A Virus Outbreak Has Killed 11 Children at a New Jersey Health Center. Here’s What to Know

A viral respiratory illness outbreak has killed 11 children and infected 23 others at a medical facility in New Jersey, state health officials confirmed.

The New Jersey Department of Health initially announced that 18 cases of adenovirus, six of them fatal, had been confirmed among pediatric residents at the Wanaque Center for Nursing and Rehabilitation in Haskell. On Friday, officials announced that the case count has risen to 34, and 11 children have died. A Wanaque staff member also became sick but recovered.

The affected “medically fragile” pediatric patients, some of whom had respiratory problems before the outbreak began, range in age from toddlers to young adults, though the “vast majority” are younger than 18, according to the Department of Health. An investigation is ongoing, but the center has agreed not to admit new patients until the outbreak is deemed over.

New Jersey Governor Phil Murphy said in a statement that state and local health officials are working to contain the outbreak.

“I am heartbroken by the news that several children have lost their lives in an adenovirus outbreak at the Wanaque Center for Nursing and Rehabilitation, and pray for the full recovery of the other children impacted,” Murphy said. “I have been briefed by [Commissioner of Health] Dr. Elnahal, who has assured me that the Department of Health has recommended vital measures to enhance protections against the further spread of infection and will continue its active on-site surveillance.”

Here’s what to know about adenovirus and the outbreak in New Jersey.

What is adenovirus?

The various strains of adenovirus can cause a variety of illnesses, ranging from common colds to neurologic conditions, according to the Centers for Disease Control and Prevention (CDC). Illnesses resulting from this family of viruses are usually fairly minor, although certain strains can cause more severe sicknesses. Adenovirus 7, the strain health officials said is behind the New Jersey outbreak, is commonly associated with respiratory diseases, though it’s also been linked to fevers and conjunctivitis (pink eye), according to the CDC.

The viruses can be spread through close personal contact, coughing and sneezing or touching contaminated objects. Some strains can also be spread through water that an infected person has been in or through stool, the CDC says.

What’s behind the New Jersey outbreak?

Wanaque is a residential facility that cares for “medically fragile” newborns, children and young adults, as well as elderly individuals and those requiring rehabilitation. These patients’ preexisting health issues, as well as their shared environment, may have facilitated the spread of adenovirus, according to the state health department.

“Unfortunately, the particular strain of adenovirus (#7) in this outbreak is affecting medically fragile children with severely compromised immune systems,” the New Jersey Department of Health said in a statement. “The strain has been particularly associated with disease in communal living arrangements and can be more severe.” Those with weakened immune systems may also carry and transmit the virus after they have recovered from an illness, the CDC says.

What are other risks of adenovirus outbreaks?

Adenoviruses can cause a variety of illnesses on their own, but the infections are also connected to another pediatric condition in the news: acute flaccid myelitis (AFM), a polio-like illness that can cause muscle weakness, paralysis and even death. It’s often difficult to prove what causes AFM, but it can follow adenoviruses, as well as poliovirus, enteroviruses and West Nile virus, the CDC says. The CDC is currently investigating an uptick in AFM cases, with 72 diagnoses confirmed so far this year in 24 states, including New Jersey.

What’s known about Wanaque Center for Nursing and Rehabilitation?

Wanaque Administrator Rowena Bautista said in a statement provided to TIME that the facility is cooperating with local and national health authorities to stem the spread of disease.

“The facility promptly notified all appropriate government agencies when the virus was initially identified, including the New Jersey Department of Health, the Passaic County Department of Health, the Communicable Disease Service and the Centers for Disease Control,” the statement says. “The Wanaque Center continues to fully cooperate with these agencies and has sought out their medical guidance with respect to the virus. 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.”

A surprise inspection in October revealed that Wanaque “failed to ensure hand hygiene was performed according to facility policy and acceptable standards of infection control practice.” A report resulting from that investigation said that the facility “must establish and maintain an infection prevention and control program” that includes systems for “preventing, identifying, reporting, investigating, and controlling infections and communicable diseases for all residents.”

Unrelated Medicare investigations in 2017 and 2016 also found “infection control” issues at Wanaque, including failing to properly clean and disinfect surfaces and objects inside the facility, improper storage of syringes and other tools and inadequate hand-washing practices.

Wanaque was also one of the subjects of a $50 million lawsuit earlier this year, when the estate of a 75-year-old Alzheimer’s patient accused staff at the facility, as well as local police, of negligence and recklessness, NorthJersey.com reports.

Could more people get sick?

While health officials are working to contain the outbreak, they have warned that adenovirus symptoms can appear as long as two weeks after virus exposure. The Wanaque patients who are currently ill got sick between Sept. 26 and Nov. 12, so it’s possible that more cases will arise. Wanaque will not admit new patients until the outbreak is declared over — four weeks after the last illness onset — to contain infections.

With cases still emerging, the Department of Health on Thursday called on members of the New Jersey Medical Reserve Corp. to help the facility quarantine sick children from those unaffected by adenovirus. That effort must be complete by Wednesday. Wanaque will also be required to hire an infection control practitioner, the Department of Health said.

Elsewhere in New Jersey, health officials confirmed that four patients at Voorhees Pediatric Facility, about 100 miles south of Wanaque, have become infected with a separate strain of adenovirus. The two cases do not seem to be related, and health officials said illnesses at Voorhees do not seem to be as serious as those at Wanaque.

“The pediatric patients in Voorhees do not have the severity of illnesses we’re seeing among residents at the Wanaque Center for Nursing and Rehabilitation,” Elnahal said in a statement. “While we cannot release private medical information, these patients in Voorhees are not in critical condition.”

In an effort to prevent similar outbreaks in the future, the New Jersey Department of Health sent a team of infection control experts and epidemiologists to Newark’s University Hospital and four long-term pediatric care facilities — Wanaque, Voorhees and Children’s Specialized Hospital in Toms River and Mountainside — to educate staff on proper procedures. “Facility outbreaks are not always preventable, but in response to what we have seen in Wanaque, we are taking aggressive steps to minimize the chance they occur among the most vulnerable patients in New Jersey,” Elnahal said in a statement.