Hazard Recognition

Measles is readily transmissible to anyone who does not have immunity through effective vaccination or from having had measles already. Workers who may be near infected individuals, including members of the public or infected coworkers, are at risk of exposure regardless of their jobs. The measles virus spreads primarily through infectious droplets or airborne particles when an infected person breathes, coughs, or sneezes and through contact with respiratory secretions or saliva from an infected person. Measles can remain in the air for up to about two hours after a person with the disease has occupied an area. Environmental surfaces, such as tables or desks, also may be contaminated with infectious respiratory secretions or saliva that can spread the virus for up to about two hours.

Susceptible (i.e., non-immune) healthcare workers (HCWs) are among those at the highest risk for contracting measles.^1,2 Because measles frequently affects children, workers in childcare facilities and schools are also at an increased risk for exposure to measles. Occupational exposure risk may be highest when measles outbreaks are occurring-especially outbreaks affecting the community in which employees work. Occupational exposure risk is much lower, but not necessarily eliminated, when there is no ongoing measles transmission.

Risks to Healthcare Workers

HCWs, including clinical and support staff, have daily encounters with sick patients and are at an increased risk for exposure to measles. Workers providing direct, face-to-face patient care may be at the highest risk of exposure, especially in communities with ongoing measles outbreaks. However, as most measles cases in the U.S. result from international travel, domestic measles outbreaks are not the only scenario in which HCWs may encounter individuals with measles; travelers may return from abroad with the measles virus and seek care at U.S. hospitals, clinics, and other facilities. Other workers in healthcare environments, such as receptionists and food services assistants, may also share breathing air with infectious patients or encounter environments with potentially infectious measles virus.

Activities that can lead to HCW exposure include:

• Triaging or providing care to an infected patient-pediatric (i.e., child) or adult.
• Performing aerosol-generating procedures (AGPs) on an infected patient (e.g. intubation, airway suctioning). Although measles is already considered an airborne-transmissible disease, AGPs may increase transmission risk by adding to the concentration of measles virus suspended in the air in the work environment.
• Working in environments where an infected patient or co-worker is or has been within the previous two hours.
• Cleaning or otherwise having contact with environmental surfaces contaminated with an infected person’s infectious body fluids (i.e., respiratory secretions, saliva).

Risks to Childcare and School Workers

Childcare Workers

In childcare facilities and schools, workers may be exposed to unvaccinated children with measles. Like anyone with measles, children can spread the virus to others through breathing, coughing, and sneezing, as well as through infectious body fluids (e.g., respiratory secretions, saliva).

There is very little data available about measles infection among childcare workers, especially because vaccine coverage in the United States is high. In 2010, 91.5% of children aged 19-35 months had received one dose of measles, mumps, and rubella (MMR) vaccine; during 2009-2010, 94.8% of kindergartners had received two vaccine doses; and in 2010, 90.5% of adolescents had received two vaccine doses.³ Pockets of unvaccinated individuals affect these vaccination statistics.

Activities that can lead to childcare worker exposure include:

• Being near a child with measles, especially when the infected child is coughing or sneezing.
• Working in an environment where an infected child or co-worker is or has been within the previous two hours.
• Wiping a child’s nose or mouth.
• Handling toys or utensils.
• Feeding a child.
• Providing first aid.
• Cleaning or otherwise having contact with environmental surfaces contaminated with an infected person’s infectious body fluids (i.e., respiratory secretions, saliva).

School Workers

There is also very little data about measles infection among teachers and other school employees. Some studies have found no evidence that teachers are at increased risk of measles as long as measles incidence (i.e., the number of cases) is low.⁴ However, teachers and other school workers may be exposed whenever they are around infected children or co-workers, and infection is much more likely among such workers who do not have immunity to the virus from vaccination or previously having had the disease.

Activities that can lead to school worker exposure include:

• Being near a child or coworker with measles, especially when the infected person is coughing or sneezing, or in an environment where the person has been within the previous two hours.
• Providing first aid.
• Cleaning surfaces contaminated with an infected person’s infectious body fluids (i.e., respiratory secretions, saliva).

Risks to Laboratory Workers

Workers in clinical and research laboratories may be exposed to infectious materials containing the measles virus. Clinical laboratory workers’ exposure risks are increased during outbreaks when they are most likely to encounter throat swabs and blood samples from infectious patients. Research laboratory workers are most at risk of occupational exposure whenever their work involves materials containing the virus. These hazards are amplified when work tasks involving measles virus generate aerosols and/or are performed outside of biosafety cabinets (practices that should be avoided; see the Laboratory Workers guidance on the Control and Prevention page).

Risks to Environmental Services Workers

Environmental services workers may have exposure to contaminated environments and surfaces that can transmit the measles virus.

Activities that can lead to environmental services worker exposure include:

• Working in environments where an infected person is or has been within the previous two hours.
• Cleaning or otherwise having contact with environmental surfaces contaminated with an infected person’s infectious body fluids (i.e., respiratory secretions, saliva). Cleaning tasks that involve using pressurized sprays of water or cleaning chemicals can create potentially infectious aerosols.

Risks to Workers Who Are Pregnant or May Become Pregnant

Measles can be especially hazardous for workers who are or may become pregnant. Pregnant women who get measles may experience more frequent or severe complications from the virus, including pneumonia and death, compared to non-pregnant women. Measles infection during pregnancy also may cause expectant mothers to have miscarriages, give birth prematurely, or deliver low-birth-weight babies.⁵

A pregnant woman who gets measles can transmit the infection to her fetus if she has the virus within about 10 days of delivery.⁶ In addition to premature birth and low birth weight, measles can lead to other complications and death among infants born with the virus or infected shortly after birth. Measles may be especially severe among such infants.

Infected partners and other contacts of susceptible, pregnant women can also easily spread measles to them.

Because of the risk of adverse health effects associated with measles infection during pregnancy, the Centers for Disease Control and Prevention (CDC) recommends that anyone without immunity get the MMR vaccine at least one month before becoming pregnant. The MMR vaccine may cause complications if administered during pregnancy.

Risks to Workers who Travel Abroad

According to the CDC, anyone who travels outside the United States is at increased risk of exposure to measles. Measles is endemic (i.e., routinely spreading) or associated with epidemics (i.e., spreading currently, but not always circulating) in many countries throughout the world.⁷ Measles is a common disease in many areas of Europe, Asia, the Pacific, and Africa.⁸

American workers who travel to countries with endemic or epidemic measles may be exposed to the virus. Not only are international travelers at risk of getting measles abroad, but they may also bring the disease back to the United States if they return before they develop measles or during the infectious period. Most U.S. measles cases result from international travel.