The increasing incidence of pertussis in Massachusetts adolescents and adults, 1989-1998

From 1989 to 1998, the incidence of pertussis increased in Massachusetts ad olescents and adults, reaching 71 and 5 per 100,000, respectively, by 1998, whereas the incidence in children remained stable. By 1998, 92% of cases o ccurred in adolescents and adults. Nationally, in contrast, adolescents and adults had incidences of only 5 and 0.8 per 100,000, respectively, and acc ounted for 47% of cases. The availability of a specific serologic test and active surveillance by public health personnel in Massachusetts are at leas t partial explanations. The rise in incidence may be real, however, because , as diagnostic efforts increased, the percentage of patients with a positi ve serologic test result also increased. Cases identified in adolescents an d adults were quire severe: 83% and 87%, respectively, experienced paroxysm al cough, 45% and 41% experienced vomiting, and 41% and 52% experienced a c ough lasting >4 weeks. Administration of acellular pertussis vaccine in the se age groups could prevent this substantial morbidity.