Report Predicts Second COVID-19 Surge in State

COVID-19 is still spreading at epidemic rates in Wisconsin and 23 other states. That’s according to a study from the Imperial College London, a public research university in the United Kingdom, based on mobility data from Google and case and death data from John Hopkins University.

The study’s model predicts a second surge based on increased mobility in the 24 states resulting in the number of deaths tripling over the next two months.

The study is focused on the reproductive number (R-value), or the number of people each individual with the disease infects. “Our model uses mobility to predict the rate of transmission, neglecting the potential effect of additional behavioural changes or interventions such as testing and tracing,” wrote the study authors.

An R-value below one would lead to a reduction in cases of the disease. The study estimates Wisconsin’s rate is above 1 currently, but down from earlier in the outbreak. The Milwaukee County COVID-19 Intel Team released a report last week that showed the rate was increasing in Milwaukee County and is currently at approximately 1.2.

The study estimates that the virus is reproducing faster in only nine other states: Alabama, Iowa, Indiana, Minnesota, Ohio, Colorado, Illinois, Arizona and Texas. A total of 24 states are estimated to have R values in excess of 1.

“Our estimates suggest that the epidemic is not under control in much of the US,” wrote the study authors. “These estimates suggest that caution must be taken in loosening current restrictions if effective additional measures are not put in place.”

The study’s Bayesian model estimates 1.2 percent of Wisconsin residents had the disease as of May 17th (within a 95 percent credible interval of 0.8 to 1.8 percent), below the national average estimate of 4.1 percent, every state bordering Wisconsin (2.5 to 7.1 percent) and far below many states in the northeast.

The model, as of May 17th, also estimates that 7,000 people were infectious in Wisconsin, but within a window of 1,000 to 22,000 people.

“We predict that deaths over the next two-month period could exceed current cumulative deaths by greater than two-fold, if the relationship between mobility and transmission remains unchanged,” wrote the authors. “Our results suggest that factors modulating transmission such as rapid testing, contact tracing and behavioural precautions are crucial to offset the rise of transmission associated with loosening of social distancing.”

The Wisconsin Supreme Court struck down the state’s Safer at Home order on May 13th and only a handful of communities, including Dane County and the City of Milwaukee, continue to have local orders in place.

On Tuesday, the Department of Health Services and Wisconsin Hospital Association reported that COVID-19 hospitalizations have reached a 30-day high at 422, below an early April peak of 446. But the number of new cases was at a seven-day low of 279.

“Clearly we are in a critical and fragile period,” said Milwaukee County medical services director Dr. Ben Weston during a Tuesday afternoon press briefing. “We must be especially careful in our dialing back of physical distancing.”

The Imperial College model accounts for factors like population density, when a state first reached 10 deaths, time spent at transit hubs, gas stations and other businesses and when public health orders were eased or removed. It does not account for changes in behavior, including the introduction of widespread mask wearing. It has not been peer reviewed.