++
Mumps is a communicable systemic
viral illness usually characterized by parotitis. With the widespread
use of mumps vaccine, the disease has become less common. A significant
number of infections are asymptomatic.
++
Humans are the only known natural hosts of mumps virus. The virus
can be recovered from patients with active disease from saliva, cerebrospinal
fluid (CSF), urine, blood, breast milk, and infected tissue.1,2 Mumps
virus infections are spread by respiratory droplet or by direct
contact with infected saliva. Virus can be demonstrated in respiratory
secretions up to 7 days before through 9 days after the onset of
parotitis.2 Secondary attack rates of mumps among
susceptible household contacts have been shown to be less than that
of measles or varicella, suggesting a less efficient transmission
of the mumps virus.3 The normal incubation period
is from 16 to 18 days (range 12–25 days). In susceptible,
unimmunized populations, 60% to 70% of infections
are associated with parotitis.4 However, there
is a substantial subclinical attack rate produced by the mumps virus.
Approximately 20% of mumps infections may go unrecognized,
especially in adults, because they do not have evidence of parotitis.2,5 Given
the number of subclinical cases, information regarding a patient’s
history of mumps infection is notoriously inaccurate. Mumps virus
infection is most communicable from 1 to 2 days prior to parotid
swelling until 5 days after parotid swelling begins.2 Introduction
of infection onto a hospital ward in areas where vaccine is not
routinely given may lead to widespread nosocomial transmission because
some patients may develop subclinical infection, and patients are contagious
prior to onset of parotid swelling, making it extremely difficult
to prevent transmission.6
++
Introduction of an effective, live-attenuated virus vaccine (Jeryl Lynn
strain) in 1967, combined with the introduction of school laws regarding
mumps vaccination, led to a marked reduction in the number of reported
cases of mumps in the United States, from more than 185,000 cases
in 1968 to 2982 in 1985.7 Following a brief resurgence
of disease, a revised recommendation for two doses of measles-mumps-rubella
(MMR) vaccine in 19894 and subsequent changes in
school laws requiring two doses of vaccine, the annual number of
mumps cases further declined. From 2001 to 2005, fewer than 300 cases
of mumps were reported annually in the United States.8 In
2006, a multistate mumps outbreak with more than 5700 cases, many
involving older adolescents and young adults, demonstrated that
although two doses of vaccine were more protective than a single dose,
protection from infection, even with two doses of vaccine, was not
100%.5,9 Outside the United States, mumps remains
endemic in many countries throughout the world.10,11 In
2005, only 57% of World Health Organization member-countries
reportedly used mumps vaccine.11
++
A single attack of mumps is believed to confer permanent immunity
against a subsequent attack, regardless of whether ...