Saturday, April 20, 2024

Measles

Practice Essentials

Measles, also known as rubeola, is one of the most contagious infectious diseases, with at least a 90% secondary infection rate in susceptible domestic contacts. Despite being considered primarily a childhood illness, measles can affect people of all ages. See the image below.

Face of boy with measles.

Face of boy with measles.

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See Pediatric Vaccinations: Do You Know the Recommended Schedules?, a Critical Images slideshow, to help stay current with the latest routine and catch-up immunization schedules for 16 vaccine-preventable diseases.

Although the elimination of endemic measles transmission in the US in 2000 was sustained through at least 2011, according to a CDC study, cases continue to be caused by virus brought into the country by travelers from abroad, with spread occurring largely among unvaccinated individuals. In 88% of the cases reported between 2000 and 2011, the virus originated from a country outside the US, and 2 out of every 3 individuals who developed measles were unvaccinated. Moreover, the director of the CDC noted that, in 2013, US measles cases increased threefold from the previous median, to 175 cases.
Most of these cases were outbreaks in children whose parents had refused immunization.

This trend of increased incidence continued into 2014. From January 1 to May 23, 2014, 288 confirmed cases were reported to the CDC, a figure that exceeds the highest reported annual total number of cases (220 cases in 2011) since measles was declared eliminated in the United States in 2000. Of the 288 cases, 200 (69%) occurred in unvaccinated individuals and 58 (20%) in persons with unknown vaccination status. Nearly all of the 2014 cases reported thus far (280 [97%]) were associated with importations from at least 18 countries. Eighteen states and New York City reported measles infections during this period, and 15 outbreaks accounted for 79% of reported cases, including a large ongoing outbreak in Ohio primarily among unvaccinated Amish persons, with 138 cases reported.
 Public health officials confirmed a total of 59 cases of measles in California residents since the end of December 2014. Of the confirmed cases, 42 have been linked to an initial exposure in December at Disneyland or Disney California Adventure Park in Anaheim, California.

A study by Gastañaduy et al found that during the 2014 measles outbreak, the spread of measles was contained in an undervaccinated Amish community by the isolation of case patients, quarantine of susceptible individuals, and giving the MMR vaccine to more than 10,000 people. As a result, the spread of measles was limited to about 1% in an Amish community of 32,630.
  

981 cases, the highest number of cases since 1992, have been reported in 2019, Measles have been reported in 26 states from January 1 to May 31, 2019: Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Missouri, New Mexico, Nevada, New Hampshire, New Jersey, New York, Oklahoma, Oregon, Pennsylvania, Texas, Tennessee, and Washington.

See 11 Travel Diseases to Consider Before and After the Trip, a Critical Images slideshow, to help identify and manage several infectious travel diseases.

Guidelines on measles from the American Academy of Pediatrics

The American Academy of Pediatrics released updated measles guidelines in response to the national outbreak of the disease. The new guidelines feature changes in the evidence required for measles immunity, the use of immune globulin, vaccination for healthcare personnel, and the management of patients with HIV infections and other susceptibilities.

Any of the following constitutes evidence of immunity to measles:

See the list below:

Documentation of age-appropriate vaccination with a live measles virus–containing vaccine (one dose for preschool-aged children, two doses for children in kindergarten through 12th grade)

Laboratory evidence of immunity

Laboratory confirmation of disease

Birth before 1957

Use of immune globulin

See the list below:

Clinicians can administer immune globulin either intramuscularly or intravenously within 6 days of exposure to prevent or modify measles response in people who lack evidence of measles immunity.

The recommended dose is 0.50 mL/kg administered intramuscularly, with a maximum volume of 15 mL.

Groups who are at higher risk for complications from severe measles should receive intravenous application at a dose of 400 mg/kg.

People with HIV infections

See the list below:

Measles immunization (in the form of the measles, mumps, and rubella vaccine) for everyone older than 12 mo who is infected by HIV, except those who have evidence of severe immunosuppression. Measles can be fatal in patients with HIV.

Immune globulin prophylaxis for HIV-infected children who are exposed to measles, depending on their immune status and measles vaccine history.

Healthcare personnel

See the list below:

Immunization programs for healthcare personnel, including students, who may be in contact with patients with measles.

Birth before 1957 is not a guarantee of measles immunity; facilities should consider vaccination of unimmunized healthcare personnel who lack laboratory evidence of immunity who were born before 1957.

Management of susceptible individuals

See the list below:

Clinicians can best manage immunodeficient and immunosuppressed patients exposed to measles if they have previous knowledge of the patients’ immune status.

Children should receive measles vaccination prior to treatment with biological response modifiers, such as tumor necrosis factor antagonists.

Susceptible patients with immunodeficiencies should receive immune globulin after measles exposure.

Warning against giving live-virus measles vaccines to immunocompromised patients with disorders associated with increased severity of viral infections (except people with HIV who do not have evidence of severe immunosuppression).

Recommendation not to give immunization for at least a month after a patient has finished a high-dose course of corticosteroids, such as prednisone.

Signs and symptoms

Onset of measles ranges from 7-14 days (average, 10-12 days) after exposure to the virus. The first sign of measles is usually a high fever (often >104o F [40o C]) that typically lasts 4-7 days. The prodromal phase is also marked by malaise; anorexia; and the classic triad of conjunctivitis, cough, and coryza (the “3 Cs”). Other possible prodromal manifestations include photophobia, periorbital edema, and myalgias.

Enanthem

Koplik spots—bluish-gray specks or “grains of sand” on a red base—develop on the buccal mucosa opposite the second molars

Generally appear 1-2 days before the rash and last 3-5 days

Pathognomonic for measles, but not always present

Rash

On average, the rash develops about 14 days after exposure

Mild pruritus may also occur

Blanching, erythematous macules and papules begin on the face at the hairline, on the sides of the neck, and behind the ears

Within 48 hours, the lesions coalesce into patches and plaques that spread cephalocaudally to the trunk and extremities, including the palms and soles, while beginning to regress cephalocaudally, starting from the head and neck

Lesion density is greatest above the shoulders, where macular lesions may coalesce

The eruption may also be petechial or ecchymotic in nature

Patients appear most ill during the first or second day of the rash

The exanthem lasts for 5-7 days before fading into coppery-brown hyperpigmented patches, which then desquamate

Immunocompromised patients may not develop a rash

Clinical course

Uncomplicated measles, from late prodrome to resolution of fever and rash, lasts 7-10 days

Cough may be the final symptom to appear

Modified measles

Occurs in individuals who have received serum immunoglobulin after exposure to the measles virus

The incubation period may be as long as 21 days

Similar but milder symptoms and signs may occur

Atypical measles

Occurs in individuals who were vaccinated with the original killed-virus measles vaccine between 1963 and 1967 and who have incomplete immunity

A mild or subclinical prodrome of fever, headache, abdominal pain, and myalgias precedes a rash that begins on the hands and feet and spreads centripetally

The eruption is accentuated in the skin folds and may be macular, vesicular, petechial, or urticarial

See Clinical Presentation for more detail.

Diagnosis

Although the diagnosis of measles is usually determined from the classic clinical picture, laboratory identification and confirmation of the diagnosis are necessary for public health and outbreak control. Laboratory confirmation is achieved by means of the following:

Serologic testing for measles-specific IgM or IgG titers

Isolation of the virus

Reverse-transcriptase polymerase chain reaction (RT-PCR) evaluation

Measles-specific IgM titers

Obtain blood on the third day of the rash or on any subsequent day up to 1 month after onset

The measles serum IgM titer remains positive 30-60 days after the illness in most individuals but may become undetectable in some subjects at 4 weeks after rash onset

False-positive results can occur in patients with rheumatologic diseases, parvovirus B19 infection, or infectious mononucleosis

Measles-specific IgG titers

More than a 4-fold rise in IgG antibodies between acute and convalescent sera confirms measles

Acute specimens should be drawn on the seventh day after rash onset

Convalescent specimens should be drawn 10-14 days after that drawn for acute serum

The acute and convalescent sera should be tested simultaneously as paired sera

Viral culture

Throat swabs and nasal swabs can be sent on viral transport medium or a viral culturette swab

Urine specimens can be sent in a sterile container

Viral genotyping in a reference laboratory may determine whether an isolate is endemic or imported

In immunocompromised patients, isolation of the virus or identification of measles antigen by immunofluorescence may be the only feasible method of confirming the diagnosis

Polymerase chain reaction

RT-PCR, if available, can rapidly confirm the diagnosis of measles

Blood, throat, nasopharyngeal, or urine specimens can be used

Samples should be collected at the first contact with a suspected case of measles

Case reporting

Immediately reporting any suspected case of measles to a local or state health department is imperative. The US CDC clinical case definition for reporting purposes requires only the following:

Generalized rash lasting 3 days or longer

Temperature of 101.0°F (38.3°C) or higher

Cough, coryza, or conjunctivitis

For reporting purposes for the CDC, cases are classified as follows:

Suspected: Any febrile illness accompanied by rash

Probable: A case that meets the clinical case definition, has noncontributory or no serologic or virologic testing, and is not epidemiologically linked to a confirmed case

Confirmed: A case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed case; a laboratory-confirmed case need not meet the clinical case definition

See Workup for more detail.

Management

Treatment of measles is essentially supportive care, as follows:

Maintenance of good hydration and replacement of fluids lost through diarrhea or emesis

IV rehydration may be necessary if dehydration is severe

Vitamin A supplementation should be considered

Postexposure prophylaxis should be considered in unvaccinated contacts; timely tracing of contacts should be a priority. Patients should receive regular follow-up care with a primary care physician for surveillance of complications arising from the infection.

Vitamin A supplementation

The World Health Organization recommends vitamin A supplementation for all children diagnosed with measles, regardless of their country of residence, based on their age,
as follows:

Infants younger than 6 months: 50,000 IU/day PO for 2 doses

Age 6-11 months: 100,000 IU/day PO for 2 doses

Older than 1 year: 200,000 IU/day PO for 2 doses

Children with clinical signs of vitamin A deficiency: The first 2 doses as appropriate for age, then a third age-specific dose given 2-4 weeks later

See Treatment and Medication for more detail.

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