percent of all males with mumps contract orchitis (but 20 percent or more of males who develop mumps after puberty have orchitis) and only 13 percent of those with orchitis had impaired fertility attributable to mumps orchitis, mumps orchitis is not an important cause of sterility in males.
Penttinen and colleagues (1968) found that 15 to 25 percent of men who contracted mumps developed orchitis, and in about 10 to 20 percent of these men it was bilateral and, thus, had the potential to cause sterility. Two other studies have found that 30 to 38 percent of postpubertal males with mumps develop orchitis (Beard et al., 1977; Philip et al., 1959). They reported bilateral involvement in 17 and 37 percent of cases, respectively. Mumps orchitis was found to be most common in the second through fourth decades of life (Beard et al., 1977).
A review of the records of 2,482 patients with mumps (about half of whom were under 15 years of age) admitted to 16 infectious disease units in England and Wales revealed that 333 of 1,513 males developed orchitis and 71 males had orchitis and meningitis or encephalitis (Association for the Study of Infectious Disease, 1974). Interestingly, 5 of 969 females had oophoritis. The authors noted that orchitis was second only to CNS involvement as a complication of mumps. There were no recorded sequel, but the investigators did not attempt to follow up these patients for sterility because ''the practical difficulties associated with such a study are formidable'' (p. 555).
In 1954, Sandler reported azoospermia in a 34-year-old male who developed bilateral orchitis following mumps disease. Although his azoospermia persisted for over 1 year, he subsequently fathered a child.
In a retrospective study, McKendrick and Nishtar (1966) found that several men had fathered children following either unilateral or bilateral mumps orchitis.
Several authors concluded that since orchitis is usually unilateral, it is rarely a cause of permanent sterility (Association for the Study of Infectious Disease, 1974; Bendersky-Malbec, 1982; Penttinen et al., 1968; Werner, 1950b).
The data regarding mumps vaccine-associated orchitis in the literature are in two reports of surveillance for adverse reactions to immunization in other countries. Three cases of orchitis were reported following administration of MMR in Canada in 1987, for an incidence of 0.5 cases per 100,000 doses of MMR distributed (Koch et al., 1989). Six cases of suspected orchitis were reported following administration of measles or mumps (Jeryl Lynn strain) vaccine in the former West Germany from 1976 through 1989 (Fescharek et al., 1990). During that period of time an estimated 5.5 mil-