While there is a vaccine against the strain that killed the children, it is only available to the US military and not available to the general public, according to the Centres for Disease Control and Prevention (CDC).
A vaccine for adenovirus type 7 — the strain in the New Jersey outbreak — was approved by the US Food and Drug Administration in 2011 “for use only in US military personnel who may be at higher risk for infection”, but is not recommended in children under the age of 17, according to the CDC website.
There have been 18 cases of adenovirus at the Wanaque Centre for Nursing and Rehabilitation in Haskell, which has affected “medically fragile” children with severely compromised immune systems, according to the Health Department.
The six deaths happened this month, according to New Jersey Health Department spokeswoman Donna Leusner.
The Health Department did not release the ages of the victims or address the severity of the illness in the other dozen cases.
In New Jersey, a team was at the centre Tuesday and Sunday and found “minor handwashing deficiencies,” the Health Department said.
“The Health Department is continuing to work closely with the facility on infection control issues,” the department said in a statement.
The CDC said in an email that it is providing technical assistance to the state.
The strain afflicting the children is usually associated with acute respiratory illness, according to the CDC.
Dr William Schaffner, an infectious disease professor at Vanderbilt University Medical Centre, said these kinds of fatalities are not common, but they’re known to happen.
“Here I think you have this kind of nasty combination of very fragile children and this particularly aggressive virus,” he said.
Governor Phil Murphy said in a statement that he was “heartbroken” about the deaths and that he had been briefed by the health commissioner, Dr Shereef Elnahal, who told him that the department was on site and trying to prevent the virus from spreading further.
“I am confident that the steps being taken by state and local officials will minimise the impact to all those who remain at the facility,” Governor Murphy said.
In the past 10 years, cases of severe illness and death from the type of infection found at the facility have been reported in the United States, said CDC spokeswoman Kate Fowlie in an email, though it is unclear how many deaths there have been.
The facility was instructed not to admit new patients until the outbreak ends, and the Health Department said the number of new cases appeared to be decreasing.
Adenoviruses often cause mild illness, particularly in young children, but people with weakened immune systems are at risk of getting severely sick, according to the CDC.