INDIANAPOLIS (AP): A statewide study estimates that at least 2.8% of Indiana’s population has been infected by the coronavirus, a rate about 10 times that shown by previous testing, Indiana University researchers said Wednesday.

The testing of about 4,600 people at random around the state found 1.7% were infected at the time of the test and 1.1% tested positive for antibodies showing they were previously exposed. The tests were done by IU’s Fairbanks School of Public Health over a week ending May 1.

The findings project that Indiana has seen a 0.58% fatality rate among those infected. That rate is almost six times greater than the death rate for seasonal flu, said Nir Menachemi, a professor who led the study.

Nearly 45% of those infected reported experiencing no symptoms of the COVID-19 respiratory disease. Menachemi said that highlighted the need for people to practice social distancing and wear masks in public to avoid unknowingly spreading the coronavirus.

“The need to minimize the risk of infection spread will probably not go away until we have a vaccine or a really good treatment that can deal with everyone infected,” Menachemi said.

A statewide order from Gov. Eric Holcomb started lifting many business and travel restrictions starting May 4.

Menachemi said the IU researchers plan a new round of random testing in early June that will look for any increased coronavirus spread connected with the state’s reopening steps.

“We’ll get the first glimpse of how the relaxing of some of the issues have impacted the population,” he said.

The projected infection rate would mean about 186,000 Indiana residents had the coronavirus by the end of April, when the state health department reported fewer than 19,000 confirmed infections. The agency reported nearly 25,500 infections as of Wednesday.

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.