An ongoing measles outbreak in the southwestern United States shows no signs of slowing as health officials strive to control its spread and increase vaccination rates. Given the current wave of misinformation regarding vaccines, experts in public health express concern that incidents like this may be more frequent in the future.
This outbreak initiated in late January, and by February 25, Texas had documented 124 cases, predominantly in Gaines County, while nine cases were reported in the nearby Lea County, New Mexico. A single death reported on February 26 marks the first measles fatality in the U.S. since 2015.
“The majority of cases are arising within a Mennonite community that predominantly homeschools, thus avoiding school vaccine requirements,” notes Bill Moss, MD, MPH, a professor in Epidemiology and executive director of the International Vaccine Access Center.
In this Q&A, he outlines essential information about measles, its transmission, and the cruciality of maintaining high vaccination rates to prevent outbreaks.
What is measles?
Measles is an extremely contagious illness triggered by the measles virus, often resulting in symptoms such as a cough, red eyes, high fever, and a rash. However, it can also lead to more severe health issues.
Is measles dangerous?
Absolutely. In the United States, roughly 1 in 5 unvaccinated individuals will need hospitalization due to measles. In 2024, this number was even greater—around 40% of measles cases resulted in hospitalization. Measles may also cause severe complications, including pneumonia, encephalitis, brain damage, and complications during pregnancy. Individuals can experience complications from measles, even those who are otherwise healthy.
Research indicates that measles can eliminate the body’s immune memory against other bacteria and viruses, thus impairing the immune system and increasing susceptibility to various illnesses. This vulnerability can persist for several years.
Measles can also be fatal. In 2023, approximately 107,500 fatalities from measles were recorded globally, predominantly among unvaccinated or under-vaccinated children under five years old.
How does measles spread?
Measles is transmitted through airborne viruses and droplets. One can contract measles by inhaling air contaminated by an infected individual or by contacting contaminated surfaces. The virus can linger in the air for several hours post-cough or sneeze from an infected person, meaning close proximity is not necessary for transmission.
Measles ranks as one of the most contagious diseases. In an entirely susceptible population, one individual with measles will infect an average of 12 to 18 others.
Who is at the highest risk for contracting measles?
Individuals who have not received two doses of the measles, mumps, and rubella (MMR) vaccine or have not previously contracted measles are at risk.
This includes many children under 12 months old in the U.S., prior to their first MMR vaccine dose. Moreover, certain individuals cannot receive the MMR vaccine due to specific medical conditions, severe allergies, or being immunocompromised, as well as pregnant individuals or those planning to become pregnant soon.
At what age should my child get the MMR vaccine?
The first dose of the MMR vaccine is recommended in the U.S. at 12 to 15 months of age. This dose offers protection to approximately 93% to 95% of children. A second dose is advised at ages 4 to 6 years, typically just before heading to kindergarten, with around 97% of children fully protected after this second dose.
Can a child get the MMR vaccine earlier than 12 months old?
The MMR vaccine can be administered to children as young as 6 months. The CDC advises that young children aged 6 to 11 months should receive the vaccine before international travel, but does not offer explicit guidelines for outbreaks in the U.S. An MMR vaccine given during this age range is in addition to the two routine doses, not a substitute.
If you reside in or plan to travel to a region experiencing an outbreak, consult your pediatrician regarding the possibility of your young child receiving a dose of the MMR vaccine outside of the standard schedule. This may also pertain to children who have received their first recommended MMR dose but have not yet reached the appropriate age for the second dose. As per the CDC, the second dose can be administered earlier if at least 28 days have passed since the first dose. Your healthcare provider can assist in assessing any factors that might enhance your child’s risk of measles exposure, including local measles activity and vaccination rates.
If the measles vaccine is so effective, why do I still hear about cases of measles?
The issue lies in insufficient vaccination coverage. Due to its highly contagious nature, measles requires that at least 95% of a community is vaccinated. In the U.S., approximately 91% of children aged 19 to 35 months have been vaccinated. However, in some communities, vaccination rates are significantly lower, resulting in heightened risk.
Why have U.S. measles vaccination rates dropped in recent years?
There are various interrelated factors; one significant reason is the effectiveness of previous vaccination efforts. Successful immunization programs can inadvertently lead to decreased fear of diseases as they diminish their prevalence, causing some parents to question the necessity of vaccinating when they perceive a lower risk.
Every parent aims to make the best decisions for their child. With historically low instances of measles within the U.S. and the rise of misinformation regarding childhood vaccines, some parents may underestimate measles risks and overrate the vaccine’s dangers.
How long after vaccination does it take to build protection?
After receiving the MMR vaccine, your body requires time to develop antibodies that provide defense against potential exposure to the virus. Generally, it takes about two weeks to reach full protection.
Did I receive lifelong protection after measles vaccinations as a child?
While most individuals vaccinated against measles maintain lifelong immunity, not all do, and the likelihood of enduring protection increases with a second vaccine dose. Those who respond to the measles vaccine are presumed to have lifelong immunity, as there is no indication of loss of this protection over time.
Adults vaccinated for measles between 1963 and 1968 should verify their vaccination records, as a less effective inactivated virus vaccine was available during that period and was later discontinued. This affected only a small fraction of the current population, approximately 600,000 to 900,000 individuals in the U.S.
How can I determine if I am protected against measles?
Your best approach is to review your vaccination history. If you lack access to record documentation and cannot remember if you were vaccinated, the easiest option is to receive another dose. Getting an additional dose of the measles vaccine is safe, even if you’ve previously been vaccinated or naturally immune from an earlier infection.
Generally, older adults born before 1957 are considered to possess natural immunity since they likely encountered measles before vaccines were available.
Blood tests exist to detect antibodies to the measles virus. These tests are particularly useful for immunocompromised individuals or those unable to receive the MMR vaccine. They are also frequently administered to ensure that healthcare workers are properly protected, especially in pediatric wards or areas at higher risk for measles exposure.
Is it safer for children to contract measles from another child than to receive the measles vaccine?
No. Measles is a perilous disease, and the vaccine is considered very safe. The potential risks of severe illness, death, or lasting complications from a measles infection significantly outweigh the mild side effects that may accompany vaccination. Serious reactions to the MMR vaccine are infrequent.
Where can I obtain a measles vaccination?
Measles vaccinations are available at doctors’ offices, clinics, and government health centers. In areas experiencing outbreaks, local health departments may provide additional MMR vaccination opportunities aimed at enhancing community protection. For more information, contact your local or state health department.
How can I stay updated on measles activity in my area?
The CDC’s website serves as a valuable tool for monitoring national trends and outbreaks. State health departments that report to the CDC are also good resources. In states with ongoing outbreaks, local health agencies may issue more frequent updates to alert communities about active cases and recommend appropriate safety measures and resources.
Measles is one of the most contagious infectious diseases. It is also preventable through vaccination.
Where can I find additional information about measles?
For more details, visit the CDC’s pages regarding measles and vaccination. The WHO also provides a fact sheet that outlines global impacts related to the virus.
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Editor’s Note: This content is not intended as a substitute for professional medical advice, diagnosis, or treatment, and it does not constitute medical or other professional guidance.
