Study: 186,000 Hoosiers positive for virus; infection-fatality rate estimated at 1 in 173 cases
INDIANAPOLIS (WISH) — The first phase of a state-sponsored study of the coronavirus estimates about 186,000 Hoosiers had COVID-19 or the antibodies for the novel virus by May 1.
The results were presented Wednesday during a coronavirus briefing from Gov. Eric Holcomb. The four phases of testing are a collaboration of the Indiana State Department of Health and the Fairbanks School of Public Health.
More than 4,600 Hoosiers were selected for testing in the last five days of April, a news release said. The next phases of testing are planned for early June, October and April 2021. Select members of the public will again be asked to participate, by invitation only, to ensure that the sampling is representative of the population.
A news release from the Department of Health said, “The scientists also identified certain communities that have been more affected by COVID-19 than others. Analysis of the random sample suggests that Hispanics, African Americans and other races including those who identify as bi-racial have higher positive rates for the virus.”
“This was confirmed with data from the targeted outreach that allowed us to gain additional participants from these communities — further strengthening the evidence in support of this disparity,” said Nir Menachemi, lead scientist on the study and a professor and Fairbanks Endowed Chair in the Indiana University Richard M. Fairbanks School of Public Health at IUPUI, in the release.
In the first phase, more than 3,600 people were randomly selected and an additional 900 volunteers were recruited through outreach to the African American and Hispanic communities to more accurately represent state demographics.
Menachemi said IUPUI public health researchers determined that during the last week in April, 1.7 percent of participants tested positive for the novel coronavirus and an additional 1.1 percent tested positive for antibodies — bringing the estimated population prevalence of the virus in the state to 2.8 percent, or approximately 186,000 Hoosiers who were actively or previously infected as of May 1. Indiana’s estimated 2020 population is 6.85 million.
“In the same period, the state’s testing showed about 17,000 cumulative cases — excluding deaths — suggesting that only about 1 out of 11 true infections were identified by tests focused on symptomatic or high-risk people,” the release said.
The study estimates an infection-fatality rate of 0.58%. It’s the first time that number includes not just those who were tested and later died, but everyone who has gotten the virus. It equates to 1 death for every 173 cases.
The study also found 44.8 percent of positive cases never reported developing any symptoms.
A positive test in the study was 12 times more likely if someone else in the household had already tested positive for COVID-19.
Menachemi also said preliminary results seem to suggest that the state’s physical distancing policies — also known as social distancing — have played a role in curbing the spread of the virus.
Study participants who reported living with a person in their household who was positive for the virus were more than nine times more likely to test positive themselves. Coupled with the study’s relatively low 2.8% general population prevalence, this seems to imply that Indiana has been able to contain a large number of infections to within households, he said.
“By slowing the spread of the virus, we now have bought some time to determine the best way forward,” Menachemi said in the release. “However, it is important to stress that the vast majority of the people in Indiana have not been infected and represent the minimum pool of still susceptible individuals. Therefore, as we slowly phase back and open the economy, we need to be extra vigilant with any and all safety precautions so that we do not lose the ground that we gained by hunkering down.”