Younger children more likely to spread COVID-19 in homes than older children, study says

A new study suggests that younger children are more likely to spread COVID-19 within households compared to older children.

The study, published in The Journal of American Medicine Association, said the highest odds of transmission were in children between 0 and 3 years old compared to children between 14 and 17 years old. Children between 4 and 13 years old also had increased odds of transmitting the virus but not as high compared to the younger demographic. 

Researchers studied more than 6,000 households in Canada between June 1 and December 31, 2020, to gather results. 

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"As the number of pediatric cases increases worldwide, the role of children in household transmission will continue to grow," the researchers wrote. "We found that younger children may be more likely to transmit SARS-CoV-2 infection compared with older children, and the highest odds of transmission were observed for children aged 0 to 3 years."

The study said the differences in transmission rates among children may be due to viral shedding, symptom expression and behaviors, such as the inability to socially distance themselves and self-isolate, but researchers pointed out that further research is needed.

However, the researchers noted that children don’t seem to spread COVID-19 as frequently as adults.

With the highly contagious delta variant spreading across the U.S., children are filling hospital intensive care beds instead of classrooms in record numbers, more even than at the height of the pandemic. Many are too young to get the vaccine, which is available only to those 12 and over.

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Very high infection rates in the community "are really causing our children’s hospitals to feel the squeeze," said Dr. Buddy Creech, a Vanderbilt University infectious disease specialist who is helping lead research on Moderna’s vaccine for children under 12. Creech said those shots probably won’t be available for several months. Pfizer’s shot is available for that age group now.

While pediatric COVID-19 hospitalization rates are lower than those for adults, they have surged in recent weeks, reaching 0.41 per 100,000 children ages 0 to 17, compared with 0.31 per 100,000, the previous high set in mid-January, according to an Aug. 13 report from the Centers for Disease Control and Prevention.

Dr. Francis Collins, head of the National Institutes of Health, calls the spike in cases among children "very worrisome."

He noted that over 400 U.S. children have died of COVID-19 since the pandemic began. "And right now we have almost 2,000 kids in the hospital, many of them in ICU, some of them under the age of 4," Collins told FOX News earlier this month.

Health experts believe adults who have not gotten their shots are contributing to the surge among grownups and children alike. It has been especially bad in places with lower vaccination rates, such as parts of the South.

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Studies are underway to test COVID-19 vaccines in children younger than 12 years old. 

Two COVID-19 vaccine manufacturers — Pfizer-BioNTech and Moderna — have agreed to expand their studies to include more children between 5 and 11 years old following a request from the U.S. Food and Drug Administration.

According to the U.S. Centers for Disease Control and Prevention, more than 170 million Americans ages 12 and up are fully vaccinated, representing 60.1% of the demographic. 

The Associated Press contributed to this report. This story was reported from Los Angeles.