Why Measles Outbreaks Are Resurfacing in the US

Measles was declared halted in the US over 20 years ago thanks to widespread vaccination. Before the 1960s vaccine, nearly every child got measles, leading to pneumonia, hearing loss, and 400–500 deaths annually. Yet as of today, there have been 1,197 confirmed cases in 34 states, mostly among children. The largest outbreak in west Texas has hospitalized 96 people and caused two unvaccinated school-age deaths, while New Mexico has also reported a measles-related fatality.

Vaccination Rates and Herd Immunity

Measles outbreaks are highly preventable. When 95 percent of a community is vaccinated, herd immunity protects everyone. But national kindergarten vaccination rates fell from 95 percent in 2019 to 92 percent in 2023. In Texas counties, rates are below 95 percent in about half of them—and the west Texas outbreak community reports only 82 percent coverage. Of recent cases, only 3 percent were fully vaccinated; 2 percent had one dose; the rest were unvaccinated or unknown.

How Measles Spreads and Manifests

  • Measles virus spreads through the air and lingers for hours after a cough or sneeze.
  • Up to 90 percent of nonimmune people exposed become infected—far more contagious than flu, COVID-19, or Ebola.
  • Incubation is 7–14 days. Early symptoms mimic colds: fever, cough, runny nose. Koplik spots (tiny white mouth spots) can appear a few days in but are often missed.
  • A distinctive skin rash follows. People are contagious days before spots or rash appear, so exposures multiply before diagnosis.

Possible Complications

Measles is not just a mild viral illness. Complications include:

  • Pneumonia and dehydration
  • Ear infections and diarrhea
  • Encephalitis (brain inflammation)

These are most common in children under 5, adults over 20, pregnant women, and immunocompromised people. Measles deaths occur in up to 3 per 1,000 cases. Recent outbreaks have led to hospitalization in about one in eight cases.

Immune Amnesia

A 2019 Harvard Medical School study found measles may wipe out up to 75 percent of a child’s antibody protection against other infections—flu, herpes, pneumococcus, and more. “If your child gets measles and then pneumonia two years later, you wouldn’t necessarily tie the two together,” said Dr. Michael Mina.

Vaccine Protection and Safety

  • Two doses of the measles vaccine offer 97 percent protection. Breakthrough cases are rare, milder, and less contagious.
  • Vaccine side effects are minimal: arm soreness, low-grade fever, muscle aches—typical of many immunizations.
  • Discredited claims linking measles vaccination to autism have fueled hesitancy and falling vaccination rates.

Looking Ahead and Taking Action

Experts warn that cases and deaths will likely rise as vaccination rates fall—an estimated 9–15 million US children may now be susceptible. The good news: measles can be contained and ultimately eliminated.

To protect yourself and your family:

  • Ensure children and adults receive two doses of measles vaccine according to guidelines.
  • Engage respectfully with vaccine hesitant individuals and share reliable information on measles risks and vaccine safety.