May 6, 2022 - Podcast

Episode 264 — COVID-19 antibodies, and reducing lead exposure

As the COVID-19 pandemic continues, researchers are learning more about its effect on different populations. Indiana University School of Medicine pediatric researcher Chandy John and colleagues have been studying neutralizing antibodies in children and how immunity to COVID-19 can develop and change over time. Their latest results indicate that children develop neutralizing antibodies to COVID-19 at similar levels to adults, and those antibodies last longer in children. John says this differs from early research, which suggested children developed fewer antibodies and that their immunity did not last as long, but the latest results are consistent with more recent research. However, researchers found that antibody levels after infection were much lower than antibody levels seen after vaccination. The results show that infection in children leads to antibodies that could protect to some degree against future infection or disease, but antibody levels are lower, and so probably less protective, than those after vaccination, he says. John and his colleagues studied 94 children between the ages of 6 months and 17 years, as well as 344 adults, dividing them into four groups: people who had symptoms of COVID-19 and tested positive for the disease; people who had symptoms of COVID-19, but tested negative or were not tested; people who did not have symptoms of COVID-19, but had been exposed to the disease; and people who did not have symptoms of COVID-19, and had not been exposed to the disease. Researchers tested the children in each of these groups for COVID-19 antibodies between June and December 2020, and then again six months later. Each child who had tested positive for COVID-19 and were symptomatic developed neutralizing antibodies. The researchers also checked for antibodies in the adults who tested positive for COVID-19, and only 81 percent of them developed neutralizing antibodies. Over time, antibody levels decreased in both children and adults who were originally COVID-positive, but more children than adults still had antibodies by the six-month checkup. Seven of the adults who originally tested positive for COVID-19 received a COVID-19 vaccine before their six-month visit, and researchers compared their antibody levels to those in the study who were previously infected with COVID-19 but did not receive a vaccine. They found that antibody levels were more robust in those who received the vaccine. John says this study shows how important it is to get children vaccinated against COVID-19. Since antibody levels wane over time after infection or vaccination, it’s likely that children may need a booster to make sure they have enough protection from the disease to prevent them from getting sick, he says.

In other news, what was once an abandoned lot on Indianapolis’ Far Eastside is now home to newly planted trees, vegetable beds and walking paths. The rehabbed lot is part of a pilot project and research study to determine if transforming these spaces can mitigate lead exposure. The study, led by researchers at IUPUI, will examine whether the newly placed mulch, plants and grasses will decrease people’s likelihood of interacting with the contaminated soil. Researchers have periodically taken soil samples at the lot to test them for the presence of lead. The results of this study could determine the locations of future green spaces. Researchers observed that people used the lot, even though it was abandoned. As children play on the lot, dust could be kicked into the air and carried home on the bottom of shoes. Lead-contaminated dust, if inhaled or ingested, can have serious health consequences for children. Exposure to environmental contaminants severely impacts brain development of children in many neighborhoods, and this affect is seen disproportionately in lower income communities of color, says Gabriel Filippelli, executive director of IU’s Environmental Resilience Institute. Sources of lead in soil can include lead-based paint, contamination from manufacturing and lead-based gasoline. Lead exposure, especially in children, has been a concern for many years, and a new law offers lead testing for all Indiana children under the age of six through their doctor. The study will test soil from several lots, and full results are expected to publish in spring 2023.