Mumps is generally a benign disease of children. The virus is spread via direct contact or by airborne droplets from the upper respiratory tract and requires significant contact for transmission.
Symptoms include non-specific myalgia, headache, malaise and low-grade fever followed by unilateral or bilateral swelling of the parotid glands. Illness completely resolves within one week.
In approximately 30% of the cases, infection passes without any symptoms at all.
Orchitis can occur in post-pubertal males, however sterility is very rare and there is no loss of hormonal function.
Oophoritis can occur in post-pubertal females, and symptoms include tenderness and pain, and can mimic appendicitis if the right ovary is involved. There is no evidence oorphoritis causes impaired fertility in females.
The Merck Manual, Ch. 19, Sec. 265
In 2006 there was an outbreak of mumps in the Midwest of U.S.
“Nearly 6,600 people became sick with the mumps, mostly in eight Midwest states, and the hardest-hit group was college students ages 18 to 24. Of those in that group who knew whether they had been vaccinated, 84 percent had had two mumps shots, according to the study by the Centers for Disease Control and Prevention and state health departments.”
http://www.usatoday.com/news/health/2008-04-09-3245946715_x.htm
In Minnesota there were 180 cases of mumps reported.
http://www.health.state.mn.us/divs/idepc/newsletters/dcn/sum06/mumps.html
Information was requested in regards to the vaccination status of these cases, which broke down as follows:
In the age groups:
< 18 years of age
18-24 year olds
25-49 year olds
> 50 year olds
In total there were:
29 with history of no vaccination (2 month old, too young to be vaccinated)
16 with history of vaccination, but number of doses unknown
22 with history of one dose
87 with history of two doses
4 with history of three doses
This information was received from the MDH and reported by Vaccine Awareness Minnesota.