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Measles 101: What You Need To Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Dec 15, 2021.

Is Measles Still a Risk in the US?

A case of measles is only a plane flight away. In 2000, measles was declared eliminated from the U.S. However, in Dec, 2019 the CDC reported over 1,200 cases of measles over 3 dozen US states. This far surpasses the 2014 outbreak where 667 cases were reported during the entire year. In fact, the number of measles cases in 2019 were the highest since measles was eliminated in 2000.

As of Dec. 1, 2021 there have been 49 confirmed cases in 5 jurisdictions, per the CDC. Numbers in 2021 have been far lower than 2019, which is good considering the COVID pandemic.

The majority of people who contract measles today are unvaccinated, often as a result of the "anti-vaccination" movement wrongly declaring vaccines as unsafe, or due to personal or religious beliefs. The measles vaccine is one of the most effective vaccines ever developed.

  • Most Americans are protected against measles through vaccination, but not all. Many people are misinformed that the measles vaccine is unsafe.
  • If one person is contagious with the measles, 90% of those who come in contact with that person will get infected with the measles unless they are vaccinated.
  • When given appropriately, the required two doses of the MMR vaccine will prevent a case of measles 97% of the time.

How Does My Child Get Measles?

Measles, also known as rubeola, is a very contagious virus and is easily spread through the air when someone coughs or sneezes. One person who has measles may infect others when viral droplets spray into the air. The droplets can remain contagious on infected surfaces for up to 2 hours.

  • However, the measles vaccine is extremely effective and safe.
  • One dose of measles vaccine will prevent measles about 93% of the time; two doses are 97% effective.
  • Only about 3 out of 100 people who get two doses of measles vaccine will still get measles if exposed to the virus, and then the illness is probably less severe and less contagious.

Measles still commonly exists in other parts of the world, including areas in Europe, Asia, the Pacific, and Africa. But you don't have to leave the U.S. to contract measles. Outbreaks, like the one that originated in Disneyland in December 2014, and the one in 2019, can occur when unvaccinated adults or children get the measles (either in the US or from a foreign country) and then spread it to others. Measles can also be brought into the US by unvaccinated foreign visitors who contract measles in other countries.

What Are the Measles Symptoms?

A case of measles (also called rubeola) is fairly easy to identify.

Symptoms usually begin about 1 to 2 weeks after exposure to the virus and include:

  • fever (up to 104° F)
  • cough
  • runny nose
  • red, watery eyes.

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

The telltale measles rash usually breaks out on the third to fifth day. The spots start as a red, flat rash on the face and hairline and spread down to the neck, trunk, legs and feet. Raised areas on the spots may occur. The rash may or may not itch. After a few days, the fever subsides and the rash fades. However, complications can occur.

CDC: Measles Vaccine Recommendations, Children

CDC recommends all children get two doses of measles-mumps-rubella (MMR) vaccine, starting with the first dose at 12 through 15 months of age, and the second dose at 4 through 6 years of age (or at least 28 days following the first dose).

If you'll be traveling out of the country before your infant is one year old, talk with your pediatrician about getting the measles vaccine earlier for your child.

  • The CDC states that infants 6 to 11 months old traveling internationally get one dose of measles vaccine.
  • After this, they should get two more doses according to the routinely recommended schedule (one dose at 12 through 15 months of age and another dose at 4 through 6 years of age).

Children may also get MMRV vaccine, which protects against measles, mumps, rubella, and varicella (chickenpox). This vaccine is only licensed for use in children who are 12 months through 12 years of age.

CDC: Measles Vaccine Recommendations, Teens and Adults

Adults who do not have evidence of immunity should get at least one dose of MMR vaccine; however, certain adults may need 2 doses. Adults who are going to be in a setting that poses a high risk for measles or mumps transmission should make sure they have had two doses separated by at least 28 days. These adults include:

  • students at post-high school education institutions
  • healthcare personnel
  • international travelers

It won't be harmful to get revaccinated even if you have been previously. For those traveling internationally, your vaccine requirements may be different; check with your doctor.

You would be considered immune against measles if you have at least one of these:

  • written documentation of adequate vaccination
  • laboratory evidence of immunity
  • laboratory confirmation of measles
  • birth in the United States before 1957.

The CDC recommends that travelers to certain foreign countries obtain the measles vaccine if they have not been previously vaccinated or previously gained protection by having the measles. The vaccine will not only protect the traveler, but also those at home.

You can review the CDC Travel Notices on measles (and other diseases) prior to travel to see which countries have posted notice of measles outbreaks.

Is the Measles Vaccine Safe?

Most people have no reaction at all to the measles vaccine; 5% to 10% of recipients may get a rash or mild fever.

Research done by Kaiser Permanente over a 12 year period confirmed that the measles-mumps-rubella (MMR) and the measles-mumps-rubella and varicella (MMRV) vaccine are safe. In total, researchers looked at over 700,000 measles vaccine doses. The research was published in Pediatrics

  • In the study of children aged 12 to 23 months, children received the combination measles-mumps-rubella-varicella (MMRV) vaccine. Others were given separately administered measles-mumps-rubella and varicella (MMR + V) vaccines, but they received both vaccines on the same day.
  • The vaccines didn't increase the children's risk of seven types of neurological, blood or immune system disorders.
  • As shown in previous studies, fevers and febrile seizures are possible, but the risk is small; seizures occurred in less than one of every 1,000 vaccine injections.

Why is the Measles Vaccine Still Necessary?

If vaccinations for measles were stopped, measles cases could return to pre-vaccine levels. This is especially true for those who refuse vaccination for themselves or their children.

Prior to the vaccine program, an estimated 3 to 4 million persons in the U.S were infected each year. Of these, there were 48,000 hospitalizations, roughly 400 to 500 of these died, and 1,000 suffered encephalitis (brain swelling) due to measles.

Widespread use of measles vaccine has led to over a 99% reduction in measles cases in the U.S. However, foreign visitors to the U.S. and unvaccinated U.S. citizens who acquire measles from outside countries while traveling can infect unvaccinated people in the U.S. -- that's why a measles vaccine is still needed.

Isn't it Safer to Build a Natural Immunity?

Measles has no treatment once it occurs, and for most, measles will run its course with a full recovery.

Symptoms can be treated with acetaminophen (Tylenol) and plenty of rest. Do not use aspirin in children due to the risk of Reye's syndrome, a rare liver and brain problem.

Some people believe exposing their child to an illness is a better way to boost immunity than vaccination. However, some people may not realize these viruses can lead to serious complications, especially in children younger than 5 years of age.

  • Children with measles have been left blind or deaf.
  • As many as 1 out of every 20 children with measles gets pneumonia, the most common cause of death from measles in young children.
  • In about 1 out of 1,000 people, the measles virus can also move to the brain, causing a swelling of the brain (measles encephalitis), which can lead to brain damage or be fatal.
  • 1 or 2 out of 1,000 children with measles will die, even with the best care.

Weigh it up. Sore arm and slight fever from vaccination versus a risk to your child's life. Which do you choose?

Are Vaccines and Autism Related?

Some people claim there is a link between thimerosal-containing childhood vaccinations and the development of autism, but no properly conducted study has ever been able to back up these claims.

Thimerosal is a mercury-containing preservative that was commonly used before 2001 to prevent bacterial contamination. The quantities used were tiny and unlikely to be harmful. But many people have concerns about the use of any product derived from mercury, especially in their child.

Thimerosal was removed over 15 years ago from most vaccines recommended for children younger than six. Studies show that the number of autism cases did not decline after removal of thimerosal, suggesting that exposure to this agent is not a primary cause of autism.

Thimerosal is not present in any COVID vaccine used in the U.S. To see a full list of ingredients for COVID-19 vaccines in the U.S., follow this link.

Your Vaccination Protects Others, Too

Even though vaccines are available, worldwide in 2018 there were 140,000 measles deaths globally, mostly among children under the age of five, according to the latest World Health Organization (WHO) data. However, from 2000 to 2018, measles vaccination prevented an estimated 23.2 million deaths making the measles vaccine a highly effective public health tool.

"Herd immunity" has a lot to do with these positive results worldwide.

  • With "herd immunity", also called community immunity, you’re protecting yourself and your community when you get vaccinated
  • When enough people are vaccinated against a certain disease like measles, the virus can't be as easily spread from person to person — and the entire community is less likely to get the disease.
  • This is especially important for very small babies who may not be old enough to get vaccines, or other groups who cannot get a vaccine due to a medical concern.

For example, infants usually do not get their measles vaccine until they are one year old, and their immunity gained from the mother may wane even earlier. That's why it's so important for everyone to get their vaccine, to help protect those who cannot get the vaccine due to young age, severe allergy to the vaccine, cancer, or immunosuppression.

When people skip vaccines, the benefit from herd immunity gets compromised and infection rates from vaccine-preventable diseases rise.

Do Adults Need a Measles Vaccine?

It depends on their vaccine history. According to the CDC:

If you are an adult, you do not need the MMR vaccine if:

  • blood tests show you are immune to measles, mumps, and rubella,
  • OR you were born before 1957,
  • OR you have written documentation of adequate vaccination
  • OR you have laboratory confirmation of measles.

If you’re unsure whether you’ve been vaccinated, first try to find your vaccination records. If you do not have written documentation of MMR vaccine, you should get vaccinated. The MMR vaccine is safe, and there is no harm in getting another dose if you may already be immune to measles, mumps, or rubella.

People who were vaccinated prior to 1968 with either inactivated (killed) measles vaccine or measles vaccine of unknown type should be revaccinated with at least one dose of live attenuated measles vaccine. This recommendation is intended to protect those who may have received killed measles vaccine, which was available in 1963-1967 and was not effective.

Healthcare personnel born before 1957 without laboratory evidence of immunity or disease should consider getting two doses of MMR vaccine, separated by at least 28 days.

Check with your doctor to discuss. You can see CDC guidelines in more detail here.

In the States: The Measles Debate Gets Personal

As with COVID, the measles vaccine topic can be a hot debate topic in the US. In general, vaccination is becoming more and more controversial due to the spread of misinformation.

In 2015, the number of measles cases in the U.S. reached 189, with many cases linked to a Disneyland outbreak in California. From January 1 to December 31, 2019, 1,282 individual cases of measles were confirmed in 31 states.

Many people believe that vaccinating their child is a personal choice and chose not to vaccinate if they live in a state that allows nonmedical personal exemptions. In 2019, the measles outbreak in New York was declared a public health emergency. Many cases involved members of the Orthodox Jewish community.

On the other hand, some parents are distraught and worried that they cannot send their children to daycare or school if they are too young to receive the vaccine, or if they have an immune disease and cannot receive the shots. Many parents believe that those who do not vaccinate, the so called "anti-vaxxers", are in the wrong.

What Are the Vaccine Requirements for Schools?

No US federal vaccination laws exist across the board. The regulations surrounding vaccination for entrance to schools is solely determined by the states, and are subject to changes based on legislation.

All states require specific vaccines prior to public school kindergarten entrance. However, laws may exist to grant exemptions to children for medical, religous, or personal belief reasons.

Vaccination requirements are important tools for maintaining high vaccination coverage and low rates of vaccine-preventable diseases (VPDs). The Immunization Action Coalition provides a tool to view state information on vaccine requirements.

Always check on your individual state, local and territorial health depts., as well as school requirements for the latest vaccination updates. You can also check with your local pediatrician.

Finished: Measles 101: What You Need To Know

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.