that truly is circulating in rural communities, as all of us think it is,” he said.