The Wanaque Center for Nursing and Rehabilitation, located in Haskell, has been instructed by the state's health department not to admit any new patients until the outbreak has ended.
A team from the health department were on hand at the center Tuesday to investigate.
Officials at the Wanaque Center earlier confirmed "some cases" of the virus were found in its pediatric unit. "This outbreak is affecting medically fragile children with severely compromised immune systems", the statement said. "As a result, facility staff have diligently implemented all available infection control and prevention measures in order to protect the health and safety of the Wanaque Center's residents".
The facility's paediatrics centre serves newborns to 22-year-olds who are "medically fragile" and provides an individualized program for each child, the centre's website said.
The Health Department didn't release the ages of the victims or address the severity of the illness in the other dozen cases.
"It can cause pretty much like a common cold type of illness in the majority of the population", Javaid said, adding that if someone's immune system is compromised a minor cold can turn into something much worse.More news: Liberals play blame game over Wentworth loss
This strain is associated with disease in communal living facilities, the officials said.
New Jersey Gov. Phil Murphy issued a statement, saying he was "heartbroken" over the deaths.
The department had reportedly been notified by the 227-bed facility of cases of respiratory illness on October 9.
It also offers an adult nursing home and rehabilitation center for either short-term or long-term care.
An inspection team from the state health department responded to the facility on Sunday and another team from the agency returned to the center on Tuesday. Symptoms usually include sore throats, pneumonia, diarrhea and pink eye.