Prior to the vaccine, pancreatitis was reported in 3.5% of persons infected with mumps in one community during a two year period and was described in case reports.
Pancreatitis is infrequent, but occasionally occurs without parotitis; the hyperglycemia is transient and is reversible.
Although single instances of diabetes mellitus have been reported, a causal relationship with mumps virus infection has yet to be conclusively demonstrated; many cases of temporal association have been described both in siblings and individuals, and outbreaks of diabetes have been reported a few months or years after outbreaks of mumps.
In the prevaccine era, mumps caused transient deafness in 4.1% of infected adult males in a military population.
Permanent unilateral deafness caused by mumps occurred in 1 of 20,000 infected persons; bilateral, severe hearing loss was very rare. Mumps virus was isolated in 1945, and an inactivated vaccine was developed in