Vaccinated individuals account for approximately 3% of all measles cases reported this year, according to the Centers for Disease Control and Prevention (CDC).

Vaccinated individuals account for approximately 3% of all measles cases reported this year, according to the Centers for Disease Control and Prevention (CDC).

Getting a Second Dose of the Measles Vaccine May Not Always Guarantee Immunity

Some people who’ve received two doses of the measles vaccine are still contracting the disease this year, according to the Centers for Disease Control and Prevention (CDC). Approximately 3% of the nearly 1,200 measles infections in 2025 are in people who were fully vaccinated.

As of Friday, almost 40 cases of measles have been reported in fully vaccinated folks, with another 2% of cases in people who've had at least one dose of the vaccine. Many of these cases have been in Texas, which has seen a deadly outbreak of the highly contagious virus this year.

Last week, Texas reported its 21st confirmed measles case in someone who received two doses of the vaccine. The first 20 cases didn't lead to hospitalizations, according to Lara Anton, a spokesperson for the Texas Department of State Health Services. She didn't immediately respond to a request for more information about the additional case.

While the majority of measles cases occur in unvaccinated individuals, experts believe there are several factors contributing to the small percentage of cases in fully vaccinated people:

• High Transmissibility: Measles is incredibly contagious, making it easier for even fully vaccinated individuals to contract the disease if exposed during an outbreak.
• Waning Immunity: Although the MMR vaccine is highly effective, it doesn't offer 100% protection. With time, immunity may decline, making vaccinated individuals susceptible during intense outbreaks.
• Imported Cases: Resurgence of measles worldwide, particularly in Canada and Europe, contributes to increased exposure risk in the U.S. Even vaccinated populations can catch the disease from travelers who bring it into the country.
• Clusters of Unvaccinated Individuals: Measles tends to spread quickly in communities with low vaccination rates. Outbreaks in these areas increase the likelihood of breakthrough infections in fully vaccinated individuals.

The CDC recommends offering vaccination to people who have been exposed to measles within 72 hours of initial contact, if they are not fully immunized. If administered within this timeframe, the vaccine may provide some protection against infection or modify the clinical course of the disease.

Six cases of measles have also been reported in fully vaccinated individuals in Colorado. According to Hope Shuler, a spokesperson for the Colorado Department of Public Health and Environment, none of these cases required hospitalization.

Health authorities have urged seniors to get a measles booster, especially if they plan on traveling, as the vaccines used before 1968 may not offer as strong immunity as modern vaccines. Colorado has seen many of its vaccinated cases among residents who were exposed during travel, particularly to regions with large outbreaks like Canada and Europe.

The CDC has issued new guidelines for summer camps to prepare for the threat of measles spread. The guidelines include checking for documentation of immunity among staff and children to prevent the spread of the disease during camp activities.

Despite these measures, the U.S. is on pace to surpass the 1,274 cases of measles seen in 2019, and could see the greatest number of cases since the early ’90s. Alexander Tin is a digital reporter for our News based in the Washington, D.C. bureau. He covers federal public health agencies.

1. The CDC warns that even fully vaccinated individuals are still contracting measles this year, with approximately 3% of cases.
2. As of Friday, almost 40 measles cases in vaccinated people have been reported, with another 2% in those with at least one dose.
3. The highly contagious nature of measles is a factor, making it easier for vaccinated individuals to contract the disease during outbreaks.
4. Waning immunity is another issue, as the MMR vaccine doesn't offer 100% protection and immunity may decline over time.
5. Resurgence of measles worldwide, particularly in Canada and Europe, contributes to increased exposure risk in the U.S.
6. Outbreaks in communities with low vaccination rates also increase the likelihood of breakthrough infections in fully vaccinated individuals.
7. Health authorities recommend offering vaccination to those exposed to measles within 72 hours, if they are not fully immunized.
8. Six cases of measles have been reported in fully vaccinated individuals in Colorado, with none requiring hospitalization.
9. Seniors are urged to get a measles booster, especially if they plan on traveling, as older vaccines may not offer as strong immunity.
10. Many of the vaccinated cases in Colorado were among residents exposed during travel, particularly to regions with large outbreaks.
11. The CDC has issued new guidelines for summer camps to prevent the spread of measles during camp activities.
12. The U.S. is on pace to surpass the 1,274 cases of measles seen in 2019, and could see the greatest number of cases since the early '90s.
13. The financial industry, particularly the insurance sector, could be impacted by the increase in infectious diseases like measles.
14. Medicare and other healthcare financing systems may face additional costs due to the increasing number of cases.
15. Health and wellness in the workplace is a growing concern, with employers offering therapies and treatments for various medical conditions, including chronic diseases and respiratory conditions.
16. Digestive health and eye health are also key components of workplace-wellness programs, with a focus on preventive care and nutrition.
17. Science plays a crucial role in understanding the causes of diseases like measles and developing new vaccines and treatments.
18. Environmental science is another critical area, as climate change impacts air and water quality, which in turn can affect digestive, respiratory, and eye health.
19. Sleep is essential for overall health and wellness, with sleep deprivation linked to numerous health problems, including obesity, diabetes, and heart disease.
20. Fitness and exercise are important for maintaining cardiovascular health and managing weight, with many employers offering gym memberships or fitness classes as benefits.
21. Sexual health is another important aspect of health and wellness, with resources available for prevention, testing, and treatment of sexually transmitted infections.
22. Autoimmune disorders, neurological disorders, and skin conditions are common healthcare concerns, with a growing number of therapies and treatments available.
23. Mental health is a crucial component of health and wellness, with an increasing focus on reducing the stigma and increasing access to care for those suffering from depression, anxiety, and other conditions.
24. Men's health is a growing area of focus, with a focus on cancer, cardiovascular health, and mental health.
25. Women's health is another critical area, with a focus on reproductive health, breast health, and mental health.
26. Parenting is a challenging task, with a focus on child development, nutrition, and health, as well as mental health and stress management for parents.
27. Skin care is an important aspect of overall health and wellness, with a focus on preventing and treating various skin conditions.
28. Industry leaders in healthcare, retail, transportation, manufacturing, technology, and finance are working together to address these health concerns, with a focus on innovation, access, and equity in healthcare and wellness.

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