As states throughout the U.S. lift stay-at-home orders, reopen businesses, and relax social distancing measures, Johns Hopkins has created an online graph that shows whether cases of COVID-19 are increasing, decreasing, or remaining constant within each state.
Federal guidelines advise that states wait until they experience a downward trajectory of documented cases within a 14-day period before proceeding to a phased opening. Lifting social distancing measures prematurely, while cases continue to increase or remain at high levels, could result in a resurgence of new cases.
In this visualization, states that appear in shades of orange have experienced a growth in new cases over the past two weeks. States that appear in shades of green have seen declines in cases over the same period of time. The shade of the colors indicates the size of each state’s growth or decline in new cases; the darker the shade, the bigger the change.
In addition, Johns Hopkins has also introduced their International Comparison of Positivity Rates and Tests Per Capita report. It shows the all-time average of each country’s daily positivity and daily tests conducted per capita. The U.S. has conducted more COVID-19 tests than any other country. However, there is no expert consensus on a recommended target for the raw number of tests or even the rate of tests per capita – and these statistics alone can be misleading.
In order for governments to identify new cases and effectively respond to the pandemic through tracing and treatment, testing programs should be scaled to the size of their epidemic, not the size of the population. In the visualization, you’ll see that several countries effectively controlled the spread of the virus through testing programs that had a far lower number of tests per capita than the U.S. Meanwhile, despite having the highest rate of tests per capita, the U.S. faces the largest outbreak in the world and new cases continue to trend upwards in many states.
Looking at the positivity rate (ie, out of all tests conducted, how many came back positive for COVID-19) is the most reliable way to determine if a government is testing enough. A high rate of positive tests indicates a government is only testing the sickest patients who seek out medical attention and is not casting a wide enough net. The World Health Organization (WHO) has issued guidance stating that governments should see positivity rates below 5% for at least 14 days before relaxing social distancing measures.
