NEW HAVEN, Conn. (WTNH) — New scientific data reveals that children can have the COVID-19 virus without knowing they have it, allowing them to then easily spread it to others.

According to the American Medical Association, 75% of children with COVID-19 do not show symptoms, which can be a reason why adults — including those at high risk or the elderly — may not think being around them could pose a risk.

“What we think is that those who are younger are in closer contact, more prolonged contact with other family members,” aid Dr. Richard Martinello, a pediatric infectious disease physician with Yale Medicine.

The AMA study reveals that schools have the highest public source of exposure compared with health clinics and grocery stores.

And while anyone can get multiple viruses at once, children, especially young kids appear to be much more likely.

A study in the Journal Pediatrics of more than 4,000 children hospitalized found those with multiple infections were more likely to require oxygen and need intensive care.

“The the best thing one can do is to make sure you’re vaccinated,” Martinello said. “Wear masks to protect yourself and make sure that you’re washing your hands.”

There is now more proof that COVID-19 is the most dangerous in older adults, making up 90% of COVID-19 deaths in recent weeks. Martinello said seniors should seek the oral treatment Paxlovid.

“It’s very helpful to keep those who have risk factors for more severe COVID, to keep themselves out of the hospital and frankly, to keep from dying, too,” he said.

There is positive news now on a vaccine for RSV, with Moderna revealing its vaccine has 84% effectiveness at preventing serious illness, according to data from a late-stage trial published Tuesday.

The vaccine would also benefit young children who can also become extremely ill with RSV.

Other drug companies are also working on an RSV vaccine.