Your State Should Lock Down Again Once It Hits This Exact Benchmark
If this metric gets to a certain point, it's time to mask up and hunker down.
The United States just reached four million COVID cases, a million of which were reported in the last 15 days. The troubling surge has been driven by major outbreaks in populous states like California, Texas, and Florida, which have become the new epicenters of the pandemic. But many other states have reason to be concerned, as well. You've likely read about which states should be returning lockdown, based on assessments from a variety of medical and public health experts. The COVID Risk Level map from the Harvard Global Health Institute (HGHI), for example, breaks down each state into one of four color-coded risk level categories (green, yellow, orange, and red) based on their number of new cases per day. According to the Harvard researchers' assessment, once a state reaches 25 new cases per 100,000 people per day, it's time to shutdown. "Once a community reaches the red risk level, stay-at-home orders become necessary again," the researchers note.
At the time this article was published, 11 states were at that point: Florida (58.6 new cases per 100,000 people); Louisiana (46.8); Mississippi (41.1); Nevada (38.0); Arizona (37.8); Alabama (37.1); Texas (36.9); South Carolina (35.2); Georgia (32.9); Tennessee (31.1); and Idaho (31.0).
But why do 25 new cases per 100,000 people indicate that a state should be instituting stay-at-home orders again? During a call with press on July 24, Thomas Tsai, MD, assistant professor at the Department of Health Policy and Management at Harvard T.H. Chan School of Public Health, explained the reasoning to Best Life.
"The cases are hard because they're very much influenced or potentially biased by how aggressive you are testing," Tsai said. "That's why we have a separate dashboard for what the test positive rate should be."
Tsai noted that the July 14 leaked document from the White House showed their barometer for a "red zone" was similar. "They look at the combination of both the number of new cases as well as the test positive rate," Tsai said. The White House's cut-off for the "red zone" is over 100 new cases per 100,000 people per week and/or a 10 percent test positive rate.
But, Saskia Popescu, PhD, an infectious disease epidemiologist in Arizona, told Best Life that "something like percent positive can be misleading if there's not enough testing being done." According to Tsai, the HGHI sees positive test rate as a complex marker to depend on solely without looking at the full picture. "It really depends on what the testing strategy of that state is. Are they just trying to catch up with a growing number of cases in a community versus do they have a really robust surveillance network?" Tsai said.
Tsai recognized that death rates may seem like the obvious choice to measure how dire a state's situation is. But it's similarly not always the best indicator. "We had considered looking at mortality, which is obviously the most objective measure of COVID-19," he said.
The Institute for Health Metrics and Evaluation (IHME) at the University of Washington, for example, has been projecting the death toll coronavirus will take on the U.S. for the past several months. They suggest the country will have to impose stay-at-home orders when deaths per day reach 8 per million people.
"The issue with mortality, as we've seen over the last several weeks, several months, is that it's very much a lag indicator," Tsai said. "There's actually even delays in how mortality is reported."
Ultimately, Tsai said, the HGHI dashboard was a collaborative effort with researchers from many different teams across the country to show each state's COVID risk level. "The new cases was in some ways the most intuitive for the public to understand. It's the one that's reported the most," he pointed out. "So that drove the categories of response."
According to Popescu, state officials should be looking at a slew of COVID-related factors, including the aforementioned positive test rate and death rate, as well as infection rate, hospitalizations, and number of tests being done, in order to determine whether or not another lockdown is needed. "It's hard to pick just one as they all share an important piece in understanding the true situation," she said. "Most often, I see people focusing on hospitalizations and infection rates a lot, but also positivity rate. Hospitalizations and deaths are good indicators for healthcare capacity, while testing and positive rates give insight into the community."
But if you see your state reach that 25 new cases per 100,000 per day mark, it may be time to consider quarantining again. And for more on that, check out The CDC Just Made This Major Change to Its Guidelines.