Measles 2025

 You may have heard the term herd immunity.

This is my best way to describe what we are talking about.

Imagine a forest. After a rainstorm, the trees are moist. A spark is unlikely to cause much damage. If the trees are dry and brittle, that same spark can cause a raging inferno quickly.

People who are unvaccinated are like dry trees. The more of them there are, the more danger there is of more damage to the surrounding area. If the fire is strong enough, even some wet trees don’t stand a chance. Some people (such as babies, and people with cancer or other immune compromise) can’t be vaccinated, and can’t help but be a ‘dry tree’.

Herd immunity is when at least 95% of people have the vaccine-induced protection.

We shouldn't need to be writing this post! Measles was eliminated in the US in 2000. It is horrible to see the news about the current rise in cases.

Measles, also known as rubeola, is very contagious

This virus is so virulent that ninety percent of unvaccinated people will catch this virus once they are exposed. What is even more alarming is that it can remain on surfaces or even in the air for 2 hours after someone has sneezed or coughed! If someone travels on a plane while they are contagious...that is a potential nightmare. One of the reasons that it spreads so easily is that people are contagious as early as 2-4 days prior to showing any signs of the virus and may remain contagious until the rash is gone, or 4 days after the symptoms are all clear.

How the measles rash spreads on the body

The measles rash follows a characteristic head-to-toe spread.

1. Incubation Period (7–14 days after exposure)

• The measles virus enters through the respiratory tract and replicates in the local lymph nodes.

• It then spreads through the bloodstream to various organs, including the skin.

• No symptoms appear during this phase.

2. Prodromal Phase (Days 1–4)

• Before the rash appears, the child develops high fever (up to 104°F), cough, runny nose, and red eyes.

• “Koplik spots” (tiny white spots on the inner cheeks) sometimes appear 1–2 days before the rash.

3. Rash Stage (Days 4–10)

The rash appears as red, blotchy spots that spread in a predictable pattern.

Day 1: Face and Neck

• The first spots appear around the hairline, forehead, and behind the ears.

• The rash spreads downward to the neck and upper chest.

Day 2: Torso and Arms

• The rash extends to the trunk, upper arms, and thighs.

• Individual spots start merging, forming confluent patches.

Day 3: Lower Body and Extremities

• The rash spreads to the lower legs and feet.

• By this point, most of the body is covered.

4. Recovery (Days 6–10)

• The rash starts to fade in the same order it appeared (face first, then torso, then legs).

• As it resolves, it leaves behind a brownish discoloration and fine skin peeling.

If you have a happy child with a rash, our guess would be that it isn’t measles. People with measles will look sick and likely have a high fever. The rash will not be one of the first symptoms.

Complications are frequent

They range from ear infections to pneumonia, encephalitis and/or seizures. 1 in 5 people are hospitalized after infection (roughly 1 in 4 when just looking at kids), often with pneumonia or brain swelling. 1-3 out of every 1,000 cases are fatal. Take a moment and reflect on what that means. This is a serious illness. This is not one of those illnesses to wish your child would catch in order to get natural immunity.

Vaccination

The routine measles vaccine is combined with mumps and rubella and is referred to as the MMR. The individual components have not been available separately for many years. The first MMR shot is routinely given to patients between 12-15 months and again between 4-6 years.

Why do we wait so long before giving that first MMR protection to babies?

Assuming that the birth mom has been fully vaccinated (or less likely has had the actual measles) infants are born with passive immunity to the disease. This immunity starts to wane and is considered mostly gone by the time the babies are between 12 and 15 months. If a child is vaccinated when they are younger than a year old and still have some maternal protection, the vaccine does not seem to be as effective for long term protection.

For the second dose there is the option of combining it with the chickenpox vaccine called Varivax. That combo vaccine is called Proquad or MMRV.

Just one dose of the MMR vaccine is thought to be 93% effective. The second dose is given just to catch the occasional person who didn't get effective immunity from one dose and bumps the effectiveness up to 97%. It can be given earlier than 4 years, but I am not too concerned about the timing of the second dose as long as patients have gotten the first one.

If you are traveling to a high risk area, the CDC will suggest getting the second shot early. The 2 shots simply need to be given at least 28 days apart and after the age of 1 year.

The MMR is a live vaccine and it is true that in some rare cases the reaction can be a little rough. Interestingly, most kids are just fine the day of the immunization. Typically the reaction comes along between 7-21 days after the shot. This reaction may include high fever and rash. This is not thought to be contagious. It usually lasts only a day or so.

Kids with severe egg allergies don’t need to worry about the MMR vaccine. Even though the vaccine is made using chick embryo cell cultures, it doesn’t actually contain significant egg protein. Studies have shown that even kids with a history of anaphylaxis to eggs can get the MMR safely without any extra precautions. The only vaccines where egg allergy is a concern are some flu vaccines and the yellow fever vaccine (which isn't routine anyway).

Before routine use of the measles vaccine, there were about 500,000 cases of measles in the United States each year, and about 500 deaths. Measles also led to about 48,000 people being hospitalized and another 1,000 people being left with chronic disability from measles encephalitis. Study after study has shown that there is no link between the MMR and autism, but there are still some folks reluctant to give their children the vaccination.

In July 2016, SB277 was signed into law. It is now a requirement that all children attending schools in California have the measles vaccine unless they have a medical contraindication. Since the law passed, I have seen a steep increase in vaccination rates. This law probably has saved lives.

Most schools just require 2 doses after the age of a year and don't care a bit about the timing.

Outbreaks

The CDC defines an outbreak as “a chain of transmission that includes 3 or more cases linked in time and space.” As this post is written, in February of 2025, the numbers are increasing. We are seeing an outbreak in a rural pocket of unvaccinated children in Texas. The CDC is currently updating its page monthly, so it is challenging for us to give you exact numbers. If you’re traveling to the South, check the local news sources before you go.

Travel considerations

Unfortunately, measles remains a common disease in many parts of the world. Each year, an estimated 128,000 people die from measles. Take a moment to recognize what a huge number that is! Quite a few countries and popular travel destinations have experienced measles outbreaks in recent years, including countries in Europe, Israel, India, Thailand, Vietnam, Japan, Ukraine, and the Philippines. This is only a partial list. Before your next trip, check your destination and CDC’s global travel notices.

If you do travel, pay attention to your health for 3 weeks after you return to make sure you didn’t bring this home.

Infants can get the vaccine early for travel or exposures

If you are traveling to a high risk area or there has been a possible measles exposure, the vaccine can be given as early as 6 months. You need to be aware that this early shot can’t be counted on for lasting protection. Your child will still require two shots after the first birthday. Your insurance company also might refuse payment if the shot is given outside of the routine schedule, but this is less likely if your doctor “codes” for the shot to be given due to travel or exposure.

If your child is over a year and has had only one MMR so far, go ahead and see about getting them their second shot early if you are going to one of the higher risk countries (or Texas).

It takes about 10-14 days to get any significant protection from the first MMR. Hence planning is important.

Hepatitis A is one more vaccine that can be given early for travelers.

Several years ago when I was working on my very first measles post, one of my adult friends said to me, "We all got measles and survived, what is the big deal?" My response was, "It is true enough that the vast majority of folks who get measles will recover intact and have lifelong immunity. However, one to three kids out of 1,000 will die; many more than that will be permanently harmed. That is too many when we are talking about something that can be prevented. That 1 child out of 1,000 matters."

Remember, that babies are vulnerable “dry trees.” We all need to do our part to keep them safe.

Extra note for adults - depending on when you were born, your original vaccination may or may not be still providing protection. You may have been given only 1 shot, a one time common practice; you may have been given an inactivated virus shot, which was also a long ago common practice; or if you were inoculated in the 1960s, you may have been given a relatively ineffective vaccine because of now-known manufacturing problems. The best way to make sure is to have your titers measured, or you can do what I just did since we will be traveling internationally later this year, and simply get a booster. Talk to your doctor about the best option for you.