More than 25% of kids with COVID-19 spread it to others in household, study finds

While children were thought to be at lower risk of acquiring or spreading COVID-19 earlier in the pandemic, researchers now say 1 in 4 kids is the cause of household spread of the disease. File Photo by John Angelillo/UPI | License Photo

Aug. 16 (UPI) -- One in four children with COVID-19 spreads the disease to other members of their households, with the highest risk for virus transmission among infants, a study published Monday by JAMA Pediatrics found.

In the analysis of nearly 6,300 households with at least one pediatric case of infection, more than 1,700, or 27%, saw another member become sick with the virus, the data showed.

Newborns and children up to age 3 were 43% more likely to pass the virus to others in their households than those age 14 to 17, the researchers said.

The study focused on pediatric cases among households Ontario, Canada, confirmed between June 1 and Dec. 31, or before the more contagious Delta variant of the virus became the predominant one in the region.

"As the number of pediatric cases increases worldwide, the role of children in household transmission will continue to grow," wrote the researchers, from Public Health Ontario, a provincial agency.

"We found that younger children may be more likely to transmit [COVID-19] infection compared with older children, and the highest odds of transmission were observed for children aged 0 to 3 years," the researchers said.

The role of children in spread of the virus has been the subject of much debate since the pandemic started.

At least early on, studies suggested children were at lower risk for infection and, thus, disease spread.

However, in recent months, with the emergence of the Delta variant in the United States and elsewhere, an increasing number of children have developed severe COVID-19.

Nationally, nearly 2,000 children were hospitalized with the virus through Saturday, a record high, according to data from the Department of Health and Human Services.

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This is a cause for concern, particularly as schools across the country begin to reopen, officials with the Centers for Disease Control and Prevent said earlier this month.

For this study, the Public Health Ontario researchers analyzed COVID-19 spread among nearly 90,000 households in the province over a seven-month period.

Among the households included in the analysis, about 6,300, or 7%, had at least one confirmed pediatric case of the virus, the data showed.

About 12% of the pediatric cases were in children 3 years and younger, while 20% involved children ages 4 to 8, 30% occurred in children ages 9 to 13 and 38% were in children ages 14 to 17.

Nearly 31% of households with an infected child age 3 or younger saw at least one "secondary" case, or instance of virus spread -- the highest percentage of any age group.

It is possible that younger children have similar levels of virus in their bodies -- or viral loads -- as adults, which leads to higher transmission, they said.

"Differential infectivity of pediatric age groups has implications for infection prevention controls within households and schools [and] childcare [facilities] to minimize risk of house-hold secondary transmission," the researchers wrote.

"As it is challenging and often impossible to socially isolate from sick children, caregivers should apply other infection control measures where feasible, such as use of masks, increased hand washing and separation from siblings," they said.

In a commentary entitled "Yes, Children Can Transmit COVID, but We Need Not Fear," published with the study, authors from the University of Pennsylvania add, "the obvious solution to protect a household with a sick young infant or toddler is to make sure that all eligible members of the household are vaccinated."