Children are at extremely slim risk of dying from Covid-19, according to some of the most comprehensive studies to date, which indicate the threat might be even lower than previously thought.

Some 99.995% of the 469,982 children in England who were infected during the year examined by researchers survived, one study found.

In fact, there were fewer deaths among children due to the virus than initially suspected. Among the 61 child deaths linked to a positive Covid-19 test in England, 25 were actually caused by the illness, the study found.

The three studies, by researchers in the U.K. reviewing its national health system’s medical records or pulling together data from other countries, were published on preprint servers Thursday. The studies haven’t yet been reviewed by independent experts and are preliminary.

The studies provide some of the most detailed analysis yet of severe illness and death from Covid-19 in children, a closely watched subject as schools prepare for a new academic year and parents weigh whether to have their children vaccinated if shots are cleared for younger ages. One of the studies focused only on deaths, while the other two examined the risks of severe illness and death.

Researchers previously had found the risk of severe illness and death from Covid-19 among children under 18 years was relatively low. The new studies confirm the findings, adding to the weight of evidence as policymakers and school officials make decisions about mask-wearing and physical distancing.

“Having a larger and larger database…adds a lot to our ability to make important decisions,” said Dr. Rick Malley, an infectious-diseases specialist at Boston Children’s Hospital and Harvard Medical School, who wasn’t involved in the studies. The study examining the risk of death is “certainly one of the largest studies I’ve seen,” he said.