Measles (Rubeola)

Measles on a child's back by Watney Collection/Phototake

Measles is a highly contagious viral disease that can be fatal. In most people, the disease produces fever (temperature > 101 F [38.3 C]), a generalized rash that lasts greater than 3 days, cough, runny nose (coryza), and red eyes (conjunctivitis). The complications of measles that result in most deaths include pneumonia and inflammation of the brain (encephalitis).

Rubeola is the scientific name used for measles. People often confuse rubeola with rubella (German measles).

Rubella is the scientific name used of German measles, a different viral illness. While German measles is rarely fatal, it is dangerous in that infection of pregnant women causes birth defects and can cause miscarriage and fetal death.

Other terms describe measles. These include (erroneously) rubella, hard measles, red measles, 7-day measles, 8-day measles, 9-day measles, 10-day measles, and morbilli.

People have described cases of measles as early as the seventh century. However, it was not until 1963 that researchers first developed a vaccine to prevent measles. Before the vaccine was available, the measles virus infected almost every child because it spreads so easily. Before routine vaccination, there were approximately 3-4 million cases of measles and 500 deaths due to measles each year in the United States.

There were initially two types of vaccines developed against measles. Researchers developed one from a killed virus, and they developed the other using a live measles virus that was weakened (attenuated) and could no longer cause the disease. Unfortunately, the killed measles virus (KMV) vaccine was not effective in preventing people from getting the disease, and medical professionals discontinued its use in 1967. The live virus vaccine has been modified a number of times to make it safer (further attenuated) and today is extremely effective in preventing the disease. The currently used vaccine is a live attenuated vaccine.

The measles virus (rubeola virus, a paramyxovirus, genus Morbillivirus) causes measles.

Measles spreads through droplet transmission from the nose, throat, and mouth of someone infected with the virus. These droplets spray out when the infected person coughs or sneezes. Among unimmunized people exposed to the virus, over 90% will contract the disease.

Those people at high risk for measles include

• children less than 1 year of age (although they have some immunity passed from their mother, it is not 100% effective);
• people who have not received the proper vaccination series;
• people who received immunoglobulin at the time of measles vaccination;
• people immunized from 1963 until 1967 with an older ineffective killed measles vaccine.

Measles is a highly contagious viral illness that spreads easily from person to person, especially in those without previous vaccination. The pathogen responsible for measles is the rubeola virus.

The infected person is highly contagious for 4 days before the rash appears until 4 days after the rash appears. The measles virus can remain in the air (and still be able to cause disease) for up to 2 hours after an infected person has left a room.

A typical case of measles actually starts with a

• fever,
• runny nose,
• hacking cough, and
• red eyes (conjunctivitis).

After 2 to 4 days of these symptoms, the patient may develop spots within the mouth called Koplik spots. These spots look like little grains of white or bluish-white sand surrounded by a red ring and are usually found inside the cheek toward the back of the mouth (opposite the first and second upper molars).

The skin rash (also known as an exanthem or exanthema) appears 3 to 5 days after the onset of the initial symptoms (fever, cough, runny nose, and red eyes). The rash is a flat to slightly raised (maculopapular) red rash that usually last 5 to 6 days. It begins at the hairline and then progresses to the face and upper neck. Over the next 2 to 3 days, the rash progresses downward to cover the entire body, including the hands and feet. The rash has mostly distinct lesions, but some may overlap (become confluent). Initially, these lesions will turn white when you press on them (blanch). After 3 to 4 days, they no longer will blanch. As the rash begins to fade, there will often be a fine flaking of the skin (desquamation). The rash fades in the same order that it appears.

The fever that occurs with measles is called a stepwise fever. The patient starts with a mild fever that progressively gets higher. Fevers often reach temperatures greater than 103 F (39.4 C).

Although not as common as other symptoms, some patients may have a sore throat.

The typical time from exposure to a person infected with measles to development of the initial symptoms (incubation period) is 10-12 days (the range is 7 to 21 days). The rash occurs a few days after the initial symptoms (ranges from 7 to 18 days from exposure).

Atypical measles occurs in people who received the killed measles vaccine (KMV; only used from 1963 until 1967) and who have an exposure to wild-type measles virus. The KMV unfortunately sensitizes the patient to the measles virus but does not offer any protection. The disease is characterized by fever, pleural effusions, pneumonia, and swelling of the extremities. The rash of atypical measles is different from measles in that it may have an urticarial component (hives) and usually appears first on the ankles and wrists.

The U.S. Centers for Disease Control and Prevention (CDC) recommends that people who may have received the KMV should receive revaccination with the live measles vaccine.

Modified measles appears in patients who, because they were unimmunized, received immune globulin after exposure to a patient with measles. It also appears occasionally in young infants who have limited immunity from their mothers. The immune globulin prolongs the time from exposure to onset of symptoms (incubation period). When the symptoms do occur, they are much milder than those seen with normal measles and tend to last a shorter period of time.

The diagnosis of suspected measles is mostly clinical, meaning that the appearance and history of the patient suggest the diagnosis. In a person with known exposure to someone with measles or travel to a foreign country, health care providers should always consider measles when faced with a patient who has a high fever and characteristic rash. Until the rash appears, the presence of Koplik spots should help to suggest the diagnosis. Most cases of suspected measles in the United States turn out not to be measles (see below). It is recommended that the diagnosis be confirmed using a blood test for IgM, a type of antibody against the virus. If the IgM test is positive, medical professionals should obtain viral cultures. Contact the state and local health department immediately for any suspected case in order to follow the correct procedures for viral culture and isolation of the patient.

Any physician (including primary care physicians and pediatricians) can treat measles; however, most times there will be an infectious disease doctor consulted to be sure that the diagnosis is correct. Sometimes a general practitioner may consult a dermatologist, as well. Many physicians in current practice have never seen a case of measles, which makes it more difficult for them to diagnose it. If the patient has pneumonia or encephalitis, they may be in the intensive care unit and treated by critical care physicians.

There are many infectious diseases and other conditions that can cause some of the symptoms of measles. These include, but are not limited to, dengue fever, drug reactions, enteroviral infections, fifth disease, German measles (rubella), Kawasaki disease, Rocky Mountain spotted fever, roseola, and toxic shock syndrome. It is important that a medical expert see suspected measles cases and order appropriate laboratory tests.

Picture of Koplik spots. Source: CDC

People who have been appropriately vaccinated (or who have had the disease) and who are exposed to a patient with measles do not need to do anything. If an unimmunized person is exposed to a patient with measles, they should receive the vaccine as soon as possible. This may prevent the disease if given within 72 hours of exposure. Immune globulin may have some benefit if given within 6 days of exposure. The CDC recommends that household contacts of infected people, immunocompromised people, and pregnant women receive immune globulin. It is not recommended that health care professionals use immune globulin to control a measles outbreak.

The treatment of patients with measles focuses on symptom relief.

• Specific complications like pneumonia may require antibiotics.
• Home remedies are simply symptomatic treatment with acetaminophen (Tylenol), lots of rest, and fluids.
• Patients should be on bed rest until the fever has resolved and should remain well hydrated.
• In malnourished patients, doctors recommend vitamin A supplementation.
• Patients should be isolated to prevent spread of the disease.

Some cases of measles have an associated complication. These complications can include diarrhea, middle ear infections, pneumonia, blindness, acute brain inflammation (encephalitis, which is very rare), and persistent brain inflammation (subacute sclerosing panencephalitis or SSPE, which is extremely rare).

Blindness associated with measles is due to a combination of poor nutrition (specifically vitamin A deficiency) and the measles infection. Prevention is the most effective treatment. In third-world countries, post-measles blindness is the leading cause of blindness.

Acute encephalitis, although rare, is extremely dangerous and results in death in a significant percentage of patients who develop it. When it occurs, acute encephalitis generally starts 6 days after onset of the rash. Symptoms can include fever, headache, vomiting, stiff neck, drowsiness, seizures, and coma.

Subacute sclerosing panencephalitis (SSPE) is an extremely rare degenerative condition of the brain and spinal cord (central nervous system). A chronic infection of the central nervous system with the measles virus causes SSPE. Typically, symptoms start years after the patient had measles (average seven years, range 1 month to 27 years). The patient has a slow and progressive loss of brain function, seizures, and eventually death results. There is no known treatment for SSPE.

Most deaths from measles are due to pneumonia in children and encephalitis in adults. The people most likely to have complications (including death) are those who are malnourished or who have weakened immune systems (for example, people with AIDS or other conditions that weaken the immune system).

While measles can be fatal, it has rarely been fatal for the last 20 years in the United States. However, in 2016, 89,000 children died worldwide due to measles. About one in 500 to one in 1,000 people who contract measles will die. The low rate of death in the U.S. is because most people received immunizations, which resulted in very infrequent outbreaks. However, with increasing numbers of people who refuse vaccination in the U.S., there are likely going to be more complications and deaths from measles in the future. The people most likely to have complications (including death) are those who are malnourished or who have weakened immune systems.

If a woman contracts measles while she is pregnant, she may have a miscarriage, a stillbirth, or a preterm delivery. The infant can also be born with measles infection. There appears to be no risk of having birth defects (unlike an infection with the rubella virus, known as German measles).

Most people who contract measles will recover completely. Very few people who get measles will die. People who are malnourished or immunocompromised are more likely to have complications or die. However, it is possible for any person to die from the measles, which highlights the importance of vaccination. Almost no one who has been vaccinated has died from the disease.

The only way to prevent measles is by receiving measles immunization: This is commonly given as a two-shot series that contains measles, mumps, and rubella vaccine (MMR) or a shot containing measles, mumps, rubella, and varicella (chickenpox) vaccine (MMRV). Health care professionals do not recommend the MMRV for anyone older than 12 years of age. The current recommendation is that everyone receive two doses of the vaccine after 1 year of age. If a person receives the vaccine before 1 year of age, the person should receive two additional doses.

The measles-containing vaccines (MMR and MMRV) are not 100% effective, and this is why it is critical that everyone receives an immunization. When people skip vaccinations, they put others at risk. This is why most states have laws requiring vaccination. Unfortunately, many states allow people to refuse vaccination based on varying criteria. Due to a sharp increase in the number of cases of measles in 2014 and 2015, there has been a renewed urgency to require immunization for everyone.

No vaccine is 100% effective. In 2012, the Cochrane Collaboration estimated that one dose of MMR would protect prevent 92% of secondary measles cases (a case caused by exposure to another person with the disease), and two doses would be 95% effective. However, if most of the population is immunized (known as herd immunity), the effectiveness of the vaccine is markedly increased. When under-vaccinated groups of close-knit communities are exposed to a single individual with measles, an outbreak can develop very quickly, as occurred in 2019.

The measles vaccine is also available as a single vaccine. However, in most cases, there is no reason to utilize the measles vaccine alone without mumps and rubella vaccine. The complete schedule of recommended vaccinations is available from the CDC (http://www.cdc.gov/vaccines/schedules/index.html).

Although measles was extremely rare in the United States in the 1990s and early 2000s, recently, there has been a marked increased number of cases.

When the number of vaccinated individuals starts to decrease, the disease starts to occur more frequently. This occurred from 1989 until 1991 in the U.S. During that period, there were 55,000 cases and 123 deaths from measles in the U.S. Due to a massive public health effort, almost all children in the U.S. received the measles vaccine before entering school. The number of cases of measles in the U.S. dropped to only 37 in 2004. At that time, most cases originated outside of the U.S. These cases came from three common sources: infants being adopted from China, U.S. travelers being exposed while out of the country (now most commonly from European travel), and from foreign travelers visiting the U.S.

However, in 2011, the number of cases grew to 222 because more people avoided vaccinations. Fortunately, there were no deaths among those 222. In 2014, the number of cases jumped dramatically to 644 cases, and there were 14 separate outbreaks. The largest outbreak was due to many unvaccinated children and adults in an Amish community in Ohio. A large multistate outbreak of measles started in December 2014 at Disneyland in California and continued into 2015. There were 48 cases of measles in 13 states in the first half of 2016. Most of the recent outbreaks traced back to individuals who refused vaccination and had foreign travel prior to onset of the illness. In 2018, an outbreak in New York City resulted in 58 cases and cost the health department over $400,000.

Many states allow people to refuse vaccination for religious reasons (although no organized religion prohibits vaccination) and 17 states allow parents to refuse vaccinations for philosophical reasons. The only way to prevent this problem is to change laws so that parents can no longer refuse vaccination except for documented allergy to vaccine components. Many states have up to 40% of preschoolers without proper vaccinations.

The following groups of people should not receive measles vaccinations:

• People who have suffered a severe allergic reaction to either the measles vaccine or its components (gelatin or neomycin) should not receive the vaccine.
• Women known to be pregnant should not receive the vaccine. Avoid pregnancy for four weeks after vaccination.
• Severely immunocompromised patients (cancer patients or patients who are receiving large doses of corticosteroids) should not receive the vaccine. However, those leukemia patients who have been in remission for three months may receive the MMR.
• Patients with severe human immunodeficiency virus (HIV) infections should not receive the vaccine. However, it is safe for asymptomatic patients with HIV to receive vaccinations. The CDC has issued guidelines for vaccination based on the CD4+ T-lymphocyte counts.
• People with a moderate to severe acute illness should wait until their illness resolves before receiving the vaccine.

Patients with history of thrombocytopenic purpura or thrombocytopenia (low platelets) may be at increased risk, and immunization should be decided on a case-by-case basis.

What side effects or adverse reactions can occur with the measles vaccination?

Adverse reactions to measles vaccination (as part of the MMR) include fever, rash, joint aches, and low platelet count (thrombocytopenia). Some adult women will suffer joint pain that is due to the rubella component of the vaccine. The fever usually occurs 7 to 12 days after the vaccination, and the rash occurs 7 to 10 days after vaccination.

If a child has an egg allergy can they still receive the measles vaccine?

Although the measles vaccine is made using chick embryos, there is no evidence of increased reactions in people with an egg allergy. Therefore, the CDC recommends giving MMR vaccine to egg-allergic children without any prior skin testing or the use of special protocols.

What can I do if I have not received the vaccine and I am exposed to a person with measles?

If a person is exposed to measles, a few steps can help prevent getting the disease. This is known as post-exposure prophylaxis. If the exposure to measles has been within 3 days, the recommended course of action is immunization with the measles-mumps-rubella (MMR) or the measles-mumps-rubella-varicella (MMRV) vaccine. If it has been more than 72 hours, but less than 6 days, the person can receive immunoglobulin. These are not guaranteed to prevent measles, but it can decrease the likelihood of the illness.

Who should be revaccinated (receive a booster shot) against measles?

The following group of people should be considered unvaccinated and should receive at least one dose of vaccine:

• People vaccinated before their first birthday should be revaccinated.
• Anyone known to have been vaccinated with the killed measles vaccine (KMV) should be revaccinated.
• Anyone vaccinated with KMV who received their dose of live measles vaccine with four months of their last dose of vaccine should be revaccinated.
• Anyone vaccinated before 1968 in whom it is not known if the vaccine was KMV or not should be revaccinated.

What should I do if I am not sure if I have been properly vaccinated or my vaccine records have been lost?

If you are unsure of your vaccine status against measles (especially if you are going to work in health care), you should have a blood test to measure your titer of antibodies against measles.