Measles: Outbreak Calls for Precautionary Measures

Measles is a highly contagious viral respiratory illness characterized by a red rash, fever, cough, congestion and conjunctivitis (pink eye). Complications from the measles have serious health effects and can cause death in vulnerable populations.

The 2019 measles outbreak accounts for the highest number of cases reported in the U.S. since 1994. More than 700 cases of measles were confirmed in 22 states between January and April, according to the Centers for Disease Control and Prevention (CDC).

Vaccination prevents the measles. Consistent good hygiene practices and other controls, such as avoiding contact if immunity is not established, help reduce the spread of illness in the workplace and other communal places such as schools and daycare centers, public transport, fitness and medical facilities, theaters, stores and homes.

Exposure Risk

Most cases of measles in the U.S. are linked to unvaccinated international travelers who have arrived in the U.S. after spending time in regions where measles is a public health threat. Measles is especially common in developing nations, but it also occurs in developed countries, the World Health Organization reports. In recent years, measles importations have come from frequently visited countries including England, France, Germany, India and the Philippines.

Although measles was declared eliminated in the U.S. in 2000, it has since reoccurred. Outbreaks typically affect pockets of the unvaccinated population.

The virus is transmitted by direct or airborne contact with infectious droplets spread when an infected person breathes, coughs or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area. Measles is infectious from four days before the rash appears through four days after rash onset.

High risk: A person who is not vaccinated and who may experience severe illness if he or she becomes infected with measles is considered a high-risk contact. This also applies to someone with a high likelihood of exposure due to the intensity or duration of exposure.

People at high risk for severe illness and complications from measles include:

• Infants and children aged <5 years
• Adults aged >20 years
• Pregnant women
• Those with compromised immune systems

Immunity: People are presumed to be immune to measles if they have:

• Written documentation of adequate vaccination, either one or more doses of a measles-containing vaccine administered on or after the first birthday for preschool-age children and adults not at high risk, or two doses of measles containing vaccine for school-age children and adults at high risk, including college students, health care personnel and international travelers
• Laboratory evidence of immunity or confirmation of having had measles
• Birth before 1957

Vaccination

Measles can be prevented with vaccine, which is administered as the combination measles-mumps-rubella (MMR) vaccine, or in a combination that includes varicella (MMRV). Single-antigen measles vaccine is not available.

All 50 states and the District of Columbia require vaccinations for children entering kindergarten. All states allow medical exemptions to these requirements, and some states also offer exemptions for religious and philosophical reasons.

One dose of MMR vaccine is approximately 93 percent effective at preventing measles; two doses are approximately 97 percent effective. Almost everyone who does not respond to the measles component of the first dose of MMR vaccine at age 12 months or older responds to the second dose. After two doses, a booster vaccine is not needed later in life, according to public health officials.

What to Do in the Event of Exposure

The MMR vaccine, if administered within 72 hours of initial exposure, or immunoglobulin (IG), if administered within six days of exposure, may help prevent measles or lessen symptoms if measles develops. These interventions are called post-exposure prophylaxis (PEP).

Public health authorities recommend the following measures. (Refer to “Public health responses during measles outbreak in elimination settings: Strategies and Challenges,” Human Vaccines and Immunotherapeutics, 14(9), 2018):

• Offering vaccination to non-immune individuals
• Providing PEP to susceptible contacts
• Practicing social distancing (isolation, quarantine, exclusion)
• Encouraging monitoring and reporting of symptoms

U.S. public health recommendations include the following:

1. People without evidence of immunity and/or who have been exempted from measles vaccination for medical, religious or other reasons, and who do not receive PEP within the appropriate time frame should be excluded from affected institutions in the outbreak area until 21 days after the onset of rash in the last case of measles.
2. If MMR vaccine is not administered within 72 hours of exposure as PEP, MMR vaccine should still be offered at any interval following exposure to the disease to provide protection from future exposures. People who receive MMR vaccine or IG as PEP should be monitored for signs and symptoms consistent with measles for at least one incubation period.
3. Infected people should be isolated for four days after they develop a rash.
4. Airborne precautions should be followed in health care settings regardless of presumptive immunity status. This includes use of respiratory protection consistent with airborne infection control precautions (use of an N95 respirator or a respirator with similar effectiveness in preventing airborne transmission). The preferred placement for patients who require airborne precautions is in a single-patient airborne infection isolation room.

Occupational Safety and Health Administration (OSHA) standards intended to help protect workers from exposure to measles include the Personal Protective Equipment standard (29 CFR 1910.132) and the Respiratory Protection standard (29 CFR 1910.134). During outbreaks, jurisdictions and organizations may consider quarantines, postponing group events or taking advantage of opportunities to educate the public about measles prevention. In one case in early May 2019, for example, the island of St. Lucia prevented passengers and crew members from getting off a cruise ship at its port after someone on the vessel was diagnosed with measles.

Workplace policies: Employment law attorneys advise employers to develop policies regarding notifications of potential exposure or a confirmed case of measles.

Provisions in the Health Insurance Portability and Accountability Act (HIPAA) prohibit sharing of personal, protected health information. In addition, measles may be considered a protected condition under the federal Americans with Disabilities Act (ADA) and/or state and local law counterparts to the ADA. Disclosing that a particular employee has measles may violate one of these laws.

Personal responsibility: If you suspect or know you have been exposed to measles, it’s important to immediately notify your personal health care

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