These steps are in sequential order with the most important being confirming the presence of the outbreak. For convention’s sake, an outbreak can be defined as
an increase over the expected occurrence of an event. Given that measles is a rare event geographically in Hawai‘i, one case can be considered an outbreak.
Confirming the presence of an outbreak
The initial step in the investigation is to confirm that what is being reported indeed represents an increase in the outcome. Nothing should be done until you have scientific evidence, in this case, presence of signs and symptoms of measles and supporting lab tests. Only a physician can diagnose measles, and consulting a pediatrician or infectious disease physician is extremely important for an accurate decision. Your IP and Chair of Infection Control will work together and confirm the diagnosis.
Alerting key partners about the investigation
At the outset of an outbreak investigation, it is critical to inform key partners of the situation. Facility administration should be notified so that resources can be made available and so that risk management and public affairs staff can prepare to assist. In regard to measles, alerting public affairs this early can help communicate news to patients and families, staff, and the reporters. Measles is rare and exciting to put in the news so be sure to watch your local news each night for facts and rumors.
Daily huddles with key stakeholders are essential for clear, effective communication and follow-up of action items. Minimally they should include the infectious disease physician in charge of the outbreak, the IP for your facility, hospital administrators (both inpatient and outpatient), emergency department leadership, laboratory, employee health, public affairs, bed control, security, information technology, supply chain management and risk management. The State Department of Health Epidemiologist must be made aware of your plan for investigation and follow-up. They are responsible for contacting any patient in the public sector; vis-à-vis, not in your hospital at the present time or difficult to reach by phone.
Performing a literature review
There are many reports summarizing outbreak investigations published in the literature, and hence a literature review is a critical early step in any investigation. The literature review will help identify possible sources that might merit further investigation and might also provide important insight into optimal investigative methodology. Another excellent resource for reviewing previous investigations is the Outbreak Worldwide Database (available at http://www.outbreak-database.com). This free database contains summaries of published outbreak reports, including information on the source of the outbreak and control measures implemented to terminate the outbreak.
Establishing a Preliminary Case Definition
The initial case definition should be narrow enough to focus investigative efforts but broad enough to capture the majority of cases. In outbreaks of infectious diseases, the decision on how broad to make the case definition is often driven by the pathogen. In this case, measles may have a broader definition (meaning, just rash and fever) to cast a wide net over suspect cases, with confirmatory testing to follow. This allows for prompt isolation of suspect cases. The physician in charge of the investigation must make this definition.
Developing a Methodology for Case Finding
A variety of sources can be used to find additional cases that might be related to the outbreak. If the case definition includes a laboratory result, laboratory records are a logical place to start and can facilitate rapid identification of possible cases. With measles, the case finding is biphasic: first signs and symptoms are assessed by a physician followed by confirmatory testing performed by the hospital lab and the State Department of Health Disease Investigation Branch. In Hawai‘i, the State Epidemiologist will unleash his/her field team and they collect specimens to be sent to the State Lab.
Preparing an initial line list and epidemic curve
The line list is, arguably, the single most important tool in any outbreak investigation and hence merits considerable early discussion and effort. In general, information that can be helpful on a line list can include details on patient signs or symptoms, or if the patient’s family and primary care physician is aware. This is a living document from the beginning of the investigation through the reporting to your facility’s Infection Control Committee. The IP for your facility is the point person for case documentation and communication to the leadership team and to the Health Department. With measles, hopefully the epidemic curve stops at the index case.
Observing and reviewing potentially implicated patient care activities
In most outbreak investigations, it is the observations of practices that ultimately identify the cause. With measles, this step is important if your facility experiences any secondary cases or failure to recognize and isolate suspect cases. The IP should check all new admissions daily for suspect cases and also round with the Emergency Department staff to ensure early recognition and containment processes are actually working versus solely on paper. Leadership must plan for modification of patient placement if your system is challenged by an influx of the worried well. This issue should be discussed early on and a threshold established.
Considering whether environmental sampling should be performed
Sampling the environment for measles is not indicated. Your facility’s Engineering Department can provide a list of negative pressure rooms and air balancing readings. Before a patient with known or suspected measles is admitted to a negative pressure room, the Engineering Department must check the airflow to determine negative pressure in respect to the hallway or adjacent areas.
Implementing initial control measures
It is important to remember that the ultimate goal of any outbreak investigation is to prevent secondary cases. Thus, it is not only acceptable, but important, to implement a variety of infection prevention measures throughout the course of the investigation. These control measures might be driven by findings from the line list and observations. Measles is very contagious, with a 90% secondary attack rate. The incubation period begins as early as 8 days after exposure, which, given the amount of time it takes to confirm the index case, is a race against time to identify exposed and susceptible patients6.
This is where the rubber meets the road. Your IP and physician in charge of the outbreak are your key players. At this point as hospital administrators and leadership, you must realize all other routine duties required by your IP will be placed on hold. In my 25 years of experience in infection prevention, I can estimate the time interval for measles follow-up to be about 14 calendar days. Additional resources should be considered.
Below is an action list I compiled from our recent exposure in February 2014. Use this as a guide and understand that some points may not be applicable to your facility.
Got Measles? What to do when a measles exposure occurs at your facility.
- Verify the diagnosis. Immediately call the Chair of the Infection Control Committee and discuss the case.
- Locate the patient. If the patient is in the hospital, ensure that he/she is in a negative pressure room on airborne precautions.
- Notify the Department of Health.
- Determine when the patient developed the rash. The rash is the timestamp for calculating incubation periods.
- Contact hospital executive leadership and present known data.
- Identify key stake holders and hold an emergency meeting to discuss plan.
- Determine a time and place to meet minimally once a day to review interventions and facts.
- Compile a list of all exposed patients for each area the patient traveled while in your facility. If you have an EMR then contact the IT Department for assistance.
- Contact employee health and request MMR or immune status of staff working in exposed areas.
- Contact primary care physicians of exposed patients and determine measles immune status. If non-immune suggest social distancing and provide name and number for the Department of Health for additional information.
- Craft three statements describing exposure and risk: one for PCPs, one for families, and one for staff. Public Affairs is expert at this function.
- Identify method to alert PCPs and families. Consider the time interval for the incubation period. Identify any patients exposed who have been admitted each day. Document measles exposure in their record and be mindful that they will need to be placed in negative pressure rooms on airborne precautions during the incubation period. Consider a plan for multiple patients being admitted with known or suspected measles.
- Compile an alphabetical list of exposed and susceptible patients for any area that admits patients (ex. Emergency, clinics, admitting, bed control, pre-surgical clinics). Require that each admitted patient be checked against this list. Any patient considered exposed and susceptible must be placed in a negative pressure room on airborne precautions immediately.
- Plan for an MMR vaccine clinic at your facility if patients need to get vaccine. Work with the Health Department; they may assume this role early on.
- If a hospital MMR vaccine clinic is in your plan, ensure that the pharmacy has enough vaccine on site. Make every attempt to conduct the clinic outside your facility such as a parking lot or adjacent building that is not being used. Consider vaccine storage requirements and needle disposal containers for syringes.
- The IP for your facility should round each day in areas where patients may be admitted (ED, clinics, etc.) to ensure staff can identify suspected measles and place in isolation promptly.
Costs of a Measles Outbreak
In addition to requiring a lot of work, containing a measles outbreak is expensive. A study reviewing the impact of 16 outbreaks in the United States in 2011 concluded that "investigating and responding to measles outbreaks imposes a significant economic burden on local and state health institutions7. Such impact is compounded by the duration of the outbreak and the number of potentially susceptible contacts."
For example, it cost:
- $130,000 to contain a 2011 measles outbreak in Utah
- $24,569 to contain a 2010 measles outbreak in Kentucky
- $800,000 to contain a measles outbreak at two hospitals in Arizona
- $176,980 to contain a 2008 measles outbreak in California
- $167,685 to contain a 2005 measles outbreak in Indiana - unvaccinated 17-year-old catches measles on church mission trip to Romania, leading to 34 people getting sick, including an unvaccinated hospital worker who was on a ventilator for 6 days
- $181,679 (state and local health department costs) to contain a 2004 measles outbreak in Iowa triggered by a unvaccinated college student's trip to India
The 2013 Texas outbreak cost $50,758.93 to contain. With 16 cases of measles in that outbreak, that comes to about $3,100 for each case of measles. And while that may seem like a bargain when you look at some of the other outbreaks, that was only for the direct public health costs to the county health department, including staff hours, the value of volunteer hours, and 240 syringes.
Additional costs that come with a measles outbreak can also include direct medical charges to care for sick and exposed people, direct and indirect costs for quarantined families, and outbreak–response costs to schools and hospitals, etc.
We should also consider what happens when our state and local health departments have to divert so much time and resources to deal with these types of vaccine-preventable diseases instead of other public health matters in the community.
There were 220 cases of measles in the United States in 2011. To contain just 107 of those cases in 16 outbreaks, "the corresponding total estimated costs for the public response accrued to local and state public health departments ranged from $2.7 million to $5.3 million US dollars."
In contrast, the MMR vaccine only costs about $567.
1. Katz SL, Hinman AR. Summary and conclusions: measles elimination meeting, 16–17 March 2000. J Infect Dis 2004:189(Suppl 1):S43–7.
2. Shulman ST, Shulman DL, Sims RH. The tragic 1824 journey of the Hawaiian king and queen to London: history of measles in Hawaii. Pediatr Infect Dis J. 2009 Aug;28(8):728-33. doi: 10.1097/INF.0b013e31819c9720.
3. Gregory Wallace, MD, Susan Redd, Jennifer Rota, Paul Rota, PhD, William Bellini, PhD, Div of Viral Diseases, National Center for Immunization and Respiratory Diseases; Emmaculate Lebo, MBBS, EIS Officer, CDC. Morbidity and Mortality Weekly Report. September 13, 2013 / 62(36);741-743
4. 2014 Joint Commission Hospital Accreditation Standards. Accessed March 18, 2014.
5. APIC Text Online.www.apic.org. Accessed March 14, 2014.
6. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/meas.pdf. Accessed March 14, 2014.
7. Ortega-Sanchez, Ismael R.The economic burden of sixteen measles outbreaks on United States public health departments in 2011. Vaccine, Available online 14 October 2013