Coordinated effort limited number of infections to 22, but thousands exposed
A coordinated county, state and federal response to a measles outbreak in southern Arizona succeeded in curtailing what potentially could have been more than 22 cases at most.
Officials in Pima County haven’t officially declared the outbreak over, but containment is at hand.
“They were very good at getting in and intervening,” said Dr. Karen Lewis, a medical director with the Arizona Department of Health Services. “The challenge you have is measles is not easily recognized nowadays because physicians haven’t seen it for 30 years, and so not all patients are identified immediately as possibly having measles.”
The initial case, identified in February, was a woman visiting from Switzerland who showed up twice at a hospital emergency room, the first time without the telltale measles rash.
Once she was diagnosed, authorities moved quickly to isolate her so that the air she breathed was not recirculated inside the hospital. Measles is an airborne infectious disease.
The next step was twofold: identifying whether the hospital’s health care personnel were immune to measles, and then tracking all contacts that the patient had with other people during her visit, said Dr. Michelle McDonald, the county health department’s chief medical officer.
The woman’s case and a second case identified in Pima County also in a hospital setting occurred during a busy flu season with emergency rooms full of sick people.
“We were smack-dab in the middle of this year’s flu season,” McDonald said, “and would probably have not had quite so much spread in the hospitals otherwise.”
“You have many more contacts than you might have in a home or a doctor’s office, and many more people who may be compromised,” State epidemiologist Ken Komatsu added.
Even so, Komatsu said “in the strategy of controlling the outbreak, they were able to focus on identifying cases early on and vaccinating around each case – all their contacts – within 72 hours. That way, you can prevent the spread if you can do that effectively.”
Through the cooperation of the community, the hospital and county, state and CDC’s efforts combined to control the outbreak in a timely fashion, he added.
Determining immune status for health care personnel throughout the community including through blood tests was a huge issue as the outbreak went on, McDonald said.
“Most of the health care providers did not have documentation of immunity to measles,” even though many of them probably were immune, she said.
Those checked ranged from workers in hospital housekeeping and food service departments to people delivering newspapers daily and “breathing the air. It involved thousands of people across our hospitals in town,” McDonald said.
The process involved going through work rosters, checking patient lists in hospital wards and interviewing people to determine where they were during the onset periods and with whom they had close contacts.
“That’s the kind of huge amount of work involved in these huge outbreak investigations,” said Jane Seward, deputy director of viral diseases with the Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases in Atlanta. “And in hospitals, making sure that all health care workers have evidence of immunity.”
Officials determined that 1,700 people were exposed in the first case alone.
In all, those exposed will total in the thousands, McDonald said.
Costs and the number of vaccinations doctors’ offices provided haven’t been determined, but community agencies and the county health department vaccinated more than 6,000 nonimmune people potentially exposed.
Seward said a preliminary estimate determined that it cost public health agencies $180,000 to deal with an outbreak of 11 measles cases in San Diego this year.