Research
Mumps and mumps vaccine: a global review
A.M. Galazka,1 S.E. Robertson, 2 & A. Kraigher 3
Introduction
Mumps is an acute infectious disease caused by a
paramyxovirus closely related to parainfluenza virus.
Although the disease is usually mild, its burden
should not be underestimated. Up to 10% of mumps
patients developed aseptic meningitis; a less common
but more serious complication is encephalitis,
which can result in death or disability; and permanent
deafness, orchitis and pancreatitis are other
untoward effects that can be prevented by vaccination.
As of mid-1998, mumps vaccine was routinely
used by national childhood immunization programmes
in 82 countries. Where high coverage has
been achieved, countries have shown a rapid decline
in mumps morbidity. Furthermore, in many countries
encephalitis associated with mumps has almost
totally vanished.
In this article we review the disease burden
caused by mumps; summarize studies on the
immunogenicity, efficacy, and safety of different
strains of mumps vaccine; and highlight lessons
learned about implementing mumps immunization
from countries in different regions of the world.
Guidance is provided for countries contemplating
the introduction of mumps vaccine and for countries
already using this vaccine.
Disease burden due to mumps
Humans are the only natural hosts for mumps virus,
which is usually spread by respiratory droplets.
The incubation period of mumps averages 16–18
days, with a range of about 2–4 weeks (1). Infection
with mumps virus is asymptomatic in one-third of
cases. Nonspecific prodromal symptoms include lowgrade
fever, anorexia, malaise, and headache. The
disease can vary from a mild upper respiratory illness
to viraemia with widespread systemic involvement
(Table 1). Classic mumps is characterized by
enlargment of the parotid and other salivary glands;
parotitis is bilateral in three-quarters of cases; and
other salivary glands are involved in 10% of cases
(1).
Epididymo-orchitis occurs in about 25% of
postpubertal men who contract mumps. In one large
cohort study the median age for mumps orchitis was
29 years (range, 11–64 years) (2). Testicular atrophy
occurs in about one-third of patients with
mumps orchitis, but sterility is rare. Mumps orchitis
appears to be a risk factor for testicular cancer,
though not