A new study conducted by the Indiana University Medical School found asymptomatic carriers of COVID-19 make up only 0.2% of cases in Marion County.
The Tracking Asymptomatic COVID-19 Through Indianapolis Communities (TACTIC) study sampled a group of people — with demographics that similarly reflect the various communities in Indianapolis — to determine the rate of people unknowingly living with the virus.
“The rate of people that had infection without symptoms was low,” Dr. Jim Wood, co-leader for the study and assistant professor of pediatrics at the IU School of Medicine, said. “We think that asymptomatic people, and especially young people, are less likely to pass it on. That’s not something we can definitively say from this study, that’s just us extrapolating.”
However, Wood said this theory is backed up by various studies focused on asymptomatic transmission.
To find volunteers, Wood and Dr. Chandy John, the study’s other co-leader and director of the Ryan White Center for Pediatric Infectious Disease and Global Health at the IU School of Medicine, implemented the All In for Health database.
“We wanted to study children, because a lot of the good work the state has done has focused on adults of various ages,” Wood said. “We wanted to focus on families with small kids, and it was also important to get a reflection of our community here in Marion County.”
Wood and John sent out the first wave of study information to underrepresented minority communities, who have been hit the hardest by COVID-19. Although the sample size wasn’t large enough to break the findings down by race, ethnicity or gender, John said the 0.2% — the number of people infected with the virus while showing no symptoms — should be fairly similar among various demographics because of the diversity of the study population.
The study also shed light on how COVID-19 affects children.
Of the 511 individuals tested via a self-administered nasal swab, only 1 person — an asymptomatic 7-year-old child — tested positive. The five people living with the child all tested negative and continued to do so with subsequent tests.
“One of the major takeaways of this study is that there can be asymptomatic COVID-19 infection in children in the community who are younger than 10 years old,” Chandy said in a statement. “Additionally, we now know that asymptomatic infection can occur in young children with no known contact to the virus, and they do not necessarily spread it to others. Community studies in other countries have not found this.”
While Wood stressed that transmission from asymptomatic carriers is low, but not impossible, he’s optimistic about what these findings mean for returning to in-person learning.
“I think that this is a small piece of the puzzle that we’re all putting together,” Wood said. “I’m more optimistic in recent weeks that maybe kids don’t spread quite as much, and if schools take proper precautions, we can return to in-person school safely.”
Despite previous studies that hinted asymptomatic carriers may be more likely to spread the virus — due to not taking appropriate precautions because of perceived negativity — Wood said it’s logical to assume people without symptoms are less contagious.
“We don’t have a great idea as to why kids and asymptomatic people don’t spread it quite as much,” Wood said. “It could be due to specific biology that’s different that we don’t understand yet. But, it’s possible when people don’t have symptoms, they might not have as much of the virus as people with symptoms do. When you have symptoms, like a cough, it stands to reason that you’re more likely to spread the virus because you’re creating more of those [respiratory] droplets.”
The next step for Wood and John is TACTIC 2, a follow-up study with the same participants to determine whether they’ve developed antibodies to the virus.
While no one has a clear understanding of the novel coronavirus, Wood believes precautions taken by state and city officials, such as mask mandates and shutdowns, have had a positive impact on the spread of the disease. Despite his optimism that Marion County is on the right track, however, he doesn’t believe the county is at the point where we can start getting back to normal.
“We’re not there yet. All the little things we can do add up and keep people safe,” Wood said. “Although social distancing and masks aren’t easy, there’s a trade-off. We have to continue to be safe and follow mitigation strategies. … I’m afraid if we stop right now, we’ll go right back to where we were at the beginning.”
Contact staff writer Breanna Cooper at 317-762-7848. Follow her on Twitter @BreannaNCooper.
