In 1984, a total of 3,021 cases of mumps were reported to CDC from 45 states. The incidence of 1.3 cases/100,000 population was the lowest reported since mumps became a nationally notifiable disease in 1968. This figure is 10% lower than the 1983 total of 3,355 cases and represents a 98% decrease from the total in 1968, the year after licensure of mumps vaccine. Twenty-five states reported fewer cases of mumps in 1984 than in 1983. The number of counties reporting cases of mumps decreased slightly between 1983 (726, 23.1%) and 1984 (700, 22.3%). Further declines in the incidence of reported mumps can be expected as more children entering school are required to provide proof of immunity to mumps. Estimated rates, by age group, United States, 1982-1984 *Rates were calculated by multiplying the percentage of cases with known age group by total reported cases and dividing by the population in the age group. Age-specific data were available for 2,654 (88%) of the cases reported for 1984. As in 1982 and 1983, approximately three-fourths of mumps patients of known age reported in 1984 were under 15 years of age. Children 5-9 years of age had the highest incidence (5.9/100,000 population) in 1984. Persons 10-14 years of age had the next highest incidence of disease. Together, children 5-14 years of age accounted for 61% of all cases with known age. Although the reported incidence rose 4% for persons 10-14 years of age and remained stable for persons 15-19 years of age, other age groups reported declines of 16%-18% compared with 1983. Age distribution and incidence of reported mumps cases, United States, *Reported number of cases per 100,000 population, extrapolated from the age distribution of cases with known age. 367 12.1 100.0 1.4 3,021 100.0 1.3 -43 PERTUSSIS (Whooping cough) — Rates, by year, United States, 1957-1984 25 30 10 Deaths -.04 5 Cases .02 0 8 8 8 8 1957 1960 1985 'Data not available for 1984. A total of 2,276 cases of pertussis were reported in the United States in 1984, a decrease of 8% from 1983. Between 1974 and 1984, the annual number of reported cases ranged from 1,010 to 2,463. Because of problems in the clinical and laboratory diagnosis of pertussis and because of different case criteria used by the individual states, it is likely that many cases of pertussis in the United States go unreported. |