Anyone infected with COVID-19 can spread the virus, but a new study suggests that infected babies and toddlers are more likely to transmit it to others in their homes than teenagers. However, very young kids are less likely to actually bring the virus home than teenagers, say the researchers from Public Health Ontario, Canada. 

The Study Details

The research team analyzed data on positive coronavirus tests and COVID-19 cases in Ontario, Canada between June 1 and December 31, 2020. In more than 6,200 households, the first person to get infected with COVID-19 was under 18. By looking for other cases in those homes in the two weeks after the first child tested positive, the researchers found that 27.3% of the children infected at least one other person in the household. According to the study, published in the journal JAMA Pediatrics, only 12 percent of all first cases in households occurred in children aged 3 or younger, while teens were liable for 38 percent. But the risk of transmission to other people in the home was 40 percent higher when the first case was in a child aged 3 or younger, compared to 14 to 17 years old.  Although the study doesn’t address whether infected children are as contagious as adults, it does suggest that even very young children are active in transmission of the virus. The researchers note that the youngest kids may carry higher levels of the virus or have higher rates of viral shedding than teenagers.

Why Socialization Patterns Matter

The findings may be explained by the fact that young children and teenagers have very different ways of socializing. “Teenagers engage more physically with friends and schoolmates outside the family and younger children are more engaged with parents and caregivers within,” says Carol Winner, MPH, public health expert and founder of social distancing brand Give Space. “Teenagers tend to be more independent and spend more times alone in their rooms on the phone or computer,” adds Charles Bailey, MD, medical director for infection prevention at Providence St. Joseph Hospital and Providence Mission Hospital in Orange County, California. “Generally, they don’t share in as many ‘family moments’ as when they were younger, preferring instead activities with their peers (including fewer meals at home and spending less time there in general).” Of course, there may be more complex biologic or immunologic factors to explain the observations, and further research is required in those areas. “Whatever those factors may be, it would be hard to control for the sociologic factors listed above,” notes Dr. Bailey. Plus, when it comes to spreading the disease within the household, infected teenagers can isolate whereas young children need continued, hands-on care, says Winner. 

Preventing Spread of COVID-19 at Home

“The best preventive measure to protect children from COVID-19 is for children aged 12 to 17 to receive the vaccine to minimize infection and subsequent likelihood of household transmission,” says Winner. Within the home, regular hand-washing before and after interacting with children (including wiping their noses), mask-wearing, and physical distancing when age-appropriate will help to reduce the spread of disease. These are important measures whether your child is infected or not. What you do outside of the home can also make a difference. “With pediatric admissions at an all-time-high, safety measures outside the home should include keeping friend and extended family activities to a minimum, encouraging outdoor playtime, and saving any family getaways for safer times,” advises Winner.

Young children may not understand the importance of these measures and need your assistance to wash their hands, wear a mask, or more. But teenagers are old enough to know what to do, so passing the right messages to them is a crucial part of the fight against COVID-19.