In this article a clinical infectious diseases pharmacist reviews five things for pharmacists to know about measles in 2025.
Authored By: Timothy P. Gauthier, Pharm.D., BCPS, BCIDP
Article posted 8 March 2025
This week on Tuesday night a few text messages came through on WhatsApp chats about how there was a measles case from a high school student here in the Miami. Although I have practiced in the area of infectious diseases pharmacy for quite a while now, measles has not been of much clinical relevance to me beyond MMR for routine vaccination. Now with measles in the area, it was time to learn more about it.
Following some readings from WHO, CDC, Pubmed, and others, I developed more perspective on how measles outbreaks can be relevant to pharmacists. There are many great resources out here but I had to go to a bunch of different web pages to get the information in this article. Hopefully placing some of the key information here in one place will help others brush up on things for pharmacists to know about measles in 2025.
First some basics
Measles is also referred to as rubeola, 10-day measles, or red measles. It is caused by a single-stranded, enveloped RNA virus with serotype 1 and a member of the genus Morbillivirus in the Paramyxoviridae family. It is highly contagious and causes a distinct red rash that spreads from the head to the trunk to the lower extremities. The first sign of measles is a prodrome that can include fever (up to 105 F) and malaise associated with the “3 C’s of measles” – cough, coryza, or conjunctivitis. Koplik spots (tiny white spots inside the mouth) are pathognomonic for measles, which are followed by a maculopapular rash.
The incubation period is ~11-13 days from exposure to the appearance of first symptoms (the prodrome). After exposure a patient is considered contagious for 4 days before to 4 days after the rash appears. Koplik spots commonly appear 2-3 days after symptom onset. The rash usually occurs about 14 days (range 7-21 days) after exposure (2-4 days after symptom onset) and lasts 5-6 days. This means it can vary quite a bit, people are often contagious approximately between days 10-18 following exposure. It also means that infected people can spread measles before they start to have symptoms, which can complicate infection control efforts.
Did you get that timeline? It is a little confusing so here it is in bullets:
- Prodrome: appears 7-14 days after exposure, often on day 11-13 (common incubation period)
- Koplik spots: appear 2-3 days after symptom onset
- Measles rash: starts 3-5 days after symptom onset (usually around day 14 after exposure), can appear anywhere from 7-21 days after exposure, lasts 5-6 days
- Contagious period: 4 days before to 4 days after the rash begins
The measles virus is only pathogenic in primates.
There is no specific treatment for measles beyond supportive care, so I am not going into that topic here. However if you read more about this, vitamin A and ribavirin have been studied.
1. Vaccination is the best way to prevent measles
This is an obvious one, but necessary to state right out the gate. The first measles vaccine came out in 1963, over 60 years ago. People born before 1957 are considered immune to measles, because the vaccine was given to such a large percentage of that population. The MMR vaccine we all know so well today was introduced in 1971.
By 2000 measles was declared eradicated in the United States, however outbreaks still occur as infections have been imported from other countries. The COVID-19 pandemic is credited for disrupting routine measles immunization services in many countries, which is likely contributing to a recent resurgence in cases globally.
Today measles vaccination is usually provided with the measles, mumps, and rubella (MMR) vaccine. There is also a measles, mumps, rubella, and varicella (MMRV) vaccine that can be used for children aged 12 months to 12 years.
MMR is recommended to be given in 2 doses. The first between age 12-15 months and the second between age 4 to 6 years (before entering school). The second dose is important, because almost everyone who does not respond to the measles component of MMR will respond to the second dose. The second dose is not to boost the first, it is to ensure to ensure an immune response is elicited. CDC recommends vaccinating specific groups of people (e.g., healthcare personnel) who do not have evidence of immunity.
Full measles vaccine recommendations are available here. Contraindications and precautions to the vaccine can be found here.
2. There is a post-exposure prophylaxis option for measles
This was something I just learned.
Not everyone who is exposed to a person with measles needs post-exposure prophylaxis (PEP), but some people may benefit from it (i.e., those without adequate presumptive evidence of immunity).
The MMR vaccine administered within 72 hours of exposure can be used as PEP. When PEP is indicated this would be the most common choice. MMR vaccination has been up to 90% effective as PEP.
Intramuscular immunoglobulin administered within 6 days of exposure can also be used as PEP. MMR vaccine and immunoglobulin should not be administered simultaneously, as the immunoglobulin can prevent the immune response to the vaccine. For patients who are immunocompromised and cannot mount an adequate immune response to the vaccine, PEP with the immunoglobulin can be considered. Immunoglobulin has been up to 95% effective as PEP.
3. Measles can be transmitted through the air
Measles can be transmitted through direct contact with infected droplets or through airborne spread when an infected person expels infectious particles into the air. Measles can remain infectious in the air for up to 2 hours after an infected person leaves an area. If a patient is in the acute care setting with measles, they need to be on standard and airborne precautions. This means surgical masks alone are not going to cut it for those who care for measles patients. N95 and negative pressure rooms should be utilized.
Persons suspected of having measles or caring for such people should exercise caution to not expose others. CDC recommends people immediately seek care by contacting their healthcare provider if they think themselves or their child has become exposed to measles.
Measles is a mandatory and immediately notifiable disease. Communication with public health authorities and use of precautionary measures to prevent spread is very important.
4. Patient education is key, knowing some simple statistics can help
Pharmacists who get questions about measles may benefit from knowing some basic information for patients to help put the dangers of measles into context. People at high risk for measles include those who are immunocompromised, infants/children below 5 years of age, people more than 20 years of age, and pregnant women.
Some notable statistics include:
- 1 in 5 unvaccinated people in the U.S. who get measles is hospitalized
- 1 in 1,000 measles cases results in acute encephalitis, which often results in permanent brain damage
- 1-3 in 1,000 children who are infected with measles will die
- Measles vaccination averted more than 60 million deaths globally from 2000-2023
The CDC and others provide a variety of excellent resources about measles for patients.
5. There are many helpful resources available to learn more about measles
My favorite resource for information on measles is CDC, which is where much of the content in this article was sourced from. The CDC has a variety of web pages dedicated to measles. Local health departments may also have some helpful information.
Here are links to several resources to learn more about measles:
- CDC: Main Measles page
- CDC: Measles clinical diagnosis and facts sheet
- CDC: Measles cases and outbreaks
- CDC: Measles resources
- CDC: Expanding Measles Outbreak in the United States and Guidance for the Upcoming Travel Season. 7 March 2025.
- MMR Vaccine VIS
- WHO: Main Measles page
- What’s going on with measles? Epidemiology. 2024.
- Measles. NEJM. 2019.
Bonus interesting fact about measles
The duration of protective immunity following wild-type measles virus infection is lifelong.
Closing comments
There is a lot to know about measles that was not covered here but information is available through the CDC and other resources linked on this web page. Given that vaccination is an effective way to prevent the spread of measles and the harm measles can cause to vulnerable population is substantial, I pray this is something of an academic exercise here and it will not become more relevant to clinical practice.
Disclaimer
The views and opinions in this article represent those of the author and may not reflect the policy or position of any previous, current, or potential future employer.
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