Epi Report
Outbreaks and resurgences
Measles Updates for Clinicians
Epidemiologists Haley Gleeson, MPH; David Jung, MPH; and Kyoo Shim, MPH
of measles cases in recent
years continue to make
headlines, despite the
declaration of measles
elimination in the United
States in 2000.1 As of this writing, 142
measles cases have been confirmed in
25 states during 2018. In the DFW area
in 2018, the news of three unrelated
measles patients who had exposed people
while contagious prompted a great
deal of contact tracing for local health
departments. Although no secondary
measles infections ultimately occurred from
these cases, area clinicians were alerted to
have heightened awareness for additional
patients with measles.
10 Dallas Medical Journal December 2018
Chief Epidemiologist Wendy Chung, MD
Dallas County Health Department
The World Health Organization estimates
that the measles vaccine prevented more than
20 million deaths globally between 2000 and
2016. However, despite the availability of a
highly effective vaccine, measles continues
to be common in many parts of the world,
including parts of Europe, Asia, the Pacific,
and Africa.2,3 The increased US cases in
recent years are largely a result of continued
introduction of measles into the country
through international travelers and domestic
transmission within communities with
susceptible groups of unvaccinated persons.
The vast majority of measles cases (97%)
reported in the United States are considered
import-associated (i.e., cases that are
internationally imported or epidemiologically
linked to an imported case).4
The rising prevalence of nonmedical
vaccination declinations continues to
pose challenges to achieving community
immunity to measles. In 2017, an outbreak
of more than 70 measles cases in Somali-
American communities in Minnesota was
linked to low MMR vaccination coverage
due to concerns within the community
of a link between vaccines and autism.5
In addition to the maintenance of high
vaccination coverage, also critical in
limiting measles transmission across the
country is the rapid identification of
possible measles cases, continuous disease
surveillance and effective public health
response.
Clinical presentation of measles
Measles is a highly contagious viral illness that is transmitted person to person primarily by respiratory droplets; however, airborne transmission
also has been documented via aerosolized droplets.6 In enclosed areas, aerosolized droplets can remain suspended in the air up to 2 hours after
an infected individual leaves the space. Up to 90% of unvaccinated susceptible individuals are expected to become infected after contact with
infectious droplets. Illness begins after a 10- to 12-day incubation period and initially presents with a febrile prodrome followed by an onset of
rash within a few days. The prodrome usually lasts 2 to 4 days, with a high-grade fever and cough, coryza or conjunctivitis. Measles is associated
with a maculopapular rash lasting 5 to 6 days that generally begins at the hairline, spreads to the face and upper neck, and proceeds downward
and outward toward the extremities (Figure 1a). The period of communicability is 4 days before to 4 days after rash onset. Koplik spots can
appear as a blueish-white spotted rash on a bright red background on the buccal mucosa and are considered pathognomonic for measles (Figure
1b). Patients who meet the CDC clinical case definition for measles should be considered for immediate testing and reporting. The clinical case
definition includes a generalized rash lasting > 3 days, fever > 101oF, and cough, coryza or conjunctivitis.7
a) Generalized
rash associated
with measles
(phil.cdc.
gov/details.
aspx?pid=3186)
b) Koplik spots
(phil.cdc.
gov/details.
aspx?pid=3187)
Epidemiology of measles
Figure 1