The cost of a preventable outbreak

Vaccine refusal or delay played a major role in the 2013 measles outbreak-New York City’s largest since 1992-that cost the New York City Health Department nearly $400,000, according to a new report.

The report, published in JAMA Pediatrics, highlights the New York City Health Department’s response and the public health toll of the outbreak.¹

Danielle De Souza, a spokesperson for the New York City Health Department, says the department learned that it is important to keep vaccine-preventable diseases on the list of differential diagnoses for patients with fevers or rashes-particularly when they have had recent international travel or when there is an active outbreak.

“The outbreak was fueled by the introduction of measles virus into a small number of families who had previously declined vaccination. They accounted for the majority-71%-of identified cases,” De Souza says.

The report assessed the response of health officials during the outbreak and included a cost analysis. Overall, there were 58 cases of measles in the outbreak and 3351 exposed contacts. Nearly 80% of the age-eligible cases were unvaccinated because of refusal or intentional delay, according to the data.

“Measles vaccine refusals or delays can lead to large outbreaks following measles importations, with costly and resource-intensive response and containment,” the report notes.

Characterized by a generalized rash with fever, measles is highly contagious and is transmitted through airborne and respiratory droplets. Nearly all-90%-of individuals exposed to the virus become sick, with infection beginning 4 days before a rash ever appears, extending the period during which infected individuals remain active and spread the virus. It’s for these reasons that a single case of measles can quickly and easily result in large outbreaks, according to the researchers. Postexposure prophylaxis can provide some help in an outbreak, the report notes, but the window for use is narrow.

Although measles was declared eliminated in the United States in 2000, its virus remains active around the world, and public health officials have long stood by the recommendations for sustaining the 2-dose measles/mumps/rubella (MMR) vaccine nationally.

Some pockets of the population have refused or delayed these vaccines, however, and researchers after the New York City outbreak tied the incident to an unvaccinated 13-year-old who had recently traveled abroad and brought the virus back. The patient had visited a doctor upon return from the trip, but the clinician didn’t report the suspected case until lab results confirmed measles-8 days after the initial patient visit.

The outbreak was characterized largely by the community in which patient cases were centered. All 58 infected individuals were Orthodox Jewish and resided in 2 Brooklyn neighborhoods, and the report concluded that the tight-knit nature of that community likely prevented further spread of the outbreak, although family-based infections were also a big part of the outbreak. Forty-one of the 58 individuals infected with measles were members of 8 extended families, and 52% of cases were believed to have come from a relative. Other transmission sources included building of residence, friend or playmate, healthcare setting, and community gathering.

In addition to the 78% of children aged 1 year and older who were not given the measles vaccine because of parental refusal or delay, the study also found that just 48% of those who were infected during the outbreak visited a healthcare provider who suspected measles and reported the case to the health department after the initial assessment.

As far as the healthcare response to the outbreak, the report found that in 7% of cases, patients visited a healthcare professional, but measles was not suspected. In 5 cases, rashes were present when the patients visited a doctor, but the cases were not reported to the health department. Thirty-six percent of the patients didn’t seek medical help for their rash and were identified only through contact tracing of secondary-case patients, according to the report.

Additionally, patients in many cases were not placed into airborne isolation precautions, resulting in additional exposures at 11 separate healthcare facilities.

“It is essential to notify the local health department immediately to ensure outbreak control measures are taken to prevent further spread and illness,” De Souza says. “Suspect measles cases also need to be put in airborne isolation to prevent transmission in health facilities. In a practice without an isolation room, a patient can be seen and brought into a room after all other patients have left.”

The direct cost of the outbreak to the health department was $394,448, and more than 10,000 personnel hours were spent responding to and controlling the outbreak, according to the report.

“Vaccine refusals and delays appeared to have propagated a large outbreak following importation of measles into the United States,” the report concluded. “Prompt recognition of measles along with rapid implementation of airborne isolation of individuals suspected of measles infection in healthcare facilities and timely reporting to public health agencies may avoid large numbers of exposures. The response and containment of measles outbreaks are resource intensive.”

Outbreak control efforts included MMR vaccination given within 3 days of exposure to 114 patients who were aged older than 6 months, and immunoglobulin within 6 days of exposure to infants who could not or did not receive the MMR prophylaxis, according to the report.

“This outbreak was fueled by the introduction of measles virus into a small number of families who had previously declined vaccination. The outbreak was prolonged, in part, owing to the spread of measles to infants too young to have been vaccinated and to the delay of vaccination among children,” researchers conclude.

Of the patients and contacts observed in the report, 66% had immunity based on 2 doses of the MMR vaccine or through natural immunity; 11% had had 1 dose of a measles-containing vaccine; 10% were susceptible; and 13% had no record or knowledge of their immunity status.

“I would hope this report demonstrates how important measles vaccination is and that there are serious consequences of not being vaccinated,” De Souza says. “Further, as stated above, clinicians should consider measles in the differential diagnosis of a patient with fever and a rash, especially if they have travelled internationally or there is a reported outbreak. Also, it is critical to notify the local health department immediately to ensure measures are put in place to prevent further spread and illness.”

References:

1. Rosen JB, Arciuolo RJ, Khawja AM, Fu J, Giancotti FR, Zucker JR. Public health consequences of a 2013 measles outbreak in New York City.JAMA Pediatr. 2018;172(9):811-817.