Imported measles cases hit hospitals; prompt diagnosis, HCW records vital
Imported measles cases hit hospitals; prompt diagnosis, HCW records vital
Undiagnosed cases infecting patients, at least one worker
Infection control professionals should heighten suspicion for measles and know the immune status of health care workers after a literal rash of imported cases nationally has resulted in nosocomial transmission to patients and considerable chaos at hospitals.
Virtually eradicated in the United States due to effective childhood immunization programs, measles may not be initially diagnosed by unsuspecting clinicians. However, several international outbreaks are occurring and travelers arriving in the United States may go undiagnosed even if they present with the classic signs of rash and fever. "We have encountered a number of situations where there has been considerable delay in isolation because the [infection] is not being recognized," says Jane Seward, MD, deputy director of the division of viral diseases at the Centers for Disease Control and Prevention. "[They] are sometimes waiting until lab results came back a couple of days later for a case to be isolated in the hospital."
In the interim, the highly infectious, airborne virus can be transmitted to any susceptible staff and patients. "If it's a rash and fever and people have traveled, measles need to be considered," Seward tells Hospital Infection Control. "Also, [be aware of] people who come in contact with travelers. Awareness — then isolation in health care settings. They should be in a negative-pressure room; but if you don't have one, put them a room with the door closed. Put a mask on the patient if they will tolerate it and wear a mask [when entering the room]."
Measles is a highly contagious disease that is transmitted by respiratory droplets and airborne spread. Infection can result in severe complications, including pneumonia and encephalitis. The incubation period for measles ranges from seven to 18 days. A diagnosis of measles should be considered in any person with a generalized maculopapular rash lasting three or more days, a temperature of 101°F or higher, and cough or conjunctivitis. The CDC warns however, that immunocompromised patients may have atypical rash or no rash at all.
Unless promptly isolated, once the imported case is discovered a massive follow-up must ensue to determine the immune status of patients and workers who may have been exposed. Thus, the immediate message for ICPs is to think measles in suspect patients and ensure their employee health colleagues have worker records of measles immunity on file.
"That is very important because if a measles case occurs, hospitals have to rapidly look at evidence of immunity for all their health care personnel," Seward stresses. "And if it's not documented somewhere easily then they have a very difficult situation on their hands."
The current acceptable standard for evidence of measles immunity is either birth before 1957, receipt of measles vaccine, a physician-confirmed diagnosis of measles, or serological evidence of immunity. "In an outbreak setting — once you have measles cases in a hospital — then everybody has to have evidence of immunity immediately," she says. "Have those records available electronically so that it is quick to pull them up and look. If you don't have it on file, then you just need to vaccinate."
If it's global, think local
Time and again, we are reminded in the infectious disease world that anything global can suddenly appear as a local threat. Although measles no longer is an endemic disease in the United States, it remains endemic in most countries of the world. Large outbreaks currently are occurring in Switzerland and Israel. In the United States from Jan. 1 through March 28, 2008, 24 confirmed cases of measles resulted from importations from endemic countries, the CDC reported in a health advisory.
"We have had a number of cases this year in different parts of the country — Virginia, San Diego, New York City, right now in Seattle and Oregon and Arizona," Seward says. "Because they are fairly severe, measles cases almost always show up in a hospital or health care setting. They go often multiple times to physicians' offices because people don't recognize measles anymore. They might show up at an emergency room and sit around and people don't necessarily isolate them."
The global nature of measles in an era of rapid international travel is underscored by some of the reported outbreaks. In January and February 2008, San Diego experienced an outbreak of 11 measles cases, with an additional case-patient who was exposed in San Diego but became ill in Hawaii. The index case was an unvaccinated child who had recently traveled to Switzerland, where a measles outbreak is ongoing. Transmission in that outbreak occurred in a doctor's office as well as in community settings. Confirmed measles cases in New York City were identical to a strain circulating in Israel, while Virginia was hit with a strain from India. As this issue went to press, a measles outbreak that began with a case from Switzerland is ongoing in Tucson, AZ, and has caused considerable angst at two hospitals and the Pima County Health Department. "It's a mess," says Patti Woodcock, community relations manager at the health department.
The first case, with rash onset on Feb. 12, 2008, occurred in an adult visitor from Switzerland who was hospitalized at Northwest Medical Center in Tucson with measles and pneumonia. This hospital admission prompted verification of the measles immune status of approximately 1,800 health care personnel and vaccination of those without evidence of immunity. Through April 11, 2008, 10 confirmed cases have been reported to the Arizona Department of Health Services. Eight of the patients were infected nosocomially. The 10 case-patients were all unvaccinated and range in age from 10 months to 50 years. One of the cases is apparently a health care worker at Northwest, though the hospital would neither confirm nor deny it and the CDC reported the case without institutional identifiers.
HCW was not immunized
"One of the cases in Arizona was in a health care worker," Seward says. "She had not been immunized before and was born after 1957. She was somebody that slipped through the cracks and hadn't been offered vaccine. There is quite a lot of turnover in hospital staff and it is a lot of work to keep people up to date. She in fact was not hospitalized, but measles can be quite severe in adults. There have been five adult cases in this outbreak in Arizona and three of them have been hospitalized, including one of them in an intensive care unit."
As a result, the hospital and public health department have had to follow up "hundreds, maybe a thousand contacts or more," Seward says. "I know regarding just one of their cases — who was in the intensive care unit — they had 185 contacts in the hospital. These were people in the health care setting, so that didn't include community contacts. Typically, one measles case alone involves following up on hundreds of contacts."
In response to questions from HIC about the measles outbreak, Kim Chimene, director of marketing at Northwest Health released the following statement and permitted reprint of a form used to track and identify potential measles cases (see measles screening tool):
"Northwest Medical Center worked closely with the Pima County Health Department upon confirmation of a patient with measles," the statement reads. "In partnership with the health department, the plan included taking diligent and rapid steps to notify employees, medical staff, patients, visitors and the community of the potential exposure — as this is a community risk, not just a hospital-based risk. Screening of individuals concerned about possible exposure has been conducted by the health department, which continues to monitor the situation. The hospital remains vigilant in identifying potential measles cases, including a patient intake screening tool, and has appropriate procedures for follow-up isolation, if necessary. We will not identify any individuals with confirmed or suspected cases of measles."
According to Seward, the "initial case in Arizona was a Swiss lady who was unvaccinated. People just didn't think of measles when she came in." Indeed, the second hospital involved in Tucson, the University of Arizona Medical Center, found itself in a similar plight after a sick 2-year-old presented at the emergency department. The child was admitted but not diagnosed with measles, so he was not placed immediately in airborne isolation. "We had a child here on April 3 that presented in our ED with no rash," Katie Riley, office of public affairs at the hospital, tells HIC. "We admitted him; and two or three days later, a rash showed and we have isolated him. Now we have as many as 500 people we have to track."
The total includes health care workers, but she did not have a specific breakdown of the numbers. "A condition of employment here, as I assume in most hospitals, is immunity to measles," she says. "We are going back through all records to see if everybody can prove that either through documentation of vaccination or serologically. If [they] can't do that, they have to go in and get another MMR [shot]. [Employee health] has been working hard from the second we found out. They hit the ground running and I know they were able to very quickly identify the very few people who needed a shot."
No secondary cases had been identified as this issue went to press.
Of note, the pediatric case was the first in the Arizona outbreak to have no epidemiological link to the index Swiss case. "This means the measles virus is circulating in our community," Michelle McDonald, MD, chief medical officer for the Pima County health department, said at a press conference.1 "Measles is the most contagious disease we know of, so it is very likely there are other people out there who have been infected."
Indeed, though the sick child was promptly admitted, there was concern that the virus may have lingered in the air and infected people who later entered the emergency department. The hospital urged anyone that was in the ED during a nine-hour period on the day in question to contact the health department and determine their risk of infection.
CDC rethinking heath care advice
As a result of the outbreaks, the CDC is considering changing some of its recommendations regarding health care immunizations, Seward says. In particular, the 1957 birth demarcation can be confusing because the recommendations say "consider" administering immunizing these older workers on hire, but then "strongly consider" giving them shots if there is a measles outbreak.
"The language now of 'consider' administering a dose is not a strong recommendation, so most hospitals consider birth before 1957 as evidence of immunity," she says. "Then when a case occurs they are faced with then having to check immunity in their people born before 1957 [via blood tests]," she says. "In Arizona, that was more than 400 health care workers. So then they had to scramble and do that very quickly. The blood test [detects] antibodies to measles, either from natural disease — which probably most people born before 1957 would have acquired — or it could be immunity by vaccination. Either way, if there are antibodies, then we consider people immune."
CDC advisory committees on immunization and infection control will discuss revising the recommendations in upcoming meetings. Any revisions would be to "ensure that everybody has evidence of immunity on file and to be better prepared if a measles outbreak were to occur," Seward says. "Some of the ways that have been suggested are to build it into annual flu vaccination campaigns or TB testing or other things that are done regularly. You could go through all your staff and check new staff coming in for evidence of measles, mumps, rubella, and varicella [immunity]."
Imported cases will continue
Indeed, imported cases are likely to continue and some level of susceptibility remains in U.S. populations that have never had measles and/or declined vaccine for religious or other reasons. The vaccine is highly effective in providing immunity so the vast majority of cases will occur in the unimmunized. "Israel is currently experiencing an outbreak of over 1,000 cases due to a population that refuses vaccination," Seward says. Other countries like the United Kingdom and Switzerland have a persistent level of endemic transmission ongoing because they are not as effective as the United States in achieving high vaccine coverage, she says.
"People need to remain aware that measles can come in to the country," Seward says. "We are at risk for importation until measles is eradicated globally and that is not close on the horizon despite great advances in measles control. If we drop our vaccine coverage much in this country, we are at risk of measles becoming endemic again."
Reference
- McClain C. "Measles case: 500 may be at risk." Arizona Daily Star. April 11, 2008. Available at: http://www.azstarnet.com/metro/233910.
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