Babies and toddlers are faster Covid spreaders than teens in the home, study finds

This is most likely due to behavioural differences in each age group.

Though babies and toddlers are less likely to bring coronavirus into the home, they're more likely to spread it once it's in the home, according to a new study. The study, conducted in Ontario, Canada from June 1 to December 31, 2020, examined 6,280 Covid-positive households in which the first person to catch the virus was under 18.

Researchers then looked at secondary cases or others in the household who got sick within two weeks of the first child falling ill.

The findings showed the chain of transmission stopped with the infected child in most cases, but in 27.3% of households, children passed the virus to at least one other resident. Teens were more likely to bring the virus into the household, with 38% of index cases being children aged 14-17. Children aged 3 or younger were the index cases in just 12% of households, but they were the group who most frequently infected another resident. This is most likely due to the behaviours of each age group. "When we think about what's teen social behaviour outside of the house, they're spending a lot of time together, they're often in quite close quarters, they're often touching or sharing a drink," Dr. Susan E. Coffin, an infectious disease specialist uninvolved in the study, told the New York Times. Their social life and education could thereby make them more likely to contract the virus and bring it into the home. Younger children and infants have less external social interaction, but are more likely to be in their parents arms or touch objects and surfaces (be it with their fingers or their tongue!) as they explore. "Once they bring it into the household, it can be spread easily," Dr. Coffin added.

Other studies have found that though young children rarely get seriously ill from the virus, they may carry higher levels of virus or have higher rates of viral shedding than teenagers.

However, disease transmission dynamics are complicated, so the exact role children of all ages play in the spread of Covid-19 remains unclear.