Infectious Diseases: Measles

In 2000, the U.S. Centers for Disease Control and Prevention (CDC) declared that measles had been eliminated within the country. The number of active cases can vary from year to year for many reasons, including the vaccination status of specific communities and the level of transmission via travelers to/from foreign countries. The impact of an outbreak can be significant and, so far in 2019, news reports have detailed three instances of quarantines, one among individuals onboard a Caribbean cruise ship and the others at two different California college campuses.

What is measles and how is it transmitted?

Measles is a highly contagious acute viral respiratory illness that is transmitted by direct contact with infectious droplets that are be released into the air when an infected person breathes, coughs or sneezes. It can remain infectious in the air for as long as two hours after the infected person has left the area. As a result, measles is one of the most contagious of all infectious diseases. Infected people are considered contagious from four days before to four days after the rash appears.

How prevalent is it?

More than 700 cases of measles were reported in the first four months of 2019, and each week the CDC updates a map detailing cases in each state. Cases usually occur in clusters and originate in areas where there are people who are not vaccinated or involve travelers who bring the disease in from countries where the disease is more common, including Europe, Asia, the Pacific and Africa. In recent years, many measles importations have originated in locations that are popular vacation destinations. Unvaccinated travelers that have been infected with measles abroad can be the source of multiple infections in groups or communities of people who have not been vaccinated.

How effective is the measles vaccine?

The measles vaccine is one component of the measles-mumps-rubella (MMR) vaccine given to children aged one through 12 years old. It is not available as an individual vaccine. The CDC reports that a single dose of the MMR vaccine is about 93% effective and the two dose vaccination protocol is about 97% effective.

Who should be vaccinated?

The CDC has age-specific recommendations. Children should receive the first MMR immunization between the ages of 12-15 months and a second dose between ages four and six or at least 28 days after the first dose. Students at post-high school educational institutions who cannot provide proof of immunity should have two doses of the MMR vaccine spaced at least 28 days apart. The agency recommends that adults born during or after 1957 who do not have evidence of immunity against measles should get at least one dose of MMR vaccine. The agency also has specific recommendations for people of all ages who travel internationally.

How can I prevent transmission in my practice? What should I do if a member of my staff is exposed to measles?

Continuing to follow standard universal precautions remains the best method of reducing the chance of transmitting measles to staff and other patients. The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends that people working in healthcare settings have documented evidence of immunity against measles. The dental practices’ standard human resources/infection control protocols should include confirmation that staff records and staff immunizations are up to date. Staff exposed to measles who cannot readily show that they have evidence of immunity against measles should be offered post-exposure prophylaxis (PEP) or be excluded from the practice setting. Measles PEP may involve being given the MMR vaccine, which may provide some protection or modify the clinical course of disease if given within 72 hours of initial measles exposure, or immunoglobulin (IG), if given within six days of exposure.

How can my staff and I tell if a patient has it?

Many of the symptoms of measles become apparent within one to two weeks of infection and can include high fever, cough, runny nose, conjunctivitis, rash, and, in some cases, tiny white spots inside the mouth. The measles rash typically spreads from the head to the trunk to the lower extremities.

What should we do if a patient has it? Or if we suspect the patient has it?

The general best practices in situations when you or your staff suspects that a patient has measles, are to ask about their:

Vaccination status
Recent international travel
Travel to domestic venues frequented by international travelers
Contact with anyone who has traveled internationally
Measles in the local community

The CDC recommends that healthcare providers ask patients to confirm their vaccination status by providing written documentation. Other good rules of thumb are to isolate infected people from other patients and staff; follow the appropriate airborne precautions; and to have all healthcare staff entering the room, regardless of their presumed immunity status, use respiratory protection consistent with airborne infection control precautions, such as using an N95 respirator or a respirator with similar effectiveness in preventing airborne transmission. A final best practice is to always — and immediately — report suspected measles cases to the local health department.

Resources

From the ADA:

Hand Hygiene
From the Journal of the American Dental Association: Managing measles in dental practice: A forgotten foe makes a comeback [PDF]. July 2015 Volume 146, Issue 7, Pages 558–560.

From the CDC:

For more information, please contact the Center for Dental Practice at dentalpractice@ada.org or 312-440-2895.

The ADA’s Council on Ethics, Bylaws and Judicial Affairs has issued a comprehensive statement to guide members as they consider the many potential ethical implications of the measles crisis.