Sept. 6, 2022 – Don’t count on a runny nose.
Young kids with COVID-19 often have no symptoms at all, even when they have a high amount of the virus in them, according to a new study.
Just 14% of adults who tested positive for SARS-CoV-2, the virus that causes COVID-19, had no symptoms of the disease, versus 37% of children up to age 4, the researchers found.
This raises concern that parents, childcare providers, and preschools may not be seeing the level of infection in seemingly healthy young kids who have been exposed to COVID-19, wrote lead author Ruth A. Karron, MD, and colleagues in the Journal of the American Medical Association Open.
The study involved 690 people from 175 households in Maryland who were monitored closely between November 2020 and October 2021. Every week for 8 months, they completed online symptom checks and had PCR testing – which detects the presence of the virus causing COVID-19 – done with nasal swabs. Those with symptoms submitted more swabs for analysis.
“What was different about our study [compared with previous studies] was the intensity of our collection, and the fact that we [tested those who did not have COVID symptoms],” Karron, a pediatrician and professor in the Department of International Health at Johns Hopkins University in Baltimore, said in an interview. “The fact that we were sampling every single week meant that we could pick up those early infections.”
The study also stands out for its focus on young children, Karron said. All households that took part in the study had at least one child up to 4 years old, with 256 out of the 690 people (37.1%) in this youngest age group. The other people in the study were 100 children ages 5 to 17 (14.5%) and 334 adults ages 18 to 74 (48.4%).
Youngest Were Most Likely to Not Have Symptoms
By the end of the study, 51 people had tested positive for the coronavirus, including 14 who had no symptoms. A closer look showed that children ages 4 and younger who got COVID-19 were more than twice as likely to not have symptoms as infected adults (36.8% vs. 14.3%).
The relationship between symptoms and viral load – the amount of the virus that causes COVID in a person – also differed between adults and young children.
While adults with high viral loads – suggesting they were more contagious – typically had more severe COVID-19 symptoms, that was not the case with young kids. This suggests that children with mild or no symptoms could still be highly contagious.
Karron says these findings should help parents and others make better decisions. She says that even if young children don’t have symptoms, they should be tested for COVID-19 if they have been exposed to others with the disease. And she recommends acting on the results.
“If a family is infected with the virus, and the 2-year-old [has no symptoms], and people are thinking about a visit to elderly grandparents … one shouldn’t assume that the 2-year-old is uninfected,” Karron says. “That child should be tested along with other family members.”
Testing should also be considered for young children exposed to COVID-19 at childcare facilities, she says.
But other experts did not necessarily agree.
“I question whether that effort is worth it,” says Dean Blumberg, MD, a professor and chief of the Division of Pediatric Infectious Diseases at UC Davis Health in Sacramento, CA.
He notes that recent FDA guidance for COVID-19 testing calls for three negative at-home antigen tests – which detect proteins, called antigens, from the virus that causes COVID-19 – to confirm lack of disease.
“That would take 4 days to get those tests done,” he says. “So, it’s a lot of testing. It’s a lot of record keeping, it’s inconvenient, it’s uncomfortable to be tested, and I just question whether it’s worth that effort.”
Do the Findings Still Apply?
Blumberg also questions whether the study, which was completed almost a year ago, reflects the current pandemic landscape.
Although the experts interviewed had different opinions of the findings, they shared similar views on vaccination.
“The most important thing that parents can do is get their kids vaccinated, be vaccinated themselves, and have everybody in the household vaccinated and up to date for all doses that are indicated,” Blumberg says.
Karron notes that vaccination will be more important in the coming months.
“Summer is ending; school is starting,” she says. “We’re going to be in large groups indoors again very soon. To keep young children safe, I think it’s really important for them to get vaccinated.”