March 16, 2020 – New research found that overall children in China infected with the novel coronavirus (SARS-CoV-2)showed less severe symptoms of illness than adults, though infants and toddlers were vulnerable to moderate and severe infection.
The study, “Epidemiological Characteristics of 2143 Pediatric Patients with 2019 Coronavirus Disease in China,” examined the cases of 731 children with confirmed laboratory-tested cases of the coronavirus and 1,412 children who were suspected of having COVID-19.
The retrospective study of cases reported between Jan. 16, 2020 and Feb. 8, 2020, will be published in the June 2020 issue of Pediatrics, and is available online March 16.
Out of all 2,143 cases, one child died, and most cases were mild. Nearly 6% of the children’s cases were severe or critical compared with 18.5% of adults.
Researchers aren’t sure why children with COVID-19 were not as ill as the adults.
“There could be a number of reasons,” said Bonnie Maldonado, MD, FAAP, chair of the AAP Committee on Infectious Diseases, who was not involved with the study. “It’s possible that the receptor for the virus may not be in the same configuration in children as adults. It’s possible that there were just more adults who were tested because that has been the focus. However, there have been other studies of pregnant women and children who did not have as severe disease.”
“I suspect the immune response of children is different,” she said. “Their immune system is young and evolving.”
Dr. Maldonado said this is not the first time they have seen a novel coronavirus affect specific populations while sparing others. Pregnant women and children, for instance, became sicker with the H1N1 influenza when compared with others.
In the case of the COVID-19, “it especially seems to be sparing young children.”
The study concluded, however, that infants and young children were vulnerable to the novel coronavirus, SARS-CoV-2infection. Researchers also concluded that the study provides strong evidence for human-to-human transmission. More than 90% of all pediatric patients were asymptomatic, showing mild or common forms of illness. About 13% of patients who tested positive for this virus did not show symptoms of illness, a rate that “almost certainly understates the true rate of asymptomatic infection, since many asymptomatic children are unlikely to be tested,” according to a solicited commentary published in Pediatrics by Andrea T. Cruz, MD, MPH, and Steven L. Zeichner, MD, PHD.
Many questions remain unanswered, Dr. Maldonado said.
“Studies need to be done as soon as possible to understand the differential impact between adults and children, because that information could be helpful,” she said.
When the disease is apparent, it might be possible to contain it faster. What is unknown is if children who show no symptoms of illness can act as vectors in spreading it to others.
Dr. Maldonado described the study as helpful but said more research and testing in the U.S. is needed.