More than 70 percent of schoolchildren in Japan feel stress as a result of the spread of the coronavirus, according to a survey by a state-run medical institute.

In response to a survey allowing multiple answers, 72 percent of elementary, junior high and senior high school students said thinking about the virus made them feel bad or affected their concentration, according to the National Center for Child Health and Development.

Nine percent of respondents, meanwhile, reported sometimes hurting themselves or using violence against family members or pets.

The survey also found that 32 percent would not wish it to be known if they or their family members become infected with the virus, while 47 percent believe most people would wish to keep it a secret.

Twenty-two percent said they would not want to play or hang out with those who have contracted the virus, even once they recover.

The center, a major hospital specializing in pediatrics, perinatal care, obstetrics and maternal medicine, conducted the online survey from June 15 to July 26 to examine the impact the pandemic has had on children.

It collected answers from a total of 6,772 people — 981 children aged between 7 and 17, as well as 5,791 adults who have children 17 years old or younger.

Commenting on the results, Mayumi Hangai, a pediatrician and researcher at the center, said parents should let children express their feelings freely rather than scolding them for being irritated, using violence or taking other actions.

"Because it is natural that children get irritated (amid the virus's spread), parents should understand that such feelings come from stress," Hangai said. "Parents' understanding would be the best way to reduce children's stress."