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April 19,
2006
Joint Statement from the American College Health
Association and Centers for Disease Control and Prevention (CDC)
Multi-State Mumps Outbreak Alert
BACKGROUND:
The state of Iowa has been
experiencing a large outbreak of mumps that began in December 2005 (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5513a3.htm).
As of April 12, 2006, 605 suspect, probable and confirmed cases have been
reported to the Iowa Department of Public Health (IDPH). The majority of
cases are occurring among persons 18-25 years of age, many of who are
vaccinated and are on college campuses.
The first reported cases in Iowa
were among college students and mumps cases have been identified in college
students in at least one other state.
Cases of mumps are under investigation in 8 neighboring states,
including Illinois, Indiana, Kansas, Michigan, Minnesota, Missouri,
Nebraska, and Wisconsin (http://www.phppo.cdc.gov/HAN/ArchiveSys/ViewMsgV.asp?AlertNum=00243).
Although the source of the current U.S. outbreak is
unknown, the mumps viral strain has been identified as genotype G, a common
genotype circulating in the United Kingdom (UK) and globally. A large
outbreak is ongoing in the UK primarily affecting unvaccinated young adults (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5507a1.htm).
Mumps Disease
Mumps is an acute viral infection characterized by a
non-specific prodrome including myalgia, anorexia, malaise, headache, and
fever, followed by acute onset of unilateral or bilateral tender swelling of
parotid or other salivary glands. In unvaccinated populations, an estimated
30%-70% of mumps infections are associated with typical acute parotitis.
However, as many as 20% of infections are asymptomatic and nearly 50% are
associated with non-specific or primarily respiratory symptoms, with or
without parotitis. Complications of mumps infection can include deafness,
orchitis, oophoritis, or mastitis (inflammation of the testicles, ovaries,
or breasts respectively), pancreatitis, meningitis/encephalitis, and
spontaneous abortion. With the exception of deafness, these complications
are more common among adults than children.
Transmission of mumps virus occurs by direct contact
with respiratory droplets, saliva or contact with contaminated fomites. The
incubation period is generally 16-18 days (range 12-25 days) from exposure
to onset of symptoms. Mumps virus has been isolated from saliva from between
2 and 7 days before symptom onset until 9 days after onset of symptoms.
Post-high school educational institutions such as colleges and universities
are at increased risk for mumps transmission because these communities are
highly mobile yet tend to concentrate large numbers of persons in living,
learning, and social environments. In addition, interactions of students
during sporting or other inter-collegiate events and mass mobilization of
students during holidays (e.g., spring break in March and April) are
opportunities for transmission among college students from geographically
diverse parts of the country and world.
RECOMMENDATIONS:
Mumps Prevention
Because undergraduate and
graduate students, faculty, and health care and other workers in colleges
and other post-high school educational
institutions may be at increased risk of acquiring mumps, they should
receive two doses of MMR vaccine or provide other evidence of mumps immunity
(physician diagnosis or laboratory evidence) (http://www.cdc.gov/mmwr/preview/mmwrhtml/00053391.htm).
The effectiveness of MMR against mumps is approximately 80% after one
dose and approximately 90% after two doses (http://www.phppo.cdc.gov/HAN/ArchiveSys/ViewMsgV.asp?AlertNum=00243).
Because the vaccine is not 100% effective, some cases can occur in
vaccinated persons.
Mumps Control
The main strategy for controlling a mumps outbreak is to define the at-risk
population and transmission setting, to prevent further transmission of
cases through isolation, and to protect susceptible populations with
vaccination
(http://www.cdc.gov/mmwr/preview/mmwrhtml/00053391.htm).
Specific recommendations
for
colleges and other
post-high school educational institutions are to:
1.
Rapidly identify susceptible persons and vaccinate with up to two doses of
MMR. Susceptible persons may include
undergraduate and graduate students, faculty, and health care and other
workers in colleges and other post-high school
educational institutions without evidence of mumps immunity (physician
diagnosis or laboratory evidence). Although birth before 1957 is
usually considered proof of immunity, during an outbreak, one dose of
vaccine can be considered for this age group if the epidemiology of the
outbreak suggests that they are at increased risk of disease.
Once vaccinated, persons, including health care workers, can be readmitted
to school or work.
2.
Exclude susceptible persons from school or work to prevent exposure and
transmission if a contraindication to MMR vaccine exists. Exclusion of those
that remain susceptible should be from the 12th day after the
first exposure through the 26th day after the last exposure
(onset of parotitis) in the affected institution.
3.
Identify and test suspected cases for mumps and report
cases
to the local public health agency. Information on collection and testing of
clinical specimens for mumps is available at
http://www.cdc.gov/nip/diseases/mumps/default.htm#lab.
4.
Isolation of persons having mumps for 9 days after symptom onset is very
important to prevent transmission on a college campus. Efforts should be
made to assure ill persons stay confined to their residence hall room and/or
home. In health care settings, the use of respiratory precautions is
recommended.
Additional information on mumps prevention and control can be found at
http://www.cdc.gov/nip/diseases/mumps/default.htm.
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