A new data-driven mathematical model of the coronavirus pandemic predicts that the United States will peak in the number of “active” COVID-19 cases on or around April 20, marking a critical milestone on the demand for medical resources.
“This indicates an important turning point that each country will reach in the COVID-19 pandemic, and we predict that the United States is on course to reach this point in the coming weeks,” says Ka-Kit Tung, a professor of applied mathematics at the University of Washington. “It is a point of maximum strain on a country’s health and medical infrastructure.”
The new model is intended to help health officials and policymakers see at least two weeks in advance how COVID-19 will likely strain medical infrastructure in the U.S. and around the world. It relies on the number of newly diagnosed cases and the number of individuals who have recovered or died in a geographic region—whether an entire country or a subnational level like a state or province.
For the U.S., this model predicts that:
- The rate of daily new COVID-19 cases peaked on April 5-7, a projection that appears to be accurate, according to Tung.
- The number of “active” COVID-19 cases, which are individuals who have been diagnosed but haven’t recovered or died, will peak on April 20, plus or minus four days, and will then slowly decline as the number of cases entering the medical system becomes less than the number of cases leaving the medical system.
- The U.S. outbreak will taper off in the first week of June with projections of 710,000 total cases, but could be up to 990,000, and 28,000 deaths, but could be up to 39,000, if the current U.S. fatality rate of 4% holds
Their model also predicts that other hard-hit countries, such as Germany and Spain, have either recently peaked in active COVID-19 cases or will do so soon. The United Kingdom will not peak until the latter half of April, according to the analysis.
Scientists at the UW’s Institute for Health Metrics and Evaluation have created a separate data-driven model for COVID-19, which relies on other pieces of information about the pandemic, such as observed death rates. In contrast, the model by Tung uses the number of newly diagnosed cases and the number of individuals who have recovered or died. The Institute’s model primarily projects COVID-19 deaths in a region, as well as the demand for hospital resources such as ventilators.
“Our two approaches complement one another, providing the projections that health officials and governments need to understand when the maximum strain on resources is coming, and to show how the course of the pandemic depends heavily on the level of social distancing measures adopted,” says Tung.