Sir.—I previously reported four cases of mumps in adolescents whom I had previously vaccinated with mumps virus vaccine in early childhood.1 In that report, I raised the question of the possible need for booster doses of mumps vaccine in children approaching puberty.
Since the start of 1986, there has been a marked increase in cases of mumps in the Chicago area. From January 1986 through the middle of November 1986, there were 1750 cases of mumps reported to the Board of Health of Chicago (mostly by schools and hospital clinics). The actual number in the Chicago area far exceeds this reported number since most physicians in private practice do not report cases of mumps.
The age distribution of the reported cases were as follows: 0 to 5 years, 298 cases; 6 to 10 years, 595 cases; 11 to 15 years, 640 cases; 16 to 20 years, 83 cases;