Red Book Online Outbreaks: Measles

Overview
In the United States, measles has not been circulating widely for decades because of vaccination. However, outbreaks of measles cases have been increasing since 2010, as it is easily imported by unvaccinated travelers and can spread in under-immunized communities. In 2019, more than 1200 cases of measles were reported in the United States, the highest number in decades. In 2022, 121 cases of measles were reported in the United States. As of April 28, 2023, 10 measles cases have been reported by 8 jurisdictions.
US: Measles Cases and Outbreaks | CDC   |  GLOBAL: Global Measles Outbreaks (cdc.gov)

Measles Cases in Ohio and Kentucky
As of February 5, 2023, officials at Columbus Public Health declared that the measles outbreak in central Ohio is over. The outbreak sickened 85 children. None of the children died, but 36 were hospitalized. The Measles Public Report on the central Ohio outbreak provides additional information. 

On February 24, 2023, the Kentucky Department for Public Health (KDPH) identified a confirmed case of measles in an unvaccinated individual with a history of recent international travel. While infectious, the individual attended a large religious gathering on February 17–18, 2023, at Asbury University in Wilmore, Kentucky. An estimated 20,000 people attended the gathering from Kentucky, other U.S. states, and other countries during February 17–18, and an undetermined number of these people may have been exposed. More information is available from the CDC at https://emergency.cdc.gov/han/2023/han00488.asp.

Clinical Guidance

• Presentation: Consider measles in patients with fever and rash (photo) and ask about recent international travel, exposure to international travelers, or exposure to people with measles. Patients may have non-specific symptoms (fever, cough, coryza, conjunctivitis) without rash in the prodromal phase of infection, so heightened suspicion, particularly during local outbreaks or in patients with recent travel, can be key to timely diagnosis. The incubation period between exposure and initial symptoms is approximately 8-12 days.
• Diagnosis:  Measles virus infection can be confirmed by: (1) detection of measles viral RNA by reverse transcriptase-polymerase chain reaction (RT-PCR); (2) detection of measles virus-specific immunoglobulin (Ig) M; (3) a fourfold increase in measles IgG antibody concentration in paired acute and convalescent serum specimens (collected at least 10 days apart); or (4) isolation of measles virus in cell culture.
• Who is at highest risk of acquiring measles infection:
• Unvaccinated children or adults
• Incompletely vaccinated (<2 doses of MMR) children or adults
• Individuals with known exposure to measles or recent travel to areas with active measles transmission.
• Who is at highest risk of severe measles infection or complications of measles:
• Infants and children aged less than 5 years
• adults aged more than 20 years;
• pregnant women;
• people with compromised immune systems, such as from cancer, chemotherapy, or HIV infection
• Complications: Measles can cause serious illness, even in previously healthy children. Complications of measles can include:
• Ear infections
• Diarrhea
• Pneumonia (either from measles virus itself or from bacterial superinfection)
• Encephalitis
• Death
• In addition, measles infection increases the risk of other severe infections for months or years after measles through the mechanism of immune amnesia.
• Precautions for patients with suspected or confirmed measles infection: Airborne precautions are needed whenever there is any suspicion of measles exposure. Promptly isolate, collect specimens, and report patients with suspected measles to public health.
• Prevention of measles: Vaccination is the cornerstone of measles prevention. All children should receive measles vaccination as part of the routine childhood vaccine schedule. Unimmunized or incompletely immunized children should begin catch-up vaccination as soon as possible. During an outbreak, MMR vaccine should be offered to all people with known exposure or in the outbreak community who lack evidence of measles immunity. During a community-wide outbreak that affects infants, MMR vaccine has been shown to be effective in preventing symptoms after exposure and may be recommended for infants 6 through 11 months of age. Children who receive their first MMR vaccine prior to 12 months of age will require two additional doses after 12 months of age for full protection. IGIM administered exposed, measles-susceptible people (not previously vaccinated or immunocompromised) will prevent or attenuate infection if administered within 6 days of exposure.
• Treatment: There is no specific antiviral agent for treatment of measles infection. Treatment of children with measles with oral vitamin A decreases measles-related morbidity and mortality. Dosing of vitamin A for treatment of children with measles can be found in the Red Book chapter on Measles.
• Reporting: Involvement of state and local health departments is often advisable for any suspected diagnosis of measles, as there may be specific ways these departments wish to receive specimens and manage patients.
• For more information see the Red Book chapter on Measles.

Watch this CDC video to learn more about the signs and symptoms of measles to quickly diagnose infected patients. Measles Clinical Features and Diagnosis - YouTube

Resources

• Red Book chapters: International Travel | Immune Globulin Intramuscular (IGIM)
• CDC: Measles (Rubeola)