Babies and toddlers may be more likely to transmit the virus that causes COVID-19 within households compared to teenagers, according to a new study.

The study, published in the journal JAMA Pediatrics on Monday, analysed publish health data from Ontario, Canada, to identify Covid clusters in which a child was the primary case within households.

So, while younger children are less likely to bring the coronavirus into their homes than teenagers, they are more likely to spread it once they are infected. This is probably because babies and toddlers are cared for directly by parents and caregivers, in close contact, researchers said.

Earlier in the pandemic, some scientists thought that children were less likely to get infected with the virus, to spread it and to fall sick. But those assumptions were likely skewed by the fact that lockdowns and social distancing meant less social interactions.

The new population-based cohort study took place between 1 June and 31 December, 2020, in Ontario, Canada.

The researchers identified all positive tests associated with private households and then identified the “index case” — the first person to develop COVID-19 symptoms or test positive for the virus — in each household, NYT reported.

The study focused on 6,280 households in which the first person to catch the virus was under 18.

The researchers they looked for secondary cases, or others in the same home who got sick in the two weeks after the first child fell ill.

Children aged 0 to 3 years had the highest odds of transmitting SARS-CoV-2 to household contacts compared with children aged 14 to 17 years.

Children aged 4 to 8 years and 9 to 13 years also had increased odds of transmission.

The odds of household transmission were roughly 40 percent higher when the infected child was 3 or younger than when they were 14-17.

However, the study doesn't mean that very young children are more likely to die if infected with the virus. But they may be more likely to transmit the virus than previously thought.

(With inputs from The New York Times.)