June 06, 2017
4 min read

CDC: Health care-associated Legionnaires’ disease widespread in US

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A recent CDC analysis including data from 20 states and New York City showed that 76% of these jurisdictions reported cases of health care-associated Legionnaires’ disease, which the CDC said is “a concerning finding” given that the disease is particularly severe when acquired in such settings.

Cynthia G. Whitney, MD, of CDC’s Division of Bacterial Diseases and National Center of Immunization and Respiratory Diseases, and colleagues, found that health care-associated Legionnaires’ disease is associated with a 25% mortality rate. In contrast, they reported that the disease is usually associated with an estimated 9% mortality rate.

Anne Schuchat
Anne Schuchat

“At CDC, we take patient safety very seriously,” Anne Schuchat, MD, acting director of the CDC, said during a press conference today. “We already focus on a number of strategies such as hand hygiene and antibiotic stewardship to protect patients from health care-associated infections, but having a water management program needs to be added to that list.”

According to Schuchat, Legionnaires’ disease is a type of deadly lung infection that is contracted through inhalation of contaminated water droplets. Sources of contaminated water, she added, may include shower heads, water therapy spas and baths, cooling towers, decorative fountains and certain medical devices such as respiratory therapy equipment. Because symptoms of Legionnaires’ disease — which include coughing, shortness of breath, fever, muscle aches and headache — are similar to other kinds of pneumonia, Whitney said during the press conference that it is essential for health care providers to order tests specifically for Legionella.

“It’s important to note that most healthy people do not get Legionnaires’ disease after being exposed to Legionella,” Schuchat said. “People with greater risk are 50 years of age or older, current or former smokers, and those with chronic diseases or weakened immune systems. In health care facilities, people are most vulnerable because they are already sick.”

For the analysis, Whitney and colleagues examined national surveillance data collected from 20 U.S. states (Alabama, Colorado, Connecticut, Georgia, Hawaii, Iowa, Kentucky, Maine, Michigan, Minnesota, Missouri, New Hampshire, New Mexico, New York, North Dakota, Ohio, Rhode Island, South Carolina, Texas and Virginia) and New York City in 2015. They assessed for definite cases of health care-associated Legionnaires’ disease — defined as patients who stayed in a facility for 10 days before developing symptoms — as well as possible health-care associated cases — defined as patients who stayed in a facility for some portion of the 10 days before developing symptoms.

More than 2,800 confirmed cases of Legionnaires’ disease were identified, including 85 definite and 468 possible health care-associated infections. Among the 21 jurisdictions, 16 (76%) reported definite health care-associated cases in 72 different facilities. The number of these cases ranged from one to six per facility, Schuchat said. The majority were associated with long-term care facilities (80%), followed by hospitals (18%) and both a long-term care facility and a hospital (2%).

The possible health care-associated cases were reported in about 415 different facilities, Schuchat said. Among them, 13% were associated with long-term care facilities, 49% with hospitals, and 26% with outpatient clinics.


Overall, definite cases of health care-associated Legionnaires’ disease accounted for 3% of all cases. Meanwhile, probable health care-associated Legionnaires’ disease accounted for one in five cases, which Schuchat said likely reflects the actual proportion of health care-associated cases vs. non–health care-associated cases.

“The reality of underdiagnoses, underreporting and the complexity of pinpointing a source of Legionnaires’ disease given the long incubation period makes it very likely that many people who are diagnosed with Legionnaires’ disease after a hospital stay probably got that infection while they were in the hospital,” she said. “I think our experts feel that one in five is a lot closer to reality than 3%.”

Last year, the CDC reported that the number of Legionnaires’ disease cases had quadrupled in the U.S. from 2000 to 2014. In response, the CDC launched a toolkit, “Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards,” that building owners and managers and public health officials can use to improve water management systems. The guidance is a simpler interpretation of ASHRAE Standard 188, a document that sets industrial standards for building engineers. It provides a checklist that will help those working in building safety to identify areas where Legionella can grow and ways to reduce contamination risks.

During the press conference, Schuchat acknowledged that implementing the toolkit is a “big culture change” for hospitals and infection control practitioners.

“We had tremendous uptake of improving our use of antibiotics and improvements in health care-associated infection prevention through handwashing and other processes, but most infection control practitioners haven’t even heard that Legionnaires’ disease can be a hospital-acquired infection,” she said.

However, she added that the Centers for Medicare & Medicaid Services (CMS) recently announced that facilities are now expected to implement policies and procedures designed to reduce the risk of Legionella and other pathogens in water. According to previous analyses, insurers pay an estimated $434 million in hospitalization claims for Legionnaires’ disease each year in the U.S, Schuchat said. The total cost for each patient is approximately $38,000.

“The CMS guidance is very important ... because when hospitals are visited, this will be one of the many things that will be checked consistently,” she said. “So, this is essentially a warning to health care facilities: if you don’t have a good water management plan, this is the time to study up and develop one.” – by Stephanie Viguers


CDC. Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards. 2016. https://www.cdc.gov/legionella/downloads/toolkit.pdf Accessed June 6, 2017.

Soda EA, et al. MMWR Morb Mortal Wkly Rep. 2017;doi:10.15585/mmwr.mm6622e1.

Disclosures: Schuchat and Whitney report no relevant financial disclosures.