Norovirus Outbreak Can Spread to EMTs and Paramedics

Staff at a local assisted living facility begins to notice increased incidence of vomiting, nausea and diarrhea among its residents. ALS ambulances are called to transport seven patients, with several other BLS transports completed by private ambulance companies.

Your partner participates in four separate patient transports from the facility. Two of these patients are actively vomiting, a third is complaining of abdominal pain without vomiting, and a fourth suffered a ground-level fall. The vomiting patient is unable to ambulate to the stretcher and is lifted with cross-chest method, so your partner’s face, nose and mouth were in close proximity to the patient.

She wears gloves during all patient care activities, utilizes hand sanitizer gel upon glove removal, and performs handwashing with soap and water after the patients are transferred to the receiving ED. The distance from the patient’s home to the receiving facility is approximately two miles, resulting in less than 10 minutes of transport time.

That evening, the local health department is notified of a potential virus outbreak and begins investigating.

Two days later, your agency receives official notification from the local health department that an outbreak of gastrointestinal (GI) illness was underway at the assisted living facility, with a presumption that norovirus was the causative agent. Initial cultures for common GI pathogens are negative.

That same day, your partner begins to experience nausea and vomiting. She describes it as “the worst case of puking I’ve ever had.” The infection control officer makes contact with her the next day, but doesn’t feel that medical care is necessary. Your partner presumes the symptoms are caused by norovirus. Because of the high likelihood of transmission if your partner reports to the occupational health clinic, her hesitancy to travel away from bathroom facilities, and the lack of urgent need for medical intervention, the infection control officer recommends your partner stay at home until symptoms resolve. She should, however, seek immediate medical care if her condition deteriorates.

Collaborative efforts with the local receiving facility, the county health department, and infectious disease doctors are unable to obtain a positive culture for norovirus from any of the initial six patients cultured. However, a positive fecal culture from a resident of the assisted living facility, transported by another ambulance a week later, is obtained by the local receiving facility and deemed consistent with the reported history.

The infection control officer determines your partner’s symptoms were most likely contracted while providing patient care and met the following criteria for an occupationally-acquired illness:

  • Known exposure: She had contact with more than one patient from the facility, and two patients were actively experiencing symptoms and able to transmit virus via the airborne route;
  • Lack of protection: At the time of exposure, she had no information available to indicate the need for masking or use of personal protective equipment (PPE) above that of standard precautions and, therefore, wasn’t wearing a mask while providing care; and
  • Temporal relationship: The timing of the onset of her symptoms was consistent with the incubation period for norovirus.

Your partner was most likely exposed to norovirus while lifting the vomiting patient. Norovirus can spread through aerosolized vomit that lands on a surface or enters a person’s mouth and is then swallowed. This type of transmission can be effectively prevented through the use of surgical mask or by keeping a distance of 4—6 feet from the patient. There’s no evidence that norovirus can be spread through inhaling the virus; therefore it isn’t spread by the airborne route and doesn’t require the use of N95 masks. She’s deemed noninfectious and cleared to return to duty after four days.


The norovirus pathogen is the most common cause of acute gastroenteritis and is often implicated in outbreaks in the community and healthcare setting.1 Symptoms caused by infection with norovirus include fever, nausea, vomiting, cramping, malaise and diarrhea, lasting 2—5 days. In more serious cases of illness, patients may experience hypovolemia and electrolyte imbalance, as well as hypokalemia and renal insufficiency.1

Although commonly known for causing outbreaks on cruise ships, the impact of norovirus infection is much more widespread. It’s estimated that norovirus is responsible for 23 million gastroenteritis cases each year in the United States, resulting in over 91,000 ED visits and 23,000 hospitalizations for severe diarrhea among children under the age of 5 each year.1 From 2009 to 2013, 78% (n = 3,215) of acute gastroenteritis (AGE) outbreaks with a laboratory-identified agent were attributed to norovirus, as were 58% (n = 6,223) of AGE with a suspected pathogen.2

Individuals infected with norovirus only have transient immunity to the pathogen, which is strain-specific (i.e., immunity is only for the same strain as the initial infecting agent). There’s no vaccine for norovirus and medical treatment is typically supportive in nature (e.g., fluid replacement). Because norovirus has a very low infectious dose
(< 10—100 virions), a short incubation period (24—48 hours), and survives well in the environment, it can spread rapidly through confined populations.1

In the institutional setting, such as hospitals and long-term care facilities (LTCFs), the pathogen may be brought into the facility through ill patients, visitors, healthcare workers or other staff. Transmission of the virus typically occurs by direct or indirect fecal contamination found on inanimate objects such as handrails and stethoscopes, ingestion of contaminated food and water, or aerosolized norovirus from vomiting persons.1

Norovirus infection causes a significant burden of illness among the elderly, including more severe outcomes and longer duration of illness than in the general population.1 LTCFs incur the vast majority of AGE outbreaks. From 2009—2013, 70% of reported AGE outbreaks occurred in LTCFs, 8% occurred in schools, 7% occurred in childcare facilities, and 4% occurred in hospitals.2

The case study presented here underscores the risk to EMS personnel when transporting patients in the outbreak setting, including a risk of transmission through aerosolized vomitus. The use of gloves and performance of appropriate hand hygiene doesn’t completely mitigate this risk.


EMS personnel should maintain a high index of suspicion for norovirus when treating and transporting patients with nausea, vomiting and diarrhea from high-risk environments or when a known outbreak is occurring in the community. These high-risk environments include hospitals, LTCFs, day care centers, prisons, military installations or other institutions where communal living occurs.

In these instances, EMS personnel should use surgical masks and gloves, at minimum–along with gowns or other PPE to maintain contact precautions. The Centers for Disease Control (CDC) recommends use of a surgical or procedure mask and eye protection or a full face shield if there’s an anticipated risk of splashes to the face during the care of patients, particularly among those who are vomiting.1

Departments should provide, and employees routinely use, FDA-compliant ethanol-based hand sanitizers (60—95% ethanol content). Hand sanitizers with other alcohol components or non-alcohol active ingredients are less effective against the norovirus pathogen.1

The CDC also recommends use of soap and water for hand hygiene after providing care or having contact with patients suspected of having norovirus gastroenteritis, particularly in the context of an outbreak.1 This should also be done after removing gloves.

Departments should implement a system to identify potential cases of norovirus and to notify receiving facilities prior to arrival with the patient so that appropriate isolation precautions can be taken. Equipment shared between patients, such as blood pressure cuffs, should be cleaned with an Environmental Protection Agency-registered product with label claims for use in healthcare.1,3 The manufacturer’s recommendations for application and contact times should be followed. The stretcher and patient care area of the ambulance should be disinfected between patients.

If the item is visibly soiled, it should be cleaned of debris prior to application of disinfectant. When handling soiled linens, avoid agitating them to avoid dispersal of the virus.1 Use appropriate PPE (i.e., masks, gloves, gowns) and fold linen inward when removing from the stretcher, in order to minimize cross-contamination.

In the context of a suspected norovirus outbreak, the CDC recommends exclusion of ill personnel from work for a minimum of 48 hours after resolution of symptoms.1

Crews should receive annual education about the appropriate use of PPE when a patient is actively vomiting, including mask and eye protection. Once an outbreak is detected, education should be provided to crews, including recognition of symptoms and prevention strategies, as well as steps to take if a work-related exposure is suspected.

Fire departments and EMS agencies should also work closely with local health departments, as well as administration at local facilities, to develop written policies for timely notification when an outbreak is suspected.


All of these recommendations are effective infection control and prevention strategies for other forms of infectious AGE. Maintaining a high index of suspicion and an appropriate respect for the potential burden of illness caused by norovirus provide an opportunity to implement appropriate prevention strategies to maintain the health of EMS personnel.


1. MacCannell T, Umscheid CA, Agarwal RK, et al. Guideline for prevention and control of norovirus gastroenteritis outbreak in healthcare settings. CDC. Retrieved Jan. 11, 2015, from

2. Wikswo ME, Kambhampati A, Shioda K, et al. Outbreaks of acute gastroenteritis transmitted by person-to-person contact, environmental contamination, and unknown modes of transmission. MMWR. 2011;64(SS12);1—16.

3. U.S. Environmental Protection Agency. (March 14, 2016.) Selected EPA-registered disinfectants. Retrieved Jan. 11, 2015, from

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