Clinical Features
Measles is highly contagious, infecting about 90% of susceptible people who are exposed to it [1-3], and is primarily contracted when a person comes into contact with oral or nasal secretions of a contagious individual. Communicability begins several days before, and continues several days after the rash appears, but Measles is not contagious once the rash begins to go away. Once exposure has occurred, there is a 7-14 day incubation period before the initial symptoms of fever, hacking cough, runny nose, and conjunctivitis (pink-eye) appear. The distinctive Koplik's spots will appear 2-4 days later, which will be followed by the rash by 1-2 days. [2, 3]
Measles rash is flat and red, with groups of small bumps. It begins on the face, usually in front of and below the ears, and on the side of the neck, first as discolouration, and soon mixed with groups of small, solid elevations. Within a day or two, the rash begins to spread to the trunk and then to the lower limbs. During peak severity, which is usually the first day or two of the rash, the patient's body temperature may exceed 104°F (40°C), with puffy/swollen eyes, conjunctivitis, sensitivity to light (photophobia), a hacking cough, extensive rash, exhaustion, and mild itching. Within 3-5 days, the fever will fall and the patient will feel more comfortable with their rash fading quickly. Sometimes, after the rash fades, there will be some peeling of the affected areas, which may go unnoticed in children who are bathed daily. [2, 3] Contracting the Measles naturally will usually result in life-long immunity [1-3].
Complications
Here are the approximate risks of Measles complications, as per the CDC [1]. These statistics were based on surveillance data collected between 1985-1992:
Diarrhea - 8%
Otitis media - 7%
Pneumonia - 6%
Encephalitis - 0.1%
Seizures - 0.6-0.7%
Death - 0.2%
Between 1987 and 2000 in the United States, there were 67,032 reported cases of the Measles (with age information available), and of those confirmed cases, 19,480 (29%) had at least one complication.
12, 876 (19.2%) were hospitalized,
5482 (8.2%) had diarrhea,
4879 (7.3%) had Otitis Media (ear infection),
3959 (5.9%) had pneumonia,
177 (0.3%) died, and
97 (0.1%) had encephalitis [3]
About 25% of Measles cases with encephalitis will result in some form of long-term neurologic damage, which ends up being about 0.025% of all Measles cases. [1] Postinfectious encephalomyelitis (PIE) occurs in about 0.1%-0.3% of all infected persons. As many as 25% of people with PIE as a result of Measles will die, and roughly 33% of survivors will have life-long neurological complications including severe retardation, motor impairment, blindness and sometimes hemiparesis (muscle weakness due to nerve damage). [3] This means that about 0.05% of all Measles infections will result in long-term complications.
This is the number of reported cases of the Measles, as well as the number of reported Measles deaths, per year between 1968-2010:
Who is at Increased Risk for Complications?
There are a few subsets of the population that are at greater risk for serious complications from the Measles. Children under 5 years old, adults over 20, certain immunocompromised people, individuals deficient in Vitamin A, people who are malnourished, and pregnant women are all at a higher risk for severe complications. [1, 3]
Children Under 5 are more likely to have diarrhea, ear infections, encephalitis, or pneumonia, and are more likely to require hospitalization or die as a result of the Measles than children over 5 years of age. [1, 3] Babies born to mothers who are HIV-positive become susceptible to Measles earlier than babies born to HIV-negative women. [3]
Adults over 20 have a higher chance, due most likely to the decline in cell-mediated immunity that begins in adulthood, to suffer from encephalitis, hepatitis, low calcium, or pancreatitis after the Measles. [3] Adults are also at an increased risk of pneumonia and hospitalization. [1]
People who have HIV, AIDS, congenital immunodeficiency, lymphoma, and Leukemia are at a higher risk for severe Measles complications such as encephalitis and pneumonia, are more likely to require hospitalization, and are more likely to die than immunocompetent people. [1, 3] "Suppression of lymphocyte function, resulting from congenital defects in T lymphocyte function, bone marrow transplantation, chemotherapy for cancer, or immunosuppressive doses of steroids, is associated with increased severity of measles." [3]
Some immune compromised populations, such as children with defects in macrophage function only, or patients with B cell immune deficiency syndromes without T cell abnormalities, do not appear to be at a higher risk for Measles complications. [3]
Vitamin A Deficiency leads to increased risk of complications, and increased case-fatality rates. It makes one more inclined to severe corneal inflammation (Keratitis), corneal scarring, and blindness, as well as pneumonia and diarrhea from the Measles. Malnourishment also leads to higher case-fatality rates, and Measles can actually contribute to the development of malnutrition and Vitamin A deficiency. [2, 3]
Pregnant women have an increased risk of preterm labour, miscarriage, and low birth-weight infants, as well as an increased risk of maternal death from Measles infection during pregnancy. [1, 3]
Diagnosis and Treatment
Measles can be clinically diagnosed by identification of the Koplik's Spots or the rash, and can be confirmed by laboratory diagnosis through serologic testing or viral detection using a culture or reverse transcription-PCR of throat swabs, blood, or urine samples. [1, 2]
Treatment for the Measles is mostly supportive, meaning focuses on maintaining the comfort of the patient rather than a treatment to cure the underlying illness. However, Vitamin A therapy is also recommended for all children who have the Measles, because it has been shown to reduce the morbidity and mortality associated with the infection. [2, 3] An oral dose is recommended once per day for two days, dependent upon the child's age:
< 6 months of age - 50,000 IU
6 months to 11 months - 100,000 IU
> 1 year of age - 200,000 IU [2]
Other Information of Interest
"An infant whose mother has had measles receives antibodies transplacentally; these antibodies are protective for most of the first 6 to 12 mo of life. Lifelong immunity is conferred by infection." [2]
"Before the introduction of measles vaccines, measles virus infected 95%–98% of children by age 18 years, and measles was considered an inevitable rite of passage. Exposure was often actively sought for children in early school years because of the greater severity of measles in adults." [3]
"Measles case-fatality rates have declined in association with economic development and associated decreased crowding, older age at infection, improved nutrition, and treatment for secondary pneumonia." [3]
"In New York State, measles mortality decreased by >15-fold long before the introduction of measles vaccination (figure 2)." [3]
"High case-fatality rates in developing countries are due to a young age at infection, crowding, underlying immune deficiency disorders, vitamin A deficiency, and lack of access to medical care." [3]
"In countries with high measles mortality, treatment with vitamin A once daily for 2 days (200,000 IU for children 12 months of age or 100,000 IU for infants ≥12 months) is associated with an ∼50% reduction in mortality. The World Health Organization recommends vitamin A therapy for all children with measles. For hospitalized children <2 years old with measles in the United States, the American Academy of Pediatrics recommends a single dose of vitamin A (200,000 IU for children ≥12 months; 100,000 IU for those <12 months." [3]
"The source of almost half of the measles importations in 2011 was the WHO European Region, which reported >30,000 cases of measles, including 27 cases of measles encephalitis, a complication that often results in permanent neurologic sequelae, and eight measles-related deaths in 2011." [9]
"Among the 70 (32%) measles patients who were hospitalized [during 2011 in the US], 17 (24%) had diarrhea, 15 (21%) were dehydrated, and 12 (17%) had pneumonia. No cases of encephalitis and no deaths were reported." [9; clarification mine]In the first 19 weeks of 2011 in the United States, there were 118 reported cases of Measles. 47 (40%) of the affected people were hospitalized, and 9 (7.6%) had pneumonia, but there were no reports of encephalitis or death. [10]
WHO European Region saw a total of 32, 480 cases of Measles in 2010. There were 21, 877 (67.4%) hospitalizations, and 21 (0.06%) deaths reported. [11]
Between 2008-2011, France saw >20,000 cases of Measles. Almost 5,000 (~25%) of the affected were hospitalized, including 1,023 (~5.1%) for severe pneumonia, and 27 (~0.1%) for encephalitis/myelitis. There were 10 (~0.05%) deaths reported. [12]
Disclaimer
This information is presented and offered irrespective to your stance on vaccines, and is intended neither to persuade anyone to change their decision, nor fuel a vaccine debate. Parents, whether they vaccinate or not, should know what this disease looks like, know the risks of it, how to care for it, and when to seek help for it. If anyone wishes to add onto the information provided here, you may feel free to do so in the comments. Please make sure your information includes citations, and is not posted with the intention of debating or attacking someone else.
The information contained within this post is not intended as diagnosis or medical advice. If you think you or your child has the Measles, please seek the advice of your health care provider.
References
[1] CDC Pink Book - Measles
[2] Merck Manual - Measles
[3] The Clinical Significance of Measles: A Review; Robert T. Perry, Neal A. Halsey 2004
[4] CDC MMWR Vol. 48, No 53 - Summary of Notifiable Diseases - United States, 1999
[5] CDC MMWR Vol. 60, No. 53 - Summary of Notifiable Diseases - United States, 2011
[6] CDC Compressed Mortality File, 1968-1978
[7] CDC Compressed Mortality File, 1979-1998
[8] CDC Compressed Mortality File, 1999-2010
[9] CDC MMWR Measles - United States, 2011
[10] Measles - United States, January-May 20, 2011. MMWR 2011 May 27;60(20):666-8.
[11] ECDC Annual Epidemiological Report - Reporting on 2010 Surveillance Data and 2011 Epidemic Intelligence Data, 2012. Pages 195-196
[12] Measles Elimination Efforts and 2008-2011 Outbreak, France. Emerg Infect Dis. 2013 March; 19(3): 357–364.
