INDIANAPOLIS — A study measuring the prevalence of COVID-19 in Indiana found that as of early October approximately 7.8 percent of the state's population had been infected with the novel coronavirus.
Based on the methodology from the third phase of the study and previous phases, researchers from IUPUI estimated that as of Nov. 20, the number of Indiana residents ever infected by COVID-19 has increased to 10.6 percent of the population.
According to IUPUI, the first phase of the study in April found a prevalence of 2.8 percent.
"COVID-19 infections are rising across the state, and we are far from achieving herd immunity," 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 and IU Fort Wayne, said. "Without a vaccine, if the virus continued to spread unabated, over 13,000 Hoosiers would lose their lives, outside of nursing homes, to reach herd immunity of 70 percent infected. That is several times more deaths than have already occurred outside of nursing homes in Indiana."
According to IUPUI, from October to November, the number of cumulative infections increased 2.8 percentage points overall, with the highest increase in people age 30 to 49 years old (11.7 percent to 16.5 percent).
Researchers said the total number of Indiana residents ever infected over the age of 65 increased from 4.3 percent to 6.9 percent.
"As more younger people are becoming infected, the virus is being spread to older, more vulnerable groups of people," Menachemi said. "While younger people are less likely to die from infection, they could be unknowingly spreading the infection to others who might be at higher risk."
According to IUPUI, Menachemi and the other members of the research team have contributed a number of key pieces of knowledge about COVID-19:
- Finding that more than 40 percent of individuals infected with COVID-19 are asymptomatic.
- Calculating the first generalizable infection-fatality rate for COVID-19 by age, race, ethnicity and sex.
- Originally finding that one out of every 11 true infections was identified by symptomatic testing.
- Identifying the loss of taste and smell as key symptoms specific to novel coronavirus infections.
- Identifying that public health measures, such as shelter-in-place orders, reduced the spread of the virus.
"Because of this study, Indiana is leading the nation in contributing to our collective understanding of COVID-19," Indiana Gov. Eric Holcomb said. "We launched this study to gather high-quality information to shape our decision-making in our response to the pandemic. Now, IUPUI scientists are helping to educate others at state and local governments, as well as other universities, on how to do this type of work."
When the study began, it was the first in the nation to scientifically measure the general population prevalence of COVID-19. It was the first step in being able to develop age-specific infection-fatality rates, which allowed Hoosiers to better understand the risks for vulnerable populations such as the elderly.
During all phases of the study, researchers noted disparities among minority populations, which have been among the hardest hit by coronavirus infections.
"Evidence-based research has never been more important than in our fight against COVID-19," Dr. Kris Box, Indiana State Health Commissioner, said. "This study epitomizes the commitment Indiana has to responding to the pandemic and protecting Hoosier health."
Not enough young child participated in the study to generate reliable estimates for that population.
Additional study is planned in 2021.