By Philip R. Fischer, MD, DTM&H

Professor of Pediatrics, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN

Dr. Fischer reports no financial relationships relevant to this field of study.

SYNOPSIS: It is expensive to respond to and control measles outbreaks in the United States. Primary outbreak prevention should focus on vaccination of travelers and encouragement of routine vaccine acceptance by those who currently are hesitant to have their children vaccinated.

SOURCE: Rosen JB, Arciuolo RJ, Khawja AM, et al. Public health consequences of a 2013 measles outbreak in New York City. JAMA Pediatr 2018; doi: 10.1001/jamapediatrics.2018.1024. [Epub ahead of print].

Measles is no longer endemic in the United States, but outbreaks can occur after the arrival of infective travelers who have contact with unimmunized residents. In March 2013, an unvaccinated adolescent traveled home from the United Kingdom to New York. (In New York, 97% of children aged 19-35 months have received at least one measles vaccine.) A total of 58 people then became infected with measles in two Brooklyn neighborhoods. Contact tracing revealed six generations of spread between eventual cases during the three months after the arrival of the infected index case.

Eight days after seeking medical care in New York from an astute clinician who suspected measles, the patient received confirmation of the diagnosis from measles IgM results, and the state health department was notified. Of the 58 measles patients eventually identified, none had documentation of previous vaccination. Measles patients were 0-32 years of age (median 3 years); 12 (21%) were younger than 12 months of age (the age of the first routine measles vaccination in the United States). All patients were involved with an Orthodox Jewish community; 71% were from eight extended families.

The health department identified 3,351 exposed contacts of the patients with measles; 66% already had evidence of measles immunity, and an additional 11% had received a single measles vaccine previously. Among at-risk contacts, 114 received measles vaccine within three days of the exposure, and another 77 (those younger than 12 months of age who had not received vaccine within three days of exposure) received immunoglobulin within six days of the exposure. Information about the outbreak was provided to physicians, schools, and daycare providers.

The economic impact of public health services related to the measles outbreak was evaluated. The costs of vaccination, laboratory testing, and personnel time totaled $394,448.

COMMENTARY

In resource-limited countries, vaccine-preventable illnesses such as measles are more common in rural populations where individuals are unable to travel and access vaccinations. The opposite seems to be true in the United States, where measles outbreaks usually begin through contact with a returning/arriving traveler and then spread through families who have chosen intentionally not to avail themselves of available vaccinations.

It is important that all international travelers be up to date with measles vaccination. Unfortunately, not all physicians are successfully taking advantage of opportunities to vaccinate travelers.1 Appropriate immunization of travelers could prevent outbreaks of measles. Then, rapid diagnosis and isolation of infected individuals can help prevent spread to others; the index patient in New York went eight days between a clinical diagnosis and attempts to prevent transmission.

The New York outbreak happened to affect unvaccinated people in an Orthodox Jewish community. In California private schools, high rates (> 20%) of non-medical exemption from vaccination of kindergartners because of “personal beliefs” were seen more frequently in secular and non-Catholic Christian schools than in Jewish, Catholic, and Muslim schools.2 In fact, only 49% of private kindergartens surveyed in California had 95% coverage of measles vaccination.2 Under-immunization was more common in the more expensive schools than in schools with lower tuition fees.2 Thus, affluence actually is associated with less vaccination.

Popular awareness of the problems of non-vaccination can affect behaviors. After a widely publicized 2014-2015 outbreak of measles that spread from a California amusement park to involve 111 patients in eight states and three countries, 38% of physicians reported receiving fewer requests for delayed immunizations than prior to the outbreak.3

 

Pediatricians routinely deal with vaccine-hesitant parents.4 The American Academy of Pediatrics offers guidance to help overcome vaccine hesitancy.5

Even while physicians gain skills working with vaccination-hesitant families, the public health costs of outbreaks, as shown by Rosen and colleagues, are significant. Society uses tangible resources to deal with the consequences of non-vaccination. The societal cost prompts some people to wonder if top-down governmental regulatory intervention also might be helpful.

In fact, regulatory changes in California led to more children receiving vaccinations prior to kindergarten. The state of California chose to make vaccine exemption more difficult for families by requiring a healthcare professional signature even for non-medical exemptions to routine pre-school vaccinations. The rate of children starting kindergarten without measles vaccine because of non-medical exemptions dropped from 3.1% in 2013, prior to the new regulations, to 2.3% in 2015, after the new regulation took effect.6

It behooves physicians to work with patients and families to foster appropriate, timely immunization. In addition, publicizing personal and societal consequences resulting from non-vaccination can help transform some vaccine-hesitant families into vaccine advocates. On a larger societal level, legal regulations can improve vaccination and decrease public health expenditures.

REFERENCES

  1. Hyle EP, Rao SR, Jentes ES, et al. Missed opportunities for measles, mumps, rubella vaccination among departing U.S. adult travelers receiving pretravel health consultations. Ann Intern Med 2017;167:77-84.
  2. McNutt LA, Desemone C, DeNicola E, et al. Affluence as a predictor of vaccine refusal and underimmunization in California private kindergartens. Vaccine 2016;34:1733-1738.
  3. Mohanty S, Buttenheim AM, Feemster KA, et al. Pediatricians’ vaccine attitudes and practices before and after a major measles outbreak. J Child Health Care 2018;1:1367493518786011.
  4. Jacobson RM, St Sauver JL, Finney Rutten LJ. Vaccine hesitancy. Mayo Clin Proc 2015;90:1562-1568.
  5. American Academy of Pediatrics. Immunizations: Vaccine Hesitant Parents. Available at: https://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/immunizations/Pages/vaccine-hesitant-parents.aspx. Accessed Aug. 5, 2018.
  6. Buttenheim AM, Jones M, Mckown C, et al. Conditional admission, religious exemption type, and nonmedical vaccine exemptions in California before and after a state policy change. Vaccine 2018;36:3789-3793.