Leana S. Wen: Why it matters if the U.S. loses its measles elimination status

The United States this week reached an unenviable milestone: Health officials have recorded the highest number of new measles infections in more than three decades. So far this year, 1,288 measles cases have been confirmed. In Texas, the epicenter of the largest outbreak, 753 people have been infected.

If cases keep climbing, the U.S. risks forfeiting its measles elimination status. This is consequential for many reasons.

Most important, it would mark the return of measles as an enduring health threat. Since 2000, when measles was declared eliminated, new U.S. cases have been sporadic and mostly linked to international travel. Thanks to high levels of population immunity – experts estimate that 95% of people must have immunity to halt transmission – these outbreaks have typically remained small and been quickly contained.

Unfortunately, vaccination rates have fallen. The Centers for Disease Control and Prevention reports that in 14 states, less than 90% of kindergarten-age children have received the recommended two doses of the measles, mumps and rubella (MMR) vaccine. Many communities have significantly lower rates. In Gaines County, Texas, an area especially impacted by the current outbreak, nearly 18% of kindergarten parents filed an exemption to opt out of required vaccines.

The fewer people with immunity, the more opportunities the virus has to spread and cause disease and suffering. Those who believe that measles is “just a cold” are tragically mistaken.

In Texas, nearly 100 measles patients have been hospitalized this year, and two school-age children have died. As many as 1 in 20 children with measles end up with pneumonia, and about 1 in 1,000 develop brain swelling that could lead to permanent disability. And measles doesn’t just cause acute illness; it can also reset the immune system’s memory, a phenomenon known as immune amnesia, leaving people susceptible to diseases they were once protected against.

If measles becomes endemic again, many Americans will live in fear of contracting the disease. Those especially vulnerable to the virus’ harms are newborns not yet old enough to receive their first shot and severely immunocompromised people who cannot receive a live vaccine. Measles is so infectious that 9 out of 10 unvaccinated people exposed to an infected person will contract the disease.

Even those who are vaccinated would have reason to worry. Though two doses of the MMR vaccine offer 97% protection, breakthrough infections could happen. The elderly and people with underlying medical conditions – the same groups that bore the brunt of isolation during the COVID-19 pandemic – might have to resume precautions to guard against a disease that should be a relic of the past.

This outcome is not as far-fetched as one might think. Venezuela became the first country in the Americas to lose its measles elimination status in 2018 due to collapsing health care infrastructure and plummeting vaccination rates. During the two peak years of endemic transmission there, the country recorded 7,054 confirmed cases and at least 80 deaths. A recent JAMA article found that if MMR vaccination rates in the U.S. declined by another 10%, there could be as many as 11.1 million measles cases over the next 25 years.

Such a resurgence could substantially disrupt tourism and travel. Other countries might warn their citizens not to go to the United States. They might require proof of vaccination before travel or even mandate quarantine and testing after returning.

Health officials would have to divert resources away from other critical needs. More people would fall ill, further straining the health care system. State and local health departments would have to prioritize infectious-disease control over other pressing priorities such as the opioid epidemic and chronic disease prevention. And because the early stages of measles mimic those of other common viral illnesses, widespread concern would lead clinicians to administer many additional tests. Meanwhile, exposed children might be kept home from school and employees from work due to quarantine and isolation protocols, adding to the social and economic toll.

With so much on the line, one would expect the federal government to marshal every resource available to control the escalating crisis before measles cases surged any further. Instead, by spreading misinformation, appointing vaccine skeptics to oversee immunization policy and decimating the agencies in charge of outbreak response, this administration is effectively conducting a real-life experiment. We are about to learn firsthand how many Americans will suffer the needless fallout of a virus we have every means of containing.

Leana S. Wen is an emergency physician, clinical associate professor at George Washington University and author of “Lifelines: A Doctor’s Journey in the Fight for Public Health.” Previously, she served as Baltimore’s health commissioner.