Over the past few years, there has been a resurgence in measles cases in the United States. This is due at least in part to a growing rate of vaccine hesitancy, which existed before COVID but certainly ramped up in the years since.
The best way to protect yourself or your child from measles is to get vaccinated. But because the first dose typically isn’t administered until a child is 1 year old, parents understandably have questions.
What does measles look like?
Measles is a viral illness. Individuals who are infected with it develop symptoms an average of two weeks after exposure. The symptoms begin with several days to a week of fever, fatigue, loss of appetite, cough, and runny nose. There may also be conjunctivitis or eye sensitivity.
After several days, a rash develops. It may begin with a rash of elevated white or grayish lesions on the inside of the cheeks, called Koplik spots, which look like grains of salt on a red background. Not all patients get the spots, but all patients develop the characteristic measles rash (pictures here).
The extent of the rash varies with the severity of the illness. During the period of the rash, children generally have a high fever, runny nose, and respiratory distress. Improvement tends to begin 48 hours after the rash appears, and the rash is gone within six or seven days. These symptoms may sound like standard childhood virus symptoms, but as I discuss more below, in some cases they can progress to be more serious or fatal.
How serious is measles infection?
Most of the time, children with measles are sick and then recover well. However, the disease can lower your immunity to other viruses — and also be extremely serious or fatal.
In developing countries, estimates put the measles fatality rate at around 2.2%. This means that of 100 people who are infected, 2 of them are expected to die. Fatality rates in settings with more resources, like the U.S., are lower but still higher than people might think (perhaps 1 in 1,000).
Most measles deaths result from pneumonia or neurological complications. In an estimated 1 out of 1,000 cases, encephalitis occurs. These symptoms include fever, headache, stiff neck, and coma. In 15% of those cases, death occurs.
Children (or adults) with immunodeficiency are at greater risk for serious complications. Pregnant people who become infected with measles are also at higher risk for complications, including pneumonia, brain swelling (in the pregnant person), and low birth weight, miscarriage, and other complications. These are most heavily documented in resource-poor settings, but pregnant people in the U.S. who become infected with measles should be in close communication with their doctor to monitor for serious infection.
How contagious is measles, and how does it spread?
Measles is extremely contagious. In an unvaccinated individual who hasn’t had measles and is exposed to it, the risk of infection is estimated at 90%. Transmission occurs with close contact with others, and also through the air. Measles virus in airborne droplets can stay alive for up to two hours. That is a long time! If someone with measles is in a room and then two hours later you arrive, you could get measles.
Individuals are contagious starting a couple of days before having symptoms and up to four days after the rash appears.
As a result of the long infectious period, the fact that the virus lives in the air for a long time, and the fact that nearly everyone who is exposed to measles gets it, measles spreads fast. Estimates suggest that in a totally unvaccinated population, each infected person will infect 12 to 18 other people. It is much more infectious than something like the flu, or COVID, where this number would be more like two. (By contrast, in a highly vaccinated population, the transmission rate would be close to zero.)
That said, if you’re vaccinated and exposed to measles, it’s rare that you would pass along the disease to someone else.
Are there treatments for measles?
There is no direct antiviral treatment for measles (nothing like Tamiflu for the flu, for example). Supportive care (medication for fever, fluids, treating any bacterial infections that arise as a result) is the main standard of care.
The other common intervention is vitamin A. In developing countries, high doses of vitamin A have been shown to reduce mortality in young children. There is limited evidence on the use of this treatment in developed countries, but it is standard practice to use it for children in the U.S. hospitalized with measles, due to the possibility that it would help and its limited downsides. It is important to note that the dosing protocol is very specific for this — it would not be appropriate to dose yourself with a lot of vitamin A, and the vitamins would be delivered directly, not through cod-liver oil or other foods.
How safe and effective is the vaccine?
Given that measles makes people sick and can kill them, spreads incredibly fast, and has limited treatments, it is very lucky that we have a vaccine. The existence of the vaccine is why people do not generally know as much about measles as they do about other illnesses.
This vaccine was first developed in the 1960s and has been used continuously. It is given in two doses, the first between 12 and 15 months and then a second at age 4. The vaccine is very effective. An estimated 95% of children develop antibodies in response to the first dose of the vaccine; 99% are responsive by the second dose.
That’s the big picture. Some follow-up questions:
Can I vaccinate my baby early? During a measles outbreak or if you’re planning international travel, it may be possible to vaccinate your child early — sometime after six months but before a year. If you do this, you will also need a dose between 12 and 15 months and another at age 4 (so, three total rather than two).
Should I get my child’s second shot early? Most children respond to the first shot of the vaccine, so there is no strong reason to get the second shot early. There is also not a strong reason to delay it, so if you are in an area with an outbreak, it may be appropriate to ask your doctor about moving up the shot in case your child is among a small group who did not respond to the first dose.
What should I do if I am pregnant, breastfeeding, or trying to conceive? We have some good evidence that the majority of vaccinated pregnant people pass antibodies on to their fetuses. Breast milk may pass some on as well, but not at the level of vaccination and there’s not strong data to support this as a means of protection. If you’re trying to conceive, you may want to ask your doctor about checking your antibody levels before getting pregnant.
Do I need a booster dose? Generally, no. Childhood vaccination provides lifelong protection. If you are immunocompromised and live in an outbreak area, you could ask your doctor about a booster. If you did not get vaccinated as a child and have not had measles, you should get vaccinated now.
Do measles vaccines cause autism? No, they do not. This is a fraudulent and debunked claim. There is ample evidence of no link between vaccines and autism.
How worried should I be about the current measles outbreaks?
Because measles is so contagious, we need to have an extremely high vaccination rate across the population in order to avoid outbreaks. Unfortunately, in recent years in the U.S. (and worldwide), vaccination rates have fallen and outbreaks have increased. In all of 2024, there were 16 measles outbreaks (defined by the CDC as three or more related cases) and a total of 285 documented cases of measles. As of March 2025, there have been three outbreaks with a total of 301 documented cases (there is a large outbreak in Texas).
From a public health perspective, the resurgence of measles is a significant concern. Whether you should personally be concerned about your health depends somewhat on circumstance.
If you are a fully vaccinated adult or a fully vaccinated child, there is little reason for concern about your personal health. The vaccine is protective.
If you are a parent of a child who is too young to be vaccinated, it is a concern if you are planning significant travel or if you are living in an area with a current outbreak. This is the circumstance in which you might consider early vaccination.
If you are the parent of a child who is over 1 and you’ve been hesitating on the vaccine, please take this as a nudge to vaccinate your child, to protect them and others.
The bottom line
- Measles is a viral illness that typically causes fever, fatigue, cough, runny nose, respiratory distress, and a rash. It usually improves within a week but can lead to serious complications.
- Most of the time, children with measles are sick and then recover well. The disease can lower one’s immunity to other viruses, though — and also be extremely serious or fatal. It is highly contagious.
- There is no direct antiviral treatment for measles. In the hospital, children are often treated with high doses of vitamin A. However, the dosing protocol is very specific and is administered by a doctor. It would not be appropriate to dose yourself with a lot of vitamin A, and the vitamin would be delivered directly, not through cod-liver oil or other foods.
- The measles vaccine is safe and extremely effective at preventing measles. It is given in two doses, the first at around one year. During a measles outbreak or if you’re planning international travel, it may be possible to vaccinate your child early.
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My son got the first shot. For the second shot, “it may be appropriate to ask your doctor about moving up the shot in case your child is among a small group who did not respond to the first dose.” How do you know they haven’t responded do the first dose. What does that mean? Thanks!
I’ve heard that the reason vitamin A is helpful in developing countries is because it’s actually just treating previously-existing vitamin A deficiencies that are common in less developed countries, and that are exacerbated by measles. And this is why what evidence there is in the US doesn’t really show any benefit – we mostly don’t have a problem with vitamin A deficiency here. Ultimately it’s not treating the measles in any way.
Do we have any data about any immunity passed through breastfeeding for babies under a year? I have a 4 month old and have a family international trip (to Mexico) coming up, and I’m concerned about the air travel, but wondering if breastfeeding my daughter is conferring any sort of protection at this point.
Also – do we know whether masking is effective against measles? I don’t think I’d be able to keep a mask on my baby safely, but I’m just curious if there are any risk reduction strategies we can take until she can be vaccinated. Thanks!
Came here to ask the same question! Also planning a direct flight to Mexico with my kids in a couple months–second kid will be 4 months by then. I feel like there’s not much guidance on how to protect kids under 6 months so too young to get the vaccine even on an early schedule. For example, should I get a booster and hope that might pass along some protection through breastfeeding? My OB seemed skeptical that my immunity from having been vaccinated as a kid would confer much protection to this baby. Also, my OB recommended my parents get boosters before coming to visit the baby because they’re in their early 70s and can’t remember if they ever even had measles as a kid and even if they did it’s possible they no longer have immunity so many decades later–does that seem like a good idea?
Wouldn’t hurt for them to get an MMR top up. Before I was pregnant my preliminary bloodwork has my Rubella anti-bodies low so I did a booster, and I’d had all my shots.