The Measles Vaccine: How It Changed the Course of Public Health

For decades, measles was one of the most feared childhood illnesses—not just because of how contagious it is, but because of how quickly it could spiral into something dangerous. High fevers, severe rashes, and a risk of long-term complications made this disease a public health crisis around the world. But today, many people in the U.S. can go through their entire lives without knowing someone who has had measles—thanks largely to a vaccine developed over 60 years ago. That said, the disease has recently made headlines again, with 712 confirmed cases across 25 states as of April 10, 2025. 

Before the Vaccine: The Era of Measles Epidemics

For much of the 20th century, measles was a common—and often serious—illness in the United States. Nearly every child contracted it by the age of 15. While most survived, thousands were hospitalized, and hundreds died each year from complications like pneumonia or encephalitis (brain swelling).

In fact, before the vaccine became available:

• Nearly 3 to 4 million people in the U.S. were infected with measles each year
• 48,000 required hospitalization annually
• 400 to 500 measles-related deaths occurred each year
• 1,000 developed long-term disabilities due to measles-related brain inflammation

This widespread burden meant that preventing measles wasn’t just a health priority—it was a national goal.

The Discovery That Changed Everything

The development of the measles vaccine began in earnest during the 1950s. Scientists knew that the virus was highly infectious, so any attempt to control it would need to be extremely effective.

Dr. John Enders, a medical researcher who had already contributed to the development of the polio vaccine, played a central role. In 1954, Enders and his team successfully isolated the measles virus from an infected child—David Edmonston. This “Edmonston strain” would become the foundation for future vaccine development.

By 1963, the first licensed measles vaccine was introduced in the United States. It was a killed-virus vaccine, developed by Dr. John Enders and Dr. Thomas Peebles. However, it was soon replaced in 1968 with a more effective and longer-lasting live attenuated vaccine—the version that is still in use today (with updates and improvements).

How the Measles Vaccine Works

Unlike some illnesses where immunity fades over time, the measles vaccine has proven to offer long-lasting protection with just two doses.

The current vaccine is a live attenuated virus—meaning the virus is weakened so it can’t cause illness in healthy individuals but still triggers the immune system to build a strong defense. It’s commonly given as part of the MMR vaccine, which protects against measles, mumps, and rubella.

Here’s how it works:

• First Dose: Given at 12–15 months of age
• Second Dose: Given at 4–6 years old
• Effectiveness: One dose is about 93% effective; two doses are about 97% effective

Because the measles virus is so contagious, achieving high levels of vaccination across communities is essential for something called herd immunity. For measles, this threshold is high—around 95% of the population needs to be vaccinated to prevent outbreaks.

A Look at Vaccine Safety and Monitoring

Since its introduction, the measles vaccine has undergone decades of monitoring and improvement. Today, it’s considered one of the safest vaccines available, with a strong record of success and minimal risk for side effects.

Common side effects are typically mild and may include:

• Soreness at the injection site
• Mild rash
• Fever

Serious side effects are extremely rare. The Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) have safety monitoring systems in place, including the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD), to track any issues and ensure ongoing vaccine safety.

Over 60 years of use and surveillance have reinforced the measles vaccine’s safety profile, making it a cornerstone of modern preventive healthcare.

Measles Makes a Comeback: What’s Causing the Resurgence?

Despite the vaccine’s long history of effectiveness, measles cases have been increasing in recent years—not just in the U.S., but globally. Several factors are contributing to this resurgence.

Decreased Vaccination Rates

As vaccination rates drop in certain communities due to vaccine hesitancy or lack of access, herd immunity weakens. Even small pockets of unvaccinated individuals can allow the virus to spread rapidly.

International Travel

Measles is still common in some parts of the world. Travelers who visit areas with ongoing outbreaks can bring the virus back home, where it can spread in communities with low vaccination coverage.

Increased Misinformation

Misinformation about vaccine safety—particularly online—has also played a role in eroding public trust. Even though the science supporting vaccine safety is clear, fear and confusion can impact decision-making.

It’s a reminder that while medical science has come a long way, public health depends on continued education, access, and trust.

From Single Shot to Standard Care: The Rise of the MMR Vaccine

The MMR vaccine—offering protection from measles, mumps, and rubella—was introduced in 1971. It streamlined vaccination efforts by bundling protection against three serious illnesses into one shot. Over the years, it became a standard part of pediatric care.

By the early 1980s, two doses of MMR were routinely recommended, and measles cases plummeted.

• In 2000, the United States declared measles eliminated—meaning there was no continuous disease transmission for over 12 months.
• But elimination doesn’t mean eradication. Measles can still be imported and cause outbreaks in under-vaccinated areas.

This illustrates the importance of maintaining high coverage rates and ongoing vigilance, even when the disease seems like a thing of the past.

Key Takeaways from Measles Vaccine History

Here’s a quick snapshot of how the measles vaccine has shaped public health:

 Milestones

• 1954: Virus isolated by Dr. Enders
• 1963: First vaccine licensed
• 1968: Improved live attenuated vaccine introduced
• 1971: MMR vaccine developed
• 1989: Second dose recommendation added
• 2000: Measles eliminated in the U.S. 

Vaccine Successes

• Millions of cases prevented
• Drastic reductions in hospitalizations and deaths
• Long-term protection with minimal side effects 

Today’s Challenges

• Rising cases linked to vaccine hesitancy
• Increased global travel
• Need for continued education and access 

Learning from the Past to Stay Prepared

The measles vaccine is more than a medical breakthrough—it’s a public health success story built on decades of research, testing, and global cooperation. But like all success stories, it requires effort to maintain. Understanding its origins, appreciating its safety and efficacy, and staying informed can help people make confident choices when navigating their own healthcare.

It’s also important to remember that health decisions often come with questions—and those deserve thoughtful, respectful answers. No matter where you stand on the issue, staying informed and connected to trusted medical resources is one of the best ways to protect yourself and your family.

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