Measles Vaccine: Schedule, Safety and Why It Matters

While some people think measles is just a rash and fever that go away in a few days, it can lead to serious health problems. Children younger than 5, adults older than 20, pregnant women and people with a weakened immune system face the highest risk of severe illness.  

Common complications include ear infections and diarrhea. More severe cases can result in pneumonia, encephalitis (swelling of the brain) or blindness. In rare cases, measles can be fatal.  

Health experts say the recent rise in measles cases reflects gaps in community immunity. In some areas, childhood vaccination rates have fallen below the level needed to prevent outbreaks, leaving clusters of people vulnerable to infection.

Because measles is so contagious, it does not take a large drop in immunization coverage for outbreaks to occur. Global travel and large gatherings can also contribute to outbreaks by increasing opportunities for exposure.

Physicians emphasize that maintaining high vaccination rates is the most effective way to prevent outbreaks and protecting vulnerable populations. 

“Vaccines are safe and they work,” Dr. Shalauta says. “Parents need to consider the benefits of vaccines and how they outweigh perceived risks.” 

The measles vaccine provides strong protection: 

One dose: About 93% effective 

Two doses: About 97% effective 

Health experts recommend two doses for long-lasting immunity. 

Because no vaccine is 100% effective, rare breakthrough infections can occur. However, people who contract measles after vaccination typically have milder symptoms and are less likely to spread the virus to others. 

Scripps follows immunization guidance from the West Coast Health Alliance, the California Department of Public Health and the American Academy of Pediatrics. 

Children should receive two doses of the measles vaccine: 

First dose: 12 to 15 months of age 

Second dose: 4 to 6 years old (before school entry)  

Following the recommended measles vaccine schedule provides strong, long-lasting protection. High vaccination rates also help protect infants under 12 months and others who cannot be vaccinated.  

Daniel Lichtmann, MD, a pediatrician at Scripps Clinic Carmel Valley, agrees. “The only safe and effective way to truly protect yourself from the virus is through vaccination,” he says. “For anyone who cannot receive the vaccine for medical or age reasons, the best and safest approach is to vaccinate those around them.” 

Two doses of the measles vaccine have been recommended since 1989. Most adults who received one dose before that time are still considered protected.  

However, two doses are recommended for certain groups, including: 

• Health care workers 
• International travelers 
• College students 
• People at higher risk of exposure 

Some adults born between 1963 and 1967 may need a booster because they may have received an earlier, less effective version of the measles vaccine. If you were vaccinated in the 1960s and are unsure which vaccine you received, reimmunization is considered safe.  

Most people born before 1957 are generally considered immune due to prior exposure to the virus. 

If you’re uncertain about your measles immunity, check your vaccination records or talk with your health care provider.

The measles virus spreads through respiratory droplets when someone coughs or sneezes.  The virus can linger  in the air or on surfaces for up to two hours.  

If diagnosed with measles, public health guidelines advise isolating at home for four days after the rash begins, as people with measles remain contagious during this time.

Prevention steps include:  

• Covering your mouth and nose with tissue when coughing or sneezing and putting used tissue in the trash can 
• Washing your hands frequently with soap and water 
• Avoiding shared drinks or utensils 
• Disinfecting commonly touched surfaces, such as toys, doorknobs, tables and counters 

Early on, measles symptoms often resemble the flu or a cold.  

They may include: 

• Cough 
• Runny nose 
• Fever 
• Red, watery eyes 

Two to three days after symptoms begin, tiny white spots may appear inside the mouth.   

The telltale measles rash typically develops  three to five days after the first symptoms. It begins as flat red spots at the hairline and spreads downward to the face, neck, trunk, arms and legs.   

If you think  you or your child has measles or was exposed, call your doctor first. Do this before visiting a clinic. 

“Your doctor will determine if you are immune to measles based on your vaccination record, age and lab evidence,” Dr. Shalauta says. “Your doctor can also make special arrangements to evaluate you without putting other patients or medical office staff at risk.”

If symptoms develop after international travel, stay home and call your doctor right away.  

Before the measles vaccine became available in 1963, the virus was widespread in the U.S., infecting millions each year and causing significant hospitalizations and deaths. Routine vaccination led to a sharp decline in cases, and by 2000 measles was declared eliminated, meaning it was no longer spreading continuously within the country. 

In recent years, however, measles cases have increased both globally and in the U.S. Most cases are linked to international travel and occur in communities with lower vaccination coverage. Periodic outbreaks, including larger resurgences in 2024 and 2025, show how quickly measles can spread when fewer people are protected. 

These trends highlight the continued importance of maintaining high vaccination rates to prevent outbreaks and protect public health.

The measles vaccine has been extensively studied for decades and has a strong safety record. 

Still, some parents worry about a possible link between vaccines and autism, a claim that stemmed from a small 1998 study involving 12 children that was later discredited and fully retracted.

That misinformation has fueled vaccine hesitancy, leading some parents in certain states to seek personal-belief exemptions rather than follow recommended immunization schedules.

Health experts say scientific evidence is clear.

“Research has confirmed that vaccines do not cause autism,” Dr. Shalauta says. 

Vaccinations, including the MMR vaccine, are available at Scripps primary care offices and Scripps HealthExpress walk-in clinics throughout San Diego County.

Talk to your doctor or visit at nearby HealthExpress location to review your vaccination status and receive recommended vaccinations.