New Jersey health officials said Thursday tests confirmed a 19th patient has been infected in a viral outbreak at a pediatric rehabilitation center that has killed seven people.

The unidentified person had already been ill so the diagnosis does not necessarily mean the virus is still spreading, according to Health Department spokeswoman Donna Leusner.

The outbreak won’t be declared over until the Wanaque Center for Nursing and Rehabilitation can go four weeks without any new cases of people being infected with a type of germ called adenovirus 7, Health Commissioner Dr. Shereef Elnahal said this week .

The seven who died this month were children and at least one young adult, all in a respiratory unit where patients receive long-term help with breathing.

Adenovirus usually poses little risk for healthy people and typically causes mild cold or flu symptoms, including sore throats, fever, coughs and sneezes. Some strains also cause diarrhea and or pinkeye.

The strain found in the rehab center outbreak is among the more potent types. It sometimes causes more serious respiratory illness, especially among those with weak immune systems.

Many of the children at the facility require ventilators for breathing, and some have spent all or most of their lives there, the commissioner said. He described the patients as “fragile.”

It’s unlikely that there’s a broader threat, he said.

Health officials said they have teams at the facility monitoring the infection, and the center has closed to new patients.

The 227-bed for-profit facility has a pediatric center and also cares for elderly residents.

The identities of those who died and the affected patients have not been disclosed.

(AP)