Measles raises a host of challenges for infection preventionists, whether they are responding to a single case or a community outbreak. These include difficulty identifying cases, figuring out if susceptible patients were exposed, checking immunity of healthcare workers, and determining if post-exposure prophylaxis (PEP) or measles, mumps, and rubella (MMR) vaccine should be given.
Once declared eradicated in the U.S., measles is still causing outbreaks in many parts of the world and may show up at any given U.S. hospital in a traveler or a child whose parents did not have him or her immunized.
The latter was the case last year in Minnesota, where measles erupted in an unvaccinated and undervaccinated population of Somali children. Antivaccine groups were peddling the debunked connection between MMR receipt and autism, leading to a decline in MMR immunization among the younger children, says Patricia Stinchfield, MS, RN, CPNP, infectious disease nurse practitioner and senior director of infection control at Children’s Minnesota in Minneapolis.
“We really realized the impact of the antivaccine groups when we looked at our vaccine records and saw the oldest kids were vaccinated, the middle kids had one MMR, and the youngest kids had no MMR — but every other [childhood vaccine],” she told Hospital Infection Control & Prevention at the recent Association for Professionals in Infection Control and Epidemiology (APIC) conference in Minneapolis. “There are some antivaccine groups in Minnesota. They met with the Somali imams and basically told them to tell their mosque members that MMR causes autism. That myth and the fear took hold.”
The outbreak resulted in 75 cases, one of which was a healthcare worker with a history of measles vaccination, said Julie LeBlanc, MPH, CIC, healthcare epidemiologist at Children’s Minnesota, at the APIC conference.
The transmission occurred at the beginning of an outbreak when an emergency department nurse with documented receipt of two doses of MMR was exposed to two undiagnosed measles cases.
Another reported hospital-acquired case of measles was the mother of an infant who came in for treatment unrelated to measles. Again, the exposure occurred in the emergency department before clinicians were aware that a measles outbreak had begun in the community.
Both hospital-acquired cases resulted in mild illness, but added to the chaos as the hospital responded to the outbreak.
The hospital policy is that healthcare workers have evidence of measles immunity on hire. However, as measles vaccination is not 100% effective, the policy calls for healthcare workers to wear respirators when treating known or suspect measles cases.
“You wear an N95 — if you are medically cleared and have done the fit-testing — or wear a PAPR [powered air purifying respirator],” LeBlanc said. “Once we knew we had measles, staff really understood their role in identifying any potential suspect case and getting airborne precautions implemented. We had good compliance.”
Severe Infections
Children’s Minnesota hospital was besieged by the outbreak, ultimately caring for 52 (70%) of the total of 75 total cases in the community.
“Forty-one of those were tested in our facility, and there were an additional 11 tested elsewhere that subsequently came to us for care,” LeBlanc said. “Twenty-one of the cases in the outbreak were admitted, and all those admissions were at Children’s Minnesota.”
Measles may be dismissed by some as minor childhood illness, but these resurgent outbreaks have been marked by some severe infections. One measles patient had a 17-day length of stay in the Minneapolis outbreak. The average length of stay was four days, with a minimum of two days.
The severe measles cases were one of the primary reasons there was a frantic effort to identify exposures and administer PEP or vaccine after the outbreak began, she said, showing a picture of a child from an earlier measles outbreak (used with parental permission).
“This is a patient from our 2011 outbreak that was in our ICU, on a ventilator for 15 days,” LeBlanc said. “This little boy was fortunate and survived, but this is why we work so hard. We want to prevent this from happening to any other child.”
Sprint or Marathon?
LeBlanc traced the beginning of the outbreak as it unfolded at her hospital, beginning with a two-year-old child who presented at the ED. The child had a four-day history of fever, a rash that started the day prior, and cough and congestion. There was no travel history reported, and vaccination record showed the receipt of only one MMR. The patient had been diagnosed with otitis media five days prior and started on amoxicillin.
“The hospitalist admitting this patient thought that the rash was associated with administration of amoxicillin,” she said. “However, measles entered their mind and they ordered a test. Sure enough, it was measles.”
Now the clock was ticking, she emphasized. The patient presented on April 9, and the test was ordered and the positive measles confirmed on April 11.
“The first thing is to figure out the patient’s contagious period of time in which they can transmit measles,” LeBlanc told fellow IPs in the APIC audience. “It starts with rash onset, and this patient’s rash onset was the 8th. So the contagious period was four days before [rash], and four days after.”
The next question is when did the patient go into airborne precautions, which for this case was on April 10 when the test was ordered.
“The patient was not in airborne precautions on the 9th, so we needed to assess exposures for that day,” LeBlanc said.
Looking back on the patient history, LeBlanc and colleagues noticed a problem. The measles patient had actually been in the hospital ED earlier, on April 4 and 6.
“At those visits they were appropriately under contact and droplet precautions based on upper respiratory symptoms, but nobody was thinking measles at that time,” she said.
Depending on when susceptible people were exposed to a case of confirmed measles — and the risk factors of those exposed — there are options to use the vaccine or immune globulin PEP.
LeBlanc and colleagues quickly began looking at those exposed to the index case, getting ready to “sprint” to deliver PEP, when they received some more unwelcome news.
“We found out that the patient in the room next door — who had been there for four days with no airborne precautions — was being tested for measles,” she said.
Complicating matters, the mother of this new patient said her child had a playmate at day care with suspected measles.
“You might be thinking, wow, how did you guys miss the measles on both of these kids?” LeBlanc said. “Neither of them had international travel. They both had symptoms that were very similar to other illnesses. And they both had amoxicillin, which could explain their rash. People with measles are not walking in with a sign over their head.”
In any case, the stakes rose considerably with two confirmed cases in the hospital and the involvement of a day care center in the community.
“We knew we had an outbreak brewing,” she said. “We needed to get ready for a marathon instead of a sprint.”
Outbreak Response
At this point, the hospital began rolling out a response plan for an outbreak in the community, where the public health department was now sounding the alarm.
“These are really the same principles, whether you are responding to one case or an outbreak,” LeBlanc said. “As soon as measles enters the mind as a differential diagnosis, infection prevention needs to know about it.”
The hospital developed triage and testing criteria, emphasizing the use of PCR tests with quick turnaround times. “We don’t want people ordering serology because it is not the right test for active disease,” she said.
“For about six weeks, we were testing for new cases almost every day,” LeBlanc said. “In total, there were 234 tested and ruled out. Overall, there were about 15% that actually had measles. The point being, again, that a lot of kids have fever and rash, and measles can look like a lot of other childhood illnesses.”
As testing was done, infection prevention notified the health department, initiating exposure follow-up for the positive cases. Measles is highly transmissible by the airborne route, meaning many patients in the vicinity of known cases may have been exposed.
“You need to know where the patient was — what departments and rooms were they in?” she said. “Then the time they were there, and when did they leave. Who else was in the same area at the same time?”
The hospital electronic medical records were used to track down answers to these questions, enabling LeBlanc and colleagues to identify discharged patients exposed to known measles cases.
“Now you have your list of who’s exposed, and you need to prioritize them,” she said. “The main element for prioritization is immune status. You want to prioritize people who you know are not immune to measles.”
Calling Patients
Using state vaccination records to prioritize immune status, the hospital developed a script to make phone calls to those with no history of vaccination. Those who received at least one dose were contacted by mail.
“Ideally, you would make a phone call to everyone,” LeBlanc said. “In our outbreak, with such large numbers, that just wasn’t feasible.”
LeBlanc and colleagues worked with the IT department to establish a call bank with a designated line for call-backs. The patients contacted were told about their possible measles exposure, their immune status was verified, and questions were asked about the immune status of their contacts.
“Let them know what to do next, where they need to go, and be ready to address challenges like lack of transportation by providing people taxi vouchers to get to your facility,” she said. “Access to interpreters is essential, both to translate the letters and to interpret phone calls.”
Patients who refused follow-up or could not be reached were referred to the health department.
“This is really about figuring out who can help you,” she said. “We had some nurses from our quality and safety department that were able to help with calls. The relationships that you build in your day-to-day job as an IP are really going to help you in a time-sensitive situation like this.”
As people returned to the hospital for evaluation and possible PEP, LeBlanc and colleagues shunted them away from the ED.
“We set it up in a primary care clinic, but there were still problems with that,” she said.
“You have the people coming in for PEP because they might have measles. You have people coming in to get vaccinated because there is an outbreak and everybody wants the MMR vaccine,” she explained. “And then all of the regular patients that you see every day coming in for non-measles-related reasons.”
In total, the hospital had 745 total exposed patients. There were 489 letters sent out and hundreds of phone calls made.
“There were 173 people who were PEP eligible,” she said. “We were able to successfully reach 138 and give them PEP.”
Ramped-up triage measures included masking symptomatic patients and setting up temporary airborne precaution rooms using portable HEPA filters.
“The majority of our exposures occurred in the time frame before we knew we had measles in the community,” she said. “There were a couple of little spikes, which were learning opportunities. We did real-time process improvements, like the masking on entry. As the outbreak went on and we refined our interventions, we were able to successfully identify and care for confirmed cases of measles without any exposure to other patients.”
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