According to a recent morbidity and mortality report from the Centers for Disease Control and Prevention (CDC), “As of April 26, 2019, the CDC had reported 704 cases of measles in the United States since the beginning of 2019, representing the largest number of cases reported in the country in a single year since 1994, when 963 cases occurred, and since measles was declared eliminated in 2000”.
Indeed, new outbreaks of measles are cropping up everywhere, and we are now facing a 25-year record high for this preventable viral disease. Many states have reported measles outbreak including Arizona. Colorado. Connecticut, Georgia, Illinois, Michigan, Missouri, New Hampshire, New jersey, New York, Texas, and Washington. Why should we be concerned?
Measles has a long history in the annals of medicine. The first written account of measles appeared in the 9th century by a Persian physician. In 1757, a Scottish physician by the name of Francis Home discovered that measles is caused by an infectious agent and in 1846 Dr. Peter Panum described its incubation period and lifelong immunity after recovery from the disease. In 1912, measles became a nationally notifiable disease in the United States. The incubation period is 8-12 days with a prodromal phase of 2-4 days. The prodromal phase refers to the early stage of the disease that precede the characteristic manifestations of the fully developed illness. This prodromal phase for measles includes a stepwise increase in fever and the 3 c’s of medicine: cough, a catarrhal inflammation of the mucous membranes, and conjunctivitis (red, watery eyes). A characteristic skin rash shows up as flat, red areas covered by small confluent bumps beginning on the face and neck. The rash then begins to appear more solid and spreads to the trunk and arms. The rash starts 2-4 days after the prodrome and lasts for 5-6 days. Two to three days before the measles rash itself, infected individuals may develop clustered white lesions on the buccal mucosa opposite the lower 1st & 2nd molars. These lesions are known as Koplik’s spots and are diagnostic for measles.
Complications from measles cases are found most commonly among children less than 5 years of age and adults over 20 years of age. One in four people with measles requires hospitalization. Common complications include acute otitis media, diarrhea and vomiting resulting in dehydration. Infection of the upper airways may obstruct breathing (croup). Pneumonia (viral or superimposed bacterial) is seen in 1/20 of cases of measles and is the most common cause of death. Measles can lead to the development of bronchitis obliterans. Myocarditis is rare. Other complications include post-infectious encephalitis with an onset during the manifestation of skin rash and fever. This complication leads to death in 15% of those infected and has long term sequela in 20-40% of cases (e.g., intellectual disability, deafness). Some patients may develop a rare but brutal progressive neurologic disorder known as subacute sclerosing panencephalitis (SSPE). The first symptoms of SSPE are usually poor school performance, forgetfulness, temper outbursts, distractibility, sleeplessness, and hallucinations. The cognitive and behavioral change then progress to motor dysfunction. Seizures may occur along with uncontrollable muscle movements. Intellect and speech gradually deteriorate. SSPE can be seen 7 to 10 years after a person had apparently recovered from measles. There is an increased risk for SSPE in persons who get measles before they are 2 years of age. There is no good way to treat this complication, which is most often fatal. Another rare but often fatal complication of measles involves hemorrhages, seizures, delirium and respiratory distress. The dark eruption noted in this illness is caused by bleeding into the skin and mucous membranes. Some people call this condition “black measles”, a name also applied to the late stages of Rocky Mountain Spotted Fever.
To confirm a case of measles a physician may collect blood and/or perform a throat and/or nose swab within 3-5 days after rash onset. Management is supportive. Vitamin A helps with immune system modulation and reduces the risk of death. The World Health Organization (WHO) recommends administration of an oral dose of 200,000 IU of vitamin A per day for 2 days to children with measles in areas where vitamin A deficiency may be present. Post exposure prophylaxis is provided to those who are immunocompromised or those who have not received the vaccination. It is well worth noting that the measles, mumps and rubella (MMR) vaccine has a live attenuated virus, and it cannot be given to immunodeficient individuals. Immunoglobulis are not used to control a measles outbreak but can be administered to those at risk for severe illness and within 6 days of exposure.
Why do we vaccinate? In the prevaccination era, 90% of children acquired measles before the age of 15. It was considered a universal disease of childhood. In the US alone, 500,000 people with measles were reported each year of which 500 died, 48,000 were hospitalized, and 1,000 had permanent neurologic impairments from encephalitis. After receiving the one dose vaccine (1960s to 1979s) there were only 22,000-75,000 cases per year, with the greatest decrease in children less than 10 years of age. From 1984 to 88 there were less than 4,000 cases reported each year. Cases still occurred in patients who had already received the vaccine thus leading in 1989 to the recommendation of providing 2 doses. In 1993 the Vaccine for Children programs (a federally mandate program that provided free vaccine to children/adolescents less than 19 years of age) was initiated. In the year 2000 measles was considered eliminated from the US. Indeed, one dose of the vaccine is effective in preventing measles in 93% of cases. After 2 doses, it is effective in 97%. The duration of effectiveness is 20 years or more for measles and rubella but appears to gradually decline for mumps.