US suffers largest measles outbreak since 2000 – 5 essential reads about the risks, what to do and what comes next

Measles outbreak in South Carolina It reached 876 cases on February 3, 2026. This number exceeds the outbreak in Texas in 2025 and reaches the unfortunate milestone of being the largest outbreak in the United States since 2000, when the disease was declared eliminated here.

The outbreak reveals the range of risks the disease can pose. The South Carolina state epidemiologist revealed on February 4 that Cases of brain swellingA rare complication of the disease appeared in some infected children, according to Wired magazine.

Some evidence suggests that this particular outbreak Maybe it’s starting to diminish. But many public health scientists worry that a resurgence of measles across the United States and around the world, driven by declining vaccination rates, may signal a pandemic. A coming wave of other vaccine-preventable diseases

The Conversation US has put together a collection of five stories from our archives to help readers gauge the practical considerations around vaccination and the bigger picture of what a measles resurgence might mean for public health.

1. Primer for measles vaccine

Measles is It is one of the most contagious diseases for humans On this planet – far more contagious than familiar infectious diseases such as influenza, Covid-19 and chicken pox. But the vaccine, which is given in two doses, is 97% effective in preventing measles infection, he wrote. Daniel Pastolaa neurologist and medical epidemiologist at the University of Colorado Anschutz Medical Campus.

Most people born after 1957 received the vaccine as children. A striking — though not surprising — feature of the outbreak in South Carolina is that at least 800 of the reported cases occurred in People who have not been vaccinated.

For those who are concerned about the risks and wondering how to protect themselves, Pastola has provided some Basic practical guidance.

“The immunity provided by the vaccine is virtually the same immunity you get from contracting measles itself — but it is vastly safer than encountering the wild virus without protection,” Pastola explained. “The goal of vaccines is to create immunity without the risk of severe infection. It’s basically a rehearsal for the real thing.”

Read more:
Measles cases are on the rise – here’s how to make sure you’re protected

2. Long-term consequences

Most people who become infected with measles experience 10 to 14 days of high fever, cold-like symptoms, eye inflammation, and a rash that begins on the face and spreads throughout the body. Since the infection usually resolves on its own, it is easy to ignore the fact that it can have serious consequences.

“What generally puts people with measles in the hospital is the effects of the disease on the lungs,” he wrote. Peter Cassona biologist who studies viruses at the Georgia Institute of Technology, in an article explaining Risk of infection in the short and long term.

Perhaps the scariest is a condition called… Subacute sclerosing panencephalitis, or SSPEThe virus lies dormant in the brain of a person who has recovered from a measles infection and awakens again 7 to 10 years later to cause “a progressive dementia that is almost always fatal,” Casson wrote.

This result is rare, but it does happen. Los Angeles County Department of Public Health A case was reported in September 2025.

Read more:
Measles can damage the immune system and brain, causing long-term damage, explains a virologist

3. What’s at stake?

There’s a common adage in public health that vaccines are often a victim of their own success. This is especially true of the measles vaccine – because it is so effective, many doctors and nurses practicing today have never seen a case.

Pediatrician for infectious diseases Rebecca Sheen At Michigan State University I explored recent modeling studies that Predicting the trajectory of measles infection rates. One study I described in 2025 found that the United States is on track to see 850,000 cases over the next 25 years at current vaccination rates.

“If vaccination rates decline further, case numbers could rise to 11 million over the next 25 years,” she wrote.

This scenario is not an inevitable outcome, of course. Another study suggested that the outbreak could be contained if stopped quickly, as long as 85% of the population is vaccinated against the disease.

Read more:
Measles could once again spread widely as cases rise around the world

4. Why do some parents choose not to receive vaccines?

A lot of ink has been spilled, digital and otherwise Discuss height to Vaccine hesitancy In the United States and the world. But the safe assumption is that parents around the world want the same thing: to keep their children as healthy as possible.

To explain how parents can reasonably weigh the risks posed by vaccines and the risks posed by a disease like measles and decide not to vaccinate, a public policy expert Y Tony Yang And a healthy economy I miss you At George Washington University, A A mathematical framework called “game theory”.

“Game theory reveals that vaccine hesitancy is not a moral failure, but simply a predictable consequence of a system in which individual and collective incentives are not properly aligned,” they wrote.

Read more:
Game theory explains why rational parents make vaccine choices that fuel outbreaks

5. Measles-free status

Measles is said to be eliminated from a country after at least 12 months, where internal spread of the disease is minimal and only small outbreaks are associated with international travel.

The World Health Organization announced on January 26 that the United Kingdom and five other European countries They lost their measles elimination statusAccording to Reuters. The organization’s Inter-American Office issued an alert on February 3, noting… A frightening spread of the disease Across North, Central and South America.

In November 2025, when Canada lost measles elimination status, she became a global health epidemiologist Catherine H. Jacobsen At the University of Richmond I noticed this The United States is likely to lose it in 2026in addition to Mexico.

Jacobsen explained why this classification is important for public health.

“The loss of measles elimination status is a symptom of a deeper problem: declining trust in public messages about science and health, which has led to lower vaccination rates and increased exposure to vaccine-preventable diseases,” she wrote.

Read more:
Canada is losing its official status as a measles-free country, and the United States will soon follow, with declining vaccination rates

This story is a summary of articles from the Conversation archives.