State officials announced the preliminary results of the second phase of a study conducted by the Indiana University Richard M. Fairbanks School of Public Health at IUPUI to measure the spread of the new coronavirus in Indiana, saying active infections in Indiana have decreased since late-April.
The Indiana State Dept. of Health partnered with the school to conduct a random-sample study of Hoosiers to gain an estimate of the number of residents infected with COVID-19 or were previously infected.
The study tested 3,619 people during its second phase, from June 3 to June 8. Of the 3,619 tested, 2,668 were pulled from random sampling and another 951 were supplemental outreach samples from Marion, Allen and LaGrange counties.
A third phase of the study, scheduled for four, is set for fall, and a fourth phase is scheduled for spring 2021. The first phase was completed in late-April. Researchers said Indiana is the first state in the country to successfully have completed multiple phases of a random-sample study of its residents.
Preliminary data from the second phase of testing showed active infections in Indiana have decreased from 1.7 percent in Phase 1 to 0.6 percent in Phase 2. Likewise, antibody testing showed more Indiana residents have antibodies for the disease – meaning they previously had COVID-19 – in Phase 2. Only 1.1 percent of residents tested positive for antibodies in Phase 1; 1.5 percent tested positive for them in Phase 2.
Researchers also said the results led them to believe the spread of the virus was limited to households and kept out of the community due to social-distancing measures implemented in March. During Phase 2, researchers found 21.5 percent of random-sample test subjects said a doctor informed someone living in their household they may have tested positive for COVID-19, and 35 percent of outreach sample patients reported the same, while 10.5 percent said no one they live with was notified, compared to 1.7 percent of the random-sample test subjects.
Results further corroborated evidence that minorities have suffered from the disease more than Whites. In Phase 2, 0.4 percent of Whites tested positive for COVID-19, less than the 1.5 percent who tested positive in Phase 1. Non-whites had a positive result rate of 1.4 percent in Phase 2, a decrease from 3.4 percent in Phase 1. While antibody rates held almost the same for Whites – 1.0 percent in Phase 1, 0.9 percent in Phase 2 – minorities saw antibody rates sharply increase from 1.6 percent in Phase 1 to 5.6 percent in Phase 2.
Hispanic residents, particularly, showed higher rates of active infections – 2.6 percent in Phase 2, compared to 0.4 percent of Non-Hispanics – and antibody rates: 8.5 percent of Hispanics tested positive for antibodies, and only 1 percent of Non-Hispanics tested positive.
The study found 43 percent of positive COVID-19 cases were asymptomatic at the time of testing. In the study’s first phase, it found 44.8 percent of cases to be asymptomatic. Indiana State Health Commissioner Dr. Kristina Box said the high number of asymptomatic cases underscores the importance of mask wearing, which she says protects others from mask-wearers, hand washing and continued social distancing.