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Measles outbreaks laborious, costly
Tucson outbreak cost 2 hospitals $800,000
When a single imported case of measles led to a small outbreak in Tucson, AZ, in 2008, two hospitals were forced to spend a total of some $800,000 to contain it, much of that related to ensuring the immunity of employees.1 That incident presents a cautionary tale as the United States struggles with its largest number of measles cases since 1996.
In the first 19 weeks of 2011, 118 measles cases were reported. Most (89%) were related to importation of measles from other countries. Nine outbreaks accounted for almost half (49%) of the cases. And the consequences were serious. Forty percent of the patients with measles required hospitalization.2
"Measles is quite severe," says Jane Seward, MD, MPH, deputy director of the Division of Viral Diseases at the Centers for Disease Control and Prevention in Atlanta and an author of an analysis of the Tucson outbreak. Hospitals need to consider a diagnosis of measles if a patient presents with a cough, fever and rash, she says. "Unvaccinated travelers coming into the United States continue to pose a risk," she says.
The Tucson case revealed just how costly and difficult measles can be for hospitals. A primary concern: Ensuring that all health care workers have immunity. Measles can easily spread to people who are non-immune and to infants too young to have had their measles-mumps-rubella (MMR) immunization.
"Measles is very highly infectious," says Seward. "It's one of the most infectious diseases that we have."
Hospitals typically require new employees to receive two doses of the MMR vaccine or show proof of immunity. People born before 1957 may be presumed to be immune, according to guidelines from the Centers for Disease Control and Prevention although in the event of an outbreak, CDC recommends that health care workers born before 1957 receive two doses of MMR.
In an outbreak situation, hospitals need to be able to verify immunity of employees quickly, says Seward. "I think hospitals in general do recommend MMR vaccine for health care workers. But I think recommending and implementing and evaluating are different things," she says. "A lot of hospitals don't necessarily do the extra work to follow up and see how well those policies are being implemented and if anyone is falling through the cracks."
It can also be a nightmare for public health officials trying to contain an outbreak. "In public health circumstances, we don't accept a report by a health care provider that they're immune," says Stephen Ostroff, MD, director of the bureau of epidemiology in the Pennsylvania Department of Health in Harrisburg.
"Either you have to be able to produce records that show the date you received the vaccine or you have to have a laboratory test that demonstrates with absolute certainty that you're immune. If you can't produce either one of them, then from our perspective you're not immune," he says.
Measles not suspected
The Tucson case began with a 37-year-old traveler from Switzerland who was unvaccinated. She went to a hospital emergency room in Tucson on Feb. 12, 2008 and again the next day, when she was admitted with a fever and rash. Yet measles wasn't initially suspected and she wasn't isolated until two days later.
Meanwhile, a 50-year-old woman who was exposed to the Swiss traveler in the emergency department waiting room developed a fever and respiratory illness. At first, she was diagnosed with asthma exacerbation, then pneumonia and allergic drug reaction. Finally, on March 2, she was diagnosed with measles.
Measles spread from that second patient to several other people. A health care worker, who had just received her MMR vaccine the day she cared for Patient 2, developed fever on March 5 and fever, cough and rash by March 9. An unvaccinated 11-month-old boy who was in an emergency department room across the hall from Patient 2 developed measles, as did two unvaccinated children, ages 3 and 5, who walked past the patient's room while visiting their mother in the hospital.
In all, there were seven cases that were confirmed as health care-associated linked to the index case. Another five developed community-acquired cases and one person who developed measles was exposed to a patient in his home. Of 11 patients who sought medical care at a hospital or physician's office for fever, cough and rash, only one was masked and isolated.
That delay in suspecting measles is a consequence of the success in controlling measles in this country, says Ostroff. But measles is raging elsewhere in the world. France and India were responsible for the greatest number of imported cases in the United States this year.
"Anytime you even remotely suspect this diagnosis, it should be immediately reported to the health department," says Ostroff. "That allows us to get the appropriate testing done and to start identifying the contacts as soon as possible to avoid an additional round of cases."
Furloughs cost $444,000
The outbreak investigation involved 4,793 hospital or clinic patients and 2,868 health care workers. Only 75% of the health care workers at the two hospitals that received patients with measles had evidence of immunity. None of the Tucson hospitals had electronic records that enabled them to quickly determine if their employees were vaccinated or otherwise immune.
Of 1,583 health care workers who had serologic testing, 11% were found to be seronegative. Meanwhile, health care workers without evidence of immunity were vaccinated and furloughed for five to 21 days after their last exposure.
The furloughs alone cost the two hospitals about $444,000, according to the analysis of the outbreak.
"Hospitals can be prepared by just having the evidence [of vaccination or immunity] on file," says Seward. For health care workers born before 1957, "they can choose to vaccinate them routinely or they can have it on file that they need to be vaccinated in the event of an outbreak," she says.
Because measles is so transmissible, it's important to have levels of immunity and vaccination of about 90 percent to 95 percent, says Seward.
"Suboptimal immunization is going to have ramifications in terms of the incidence of disease," says Ostroff. "I would hate for health care providers to become more familiar with measles because there's more disease [in the United States]."
1. Chen SY, Anderson S, Kutty PK, et al. Health care–associated measles outbreak in the United States after an importation: Challenges and economic impact. J Infect Dis 2011; 203: 1517-1525.
2. Centers for Disease Control and Prevention. Measles United States, January–May 20, 2011. MMWR 2011; 60:666-668.