All but one are children with a weakened immune system and other serious medical problems, many of which need help to breathe and work at the Wanaque Nursing and Rehabilitation Center in Haskell, New Jersey.
Confirmed cases fell between September 26 and November 5, according to the health department. The number increased from 18 cases, including six deaths, announced last month by the health department.
An employee was also influenced by the outbreak, but has recovered.
The outbreak of Wanaque was caused by adenovirus type 7. This type is "most commonly associated with acute respiratory disease," according to the US Centers for Disease Control and Prevention. Other types of adenovirus infections can cause flu-like symptoms, pinkeye and diarrhea.
The health department also announced on Monday that a new adenovirus case was found in children at a second facility in New Jersey, the Voorhees Pediatric Facility – reaching their total of five. However, CDC tests suggest that the culprit is a type 3 adenovirus, a strain different from that of Wanaque.
Patients in the Voorhees unit were ill between October 20 and 29. Control by the state health department last week did not detect infection control problems and did not publish reports.
"The Department and local health partners have worked with the facility to provide recommendations for the control of infections and the identification of other possible diseases since then [Voorhees] announced to the Department a case of adenovirus to a resident on October 26, said in a statement Monday, New Jersey's health minister, Shereef Elnahal.
Health officials say they are stepping up efforts to strengthen the control of infections in such facilities in the state. The health department announced plans last week to develop an expert group on infection control to visit the University Hospital and four pediatric long-term care facilities this month, including the Wanaque and Voorhees facilities, where experts will train staff and assess how these facilities prevent and control infections.
"Abandonment cases can not always be prevented, but in response to what we have seen in Wanaque, we take aggressive steps to minimize the likelihood of appearing among the most vulnerable patients in New Jersey," Elnahal said in a statement last week.
Adenoviruses often spread by touching an infected person or surface or through air with coughing or sneezing. They are known to insist on impure surfaces and medical instruments for long periods of time and can not be removed from common disinfectants but rarely cause serious illnesses to healthy people. However, people with a weakened immune system are at greater risk for serious illness and can remain contagious long after their recovery, according to the CDC.
Symptoms may occur two to 14 days after exposure to the virus, the State Health Department said.
Infections and deaths come amid questions – from the former employees of Wanaque Center, the mother of one of the children who died and Elnahal himself – about whether the current plant standards are high enough and whether more could be done to avoid this.
Elnahal previously said in a statement that the findings of a recent surprise health inspection at the Wanaque unit "raise questions as to whether these generic long-term care models are the best for this vulnerable population of medically fragile children."
"We also need to think if there is more we can do as health care leaders to protect immunosuppressed children, such as those served at the Wanaque Center," he said. "Every year in the state, there are hundreds of outbreaks in healthcare facilities."
In statements last month, the Wanaque facility said he was working with health experts to investigate the outbreak and that he "immediately alerted all relevant government agencies when the virus was first detected." According to State Health Service Representative Nicole Kirgan, health officials were informed of the respiratory illness at the premises of October 9 and the facility notified their parents 10 days later on October 19th.
The installation did not respond to CNN calls and messages for further comments.
The facility is "instructed not to admit new patients until the outbreak is complete and is in full compliance," according to the State Health Department. State healthcare officials have said that the epidemic can only be reported when four weeks have elapsed without an extra case.
"It may be difficult to be impossible to know how the virus arrived at the facility, what its source was or what is the specific mechanism of its spreading from person to person," Elnahal said.
CNN's Evan Simko-Bednarski contributed to this report.