With the call for a vaccine to prevent the spread of the newly identified coronavirus (2019-nCoV), we should not lose sight of a virus we know, for which there has been a vaccine in use for more than 50 years: measles. Measles, one of the most contagious infectious diseases, is the canary in the immunization coal mine. Previously a near rite of passage, annually infecting 3 to 4 million US children and causing 400 to 500 deaths, measles steadily declined after the 1968 introduction of a safe, highly effective vaccine to the point of declared national elimination (in 2000).
Yet multiple outbreaks highlight the urgency for continued vigilance. For example, in the United States, a 1989-1991 resurgence (causing 55 000 cases and 130 deaths), primarily involving unvaccinated urban minority children, prompted both the 1993 creation of the federal Vaccines for Children program, which entitled low-income children to no-cost vaccines, and the adoption of the current 2-dose immunization strategy. More recent outbreaks have involved visitors to Disneyland (in 2014), an Amish community in Ohio (in 2014), and Somali-American communities in Minnesota (in 2017), among others. The most recent 2019 resurgence, representing a 25-year US high, totals more than 1200 cases in 31 states, most notably in orthodox Jewish communities in New York. The canary continues to warn.
Using Data, not Outbreaks, to Identify Vulnerable Communities
Even though the nation has seemingly high (94.7%) aggregate coverage rates of kindergarteners receiving the recommended 2 doses of measles, mumps, rubella (MMR) vaccine, only 20 states actually exceed the 95% community protection threshold sufficient to protect those who cannot be vaccinated for medical reasons. In the era of big data, vaccination programs must come of age. Instead of simply chasing disease clusters, more proactive strategies should identify pockets of underimmunized communities highly vulnerable to a single infected traveler returning from overseas. Such strategies can include modernizing immunization registries and incorporating electronic health records, integrating vaccination information from nonmedical sites (such as pharmacies, community centers, and schools), and fully using barcode technology to track every vaccine dose to map community-level protection in real time.
Addressing Generational Challenges
Ironically, progress in immunization has left parents—and clinicians—far less familiar with measles and other serious vaccine-preventable conditions. Many younger health professionals may have never seen a case. For parents, near eradication has brought the luxury of equivocation, especially in a social media environment where instantly disseminated—though scientifically discredited—misinformation can skew perceptions of social norms. Vaccines should not become the victims of their own success.
Following calls from health professionals, including the American Medical Association, major social media platforms have begun limiting untrue information, directing people to evidence-based websites from the US Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and other reputable sources. Only a start, such efforts must broaden to stop the contagion of social media misinformation.
Reinforcing Effective Communication About Safety and Social Norms
A 2016 Pew Research Center survey of a nationally representative sample of 1549 adults found that most (88%) believe inoculation benefits outweigh risks; 82% support MMR vaccination of all healthy schoolchildren. However, parents of young children who are considering vaccination for the first time may have more concern.
About 80% of parents say their primary care physicians or nurses were trusted sources of information when making vaccination decisions. Hence, pediatricians, among others, are best positioned to communicate immunization as the standard of care. Some research notes that clinicians communicating a presumptive approach that emphasizes vaccination as part of that standard can reinforce its importance. Further research should explore if improved reimbursement for busy clinicians providing parental counseling might increase acceptance and uptake, similar to other preventive areas such as tobacco cessation.
Safety, a foundational element of the US National Vaccine Plan, is central to vaccination success. Yet the public, including clinicians, is likely unaware of rigorous safety evaluations during vaccine development and after public release. Monitoring includes multiple national mechanisms, including the Vaccine Safety Datalink and the Vaccine Adverse Events Reporting System (established nearly 30 years ago). Globally, the WHO is updating its Vaccine Safety Blueprint to ensure that all countries build and strengthen their vaccine safety capabilities.
Evaluating State Nonmedical Exemptions
The CDC’s Advisory Committee on Immunization Practices makes vaccine recommendations; however, only state legislatures have the authority to require vaccinations in certain settings (such as schools), representing “restraints to which every person is necessarily subject for the common good.” Until recently, only 2 states, Mississippi and West Virginia, prohibited all nonmedical (religious, philosophical, or both) exemptions; they have nationally leading MMR immunization rates of about 99%. Following the 2014 Disneyland outbreak, California eliminated nonmedical exemptions for all childhood vaccinations, reducing unimmunized kindergartners from 9.84% to 4.87%. The 2019 outbreaks pushed Maine and New York to eliminate nonmedical exemptions as well; Washington State eliminated personal and philosophical exemptions for MMR only. Although the status of religious exemptions remains debated, a study of 60 outbreaks in religious communities found that the reasons for declining immunization were rarely theologically based. In fact, faith leaders, including New York rabbis, have regularly served as critical community advocates for vaccination as part of promoting health.
To inform future decision-making, states can standardize widely variable procedures for granting and documenting exemptions. Any narrowing of nonmedical exemptions must be carefully evaluated and monitored to assess the effect on public response and vaccine coverage, among other dimensions.
Respecting Global Context
Although increased access to vaccines has substantially reduced morbidity and mortality, newly released global data note measles cases rose 300% in the first 3 months of 2019 (compared with the same period in 2018). Most of the more than 140 000 deaths in 2018 were among children younger than 5 years.
Each national outbreak requires a root cause analysis. For example, the Democratic Republic of the Congo has, in addition to a highly publicized Ebola epidemic, an equally deadly—and the world’s largest—measles epidemic (>310 000 suspected measles cases reported and >6000 deaths to date); the twin epidemics reflect weak health systems struggling to operate in the midst of conflict.
Other recent outbreaks throughout the world include the Philippines (resulting from a weak immunization program coupled with distrust from a flawed introduction of a new dengue vaccine); Samoa (resulting from very low measles vaccination rates related to public distrust of the MMR vaccine); and developed regions of Europe (nearly 57 000 suspected cases in Ukraine) and Brazil (>50 000 cases).
Open Access: This is an open access article distributed under the terms of the CC-BY License.
Corresponding Author: Howard K. Koh, MD, MPH, Harvard T. H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115 (firstname.lastname@example.org).
Conflict of Interest Disclosures: Dr Koh reported receiving grants from the Robert Wood Johnson Foundation outside the submitted work. No other disclosures were reported.
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Koh HK, Gellin BG. Measles as Metaphor: What Resurgence Means for the Future of Immunization. JAMA Health Forum. 2020;1(1):e200085. doi:10.1001/jamahealthforum.2020.0085