ID Consult: Measles

Kristina A. Bryant, MD

January 11, 2023

I received a call late one night from a colleague in the emergency department of the children's hospital. "This 2-year-old has a fever, cough, red eyes, and an impressive rash. I've personally never seen a case of measles, but I'm worried given that this child has never received the MMR vaccine."

By the end of the call, I was worried too. Measles is a febrile respiratory illness classically accompanied by cough, coryza, conjunctivitis, and a characteristic maculopapular rash that begins on the face and spreads to the trunk and limbs. It is also highly contagious: 90% percent of susceptible, exposed individuals become infected.

Admittedly, measles is rare. Just 118 cases were reported in the United States in 2022, but 83 of those were in Columbus just 3 hours from where my colleague and I live and work. According to City of Columbus officials, the outbreak occurred almost exclusively in unimmunized children, the majority of whom were 5 years and younger. An unexpectedly high number of children were hospitalized. Typically, one in five people with measles will require hospitalization. In this outbreak, 33 children have been hospitalized as of Jan. 10.

Public health experts warn that 2023 could be much worse unless we increase measles immunization rates in the United States and globally. Immunization of around 95% of eligible people with two doses of measles-containing vaccine is associated with herd immunity. Globally, we're falling short. Only 81% of the world's children have received their first measle vaccine dose and only 71% have received the second dose. These are the lowest coverage rates for measles vaccine since 2008.

2022 joint press release from the Centers for Disease Control and Prevention and the World Health Organization noted that "measles anywhere is a threat everywhere, as the virus can quickly spread to multiple communities and across international borders." Some prior measles outbreaks in the United States have started with a case in an international traveler or a U.S. resident who contracted measles during travel abroad.

In the United States, the number of children immunized with multiple routine vaccines has fallen in the last couple of years, in part because of pandemic-related disruptions in health care delivery. Increasing vaccine hesitancy, fueled by debates over the COVID-19 vaccine, may be slowing catch-up immunization in kids who fell behind.

Investigators from Emory University, Atlanta, and Marshfield Clinic Research Institute recently estimated that 9,145,026 U.S. children are susceptible to measles. If pandemic-level immunization rates continue without effective catch-up immunization, that number could rise to more than 15 million.

School vaccination requirements support efforts to ensure that kids are protected against vaccine-preventable diseases, but some data suggest that opposition to requiring MMR vaccine to attend public school is growing. According to a

more-than-4-in-10-republicans-and-a-third-of-parents-now-oppose-schools-requiring-children-to-get-vaccinated-for-measles-and-other-illness-up-since-the-covid-19-pandemic-began/">2022 Kaiser Family Foundation Vaccine Monitor survey

, 28% of U.S. adults – and 35% of parents of children under 18 – now say that parents should be able to decide to not vaccinate their children for measles, mumps, and rubella. That's up from 16% of adults and 23% of parents in a 2019 Pew Research Center poll.

Public confidence in the benefits of MMR has also dropped modestly. About 85% of adults surveyed said that the benefits of MMR vaccine outweigh the risk, down from 88% in 2019. Among adults not vaccinated against COVID-19, only 70% said that benefits of these vaccines outweigh the risks.

While the WHO ramps up efforts to improve measles vaccination globally, pediatric clinicians can take steps now to mitigate the risk of measles outbreaks in their own communities. Query health records to understand how many eligible children in your practice have not yet received MMR vaccine. Notify families that vaccination is strongly recommended and make scheduling an appointment to receive vaccine easy. Some practices may have the bandwidth to offer evening and weekend hours for vaccine catch-up visits.

Curious about immunization rates in your state? The American Academy of Pediatrics has an interactive map that reports immunization coverage levels by state and provides comparisons to national rates and goals.

Prompt recognition and isolation of individuals with measles, along with prophylaxis of susceptible contacts, can limit community transmission. Measles can resemble other illnesses associated with fever and rash. Washington state has developed a screening tool to assist with recognition of measles. The CDC also has a measles outbreak toolkit that includes resources that outline clinical features and diagnoses, as well as strategies for talking to parents about vaccines.

Dr. Bryant is a pediatrician specializing in infectious diseases at the University of Louisville (Ky.) and Norton Children's Hospital, also in Louisville. She is a member of the AAP's Committee on Infectious Diseases and one of the lead authors of the AAP's Recommendations for Prevention and Control of Influenza in Children, 2022-2023. The opinions expressed in this article are her own. Dr. Bryant disclosed that she has served as an investigator on clinical trials funded by Pfizer, Enanta, and Gilead. Email her at

This article originally appeared on, part of the Medscape Professional Network.


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