At least six "medically fragile" children died in an outbreak of adenovirus at a New Jersey hospital for young patients with "severely compromised immune systems".

Adenovirus isn't usually deadly; it causes cold or flu-like symptoms.  Usually, people can protect themselves from adenovirus by washing their hands, avoiding touching their faces, and limiting contact with infected individuals - the usual "avoid the flu" stuff.  The #7 strain can lead to pneumonia, and that can be deadly without treatment.

But this one raced through the Wanaque Center for Nursing and Rehabilitation in Haskell, according to a statement from the New Jersey Department of Health.  Officials said the childrens' condition made them more susceptible to infection.

"The combination of a worse strain of adenovirus together with a fragile population has led to a more severe outbreak," read a statement.  "The facility has been instructed to not admit any new patients until the outbreak ends and they are in full compliance."

It's unclear exactly how the New Jersey outbreak started, but an investigation by the Health Department found "minor handwashing deficiencies" at the private hospital.