During the evaluation period, 2009 H1N1 influenza caused severe illness requiring hospitalization, including pneumonia and death. Nearly three quarters of the patients had one or more underlying medical conditions. Few severe illnesses were reported among persons 65 years of age or older. Patients seemed to benefit from antiviral therapy.

No abstract

Background: The authors sought to monitor the impact of widespread varicella vaccination on the epidemiology of varicella and herpes zoster. While varicella incidence would be expected to decrease, mathematical models predict an initial increase in herpes zoster incidence if re-exposure to varicella protects against reactivation of the varicella zoster virus.

Pertussis causes significant morbidity in and costs for adolescents and adults, with time losses comprising the largest proportion of the cost. Societal costs should be considered when making decisions about potential vaccine use in the future.

From 1989 to 1998, the incidence of pertussis increased in Massachusetts adolescents and adults, reaching 71 and 5 per 100,000, respectively, by 1998, whereas the incidence in children remained stable. By 1998, 92% of cases occurred in adolescents and adults. Nationally, in contrast, adolescents and adults had incidences of only 5 and 0.8 per 100,000, respectively, and accounted for 47% of cases. The availability of a specific serologic test and active surveillance by public health personnel in Massachusetts are at least partial explanations. The rise in incidence may be real, however, because, as diagnostic efforts increased, the percentage of patients with a positive serologic test result also increased. Cases identified in adolescents and adults were quite severe: 83% and 87%, respectively, experienced paroxysmal cough, 45% and 41% experienced vomiting, and 41% and 52% experienced a cough lasting >4 weeks. Administration of acellular pertussis vaccine in these age groups could prevent this substantial morbidity.