COMMENTARY

John Bartlett's Game Changers in Infectious Disease: 2011

John G. Bartlett, MD

Disclosures

October 26, 2011

In This Article

Measles Outbreak

In 2008 a traveler from Switzerland visited a hospital in Tucson, Arizona and subsequently became the source of 14 cases of healthcare-associated measles.[29] Half of these patients were over the age of 18 years, 4 were hospitalized, 7 acquired measles in the healthcare setting, and none had evidence of measles vaccination. Two hospitals were involved, and the total cost of the evaluation was $799,136.

Serologic testing of the potentially exposed healthcare personnel indicated that measles immunity was lacking in 1776 of 7195 (25%) tested individuals. Most of the costs were for contact tracing, a measles vaccine program for healthcare workers in 7 community hospitals, and a total of 15,120 hours lost in healthcare worker furloughs. The evaluation involved 8231 contact investigations, including 6470 (79%) investigations for contact with the index case, largely as a result of delayed diagnosis. The result was a mean cost per case of $105,347 in one hospital and $167,052 in the second hospital.

This report documents the health and economic consequences of measles, one of the most important yet largely eliminated pediatric infectious diseases (measles, pertussis, and mumps). These conditions, once believed to be conquered, are now being encountered by physicians, many of whom have never before seen these diseases. Measles is the most contagious of all infections and can be fatal.[30]

The history of measles eradication began with the single-dose vaccine in 1963, followed by the double-dose measles, mumps, and rubella vaccine in 1989. Elimination of the disease was declared in the United States in 2000.[30] All of the cases in this report were persons who were unvaccinated or had no verification of vaccination. It is unknown how many had actually been vaccinated, but 25% of the healthcare workers sampled had no evidence of measles immunity. This could indicate either lack of vaccine or vaccination with waning immunity.

Why Is This a Game Changer?

The measles cases nicely illustrate the challenge of what we are now encountering in the form of pediatric preventable diseases. The issue of vaccine preventable diseases has also extended to painful lessons with pertussis and mumps. During 2010, 9477 cases of pertussis were reported in California, including 10 infant deaths.[31] This is the most cases of pertussis reported in the last 65 years and has prompted a new California law that requires a booster vaccine for pertussis, tetanus, and diphtheria for all students in grades 7-12. Michigan reported 902 cases of pertussis in 2009, and 964 pertussis cases were reported in Ohio.[28] The same scenario has been seen with mumps, with a surge of cases following late recognition of the index case -- a boy who had visited the United Kingdom in 2009.[32]

The infamous Wakefield report in The Lancet has now been retracted as a result of well-recognized flaws in reporting and conflicts of interest, but the damage persists.[33] Among the 14 victims of measles in Arizona, none had evidence of vaccination, and this is an increasing concern with both mumps and pertussis. The problem is achievement of sufficient vaccination for herd immunity, which should be successful based on experience with smallpox and H influenzae type B. The current problem is sizeable in terms of numbers of unvaccinated individuals[29] and magnified by the potential vulnerability of those who have been vaccinated but have lost immunity due to immunosuppression, aging, etc.

Some have opined that individual rights preclude mandated vaccinations without considering the associated societal risks. Mandatory influenza vaccination for healthcare workers illustrates this point.[34] Some pediatricians are now rejecting care of pediatric patients whose parents refuse routine childhood vaccinations.

This article by Chen was cited because of the importance of recognizing pediatric infectious diseases and to highlight an important ethical debate that pits individual rights vs societal health benefits.

What Does This Mean to the Practitioner?

  • Concern is high for vulnerable individuals who have not been vaccinated, or whose immunity is waning or lost, resulting in a reduction in herd immunity. One of the major challenges is early recognition to prevent the very extraordinary and expensive requirement for epidemiologic investigation, which expands exponentially with delayed diagnosis.

  • The standard case definition of measles is: fever (over 38.3ºC), a characteristic generalized maculopapular rash lasting more than 3 days, cough, coryza, and/or conjunctivitis. A patient with these symptoms needs prompt isolation and diagnostic testing.

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