As the school year has started in many countries with restrictions amid the COVID-19 pandemic, like wearing face masks and keeping social distance, parents are trying to figure if it is safe for their children to attend school.

Some countries made it obligatory for kids to wear face masks while in school, but, the question is, can kids be harmed by wearing masks almost all day?

The answer is no, there is no scientific evidence showing masks cause harm to kids’ health despite baseless claims suggesting otherwise.

The claims are circulating on social media and elsewhere just as virus outbreaks are hitting many reopened U.S. schools – particularly those without mask mandates.

Among the unfounded arguments: Masks can foster germs if they become moist or cause unhealthy levels of carbon dioxide. But experts say washing masks routinely keeps them safe and clean.

Some argue that young children miss important visual and social cues that enhance learning and development when their classmates and teachers are wearing masks. But others note that children with vision or hearing impairment learn to adapt and that other kids can, too.

“We don’t know for sure that masks have no developmental effects but we do know that there are adverse effects from not trying to stop transmission,” said Dr. Emily Levy, critical care and infection control expert at Mayo Clinic Children’s Center.

There’s strong evidence masking children in schools can reduce COVID-19 transmission to other children and adults.

In the U.S. across 166 schools in Maricopa County, Arizona, COVID-19 outbreaks are two times more common than those without mask mandates, said Dr. Rebecca Sunenshine, medical director of the county’s public health department.

Studies from school districts in other states including North Carolina have also found that masking can greatly reduce COVID-19 transmission rates, especially when it’s combined with physical distancing and other prevention measures.

“One thing that we know about prevention, about infection control is that there isn’t a single intervention that will win the day,” said Dr. Joshua Schaffzin, director of infection prevention and control at Cincinnati Children’s Hospital.

But he noted there’s plenty of evidence that masking is a key component in making schools safer.

To avoid skin irritation, doctors suggest washing masks regularly, making sure they fit properly and picking masks made with soft, breathable fabric.