Influenza Vaccine Effectiveness in Preventing Hospitalization for Pneumonia in the Elderly

Abstract

During the winter of 1989-1990, influenza type A(H3N2) circulated widely, causing excess morbidity and mortality nationwide. From November through April, 1989-1990, hospitalized cases of pneumonia and influenza occurring among noninstitutionalized individuals 65 or more years of age were identified by 20 acute care hospitals in southern lower Michigan. These cases were group matched on age, sex, race, and zip code to randomly sampled, community-based controls from a comprehensive listing of Medicare beneficiaries residing in the study area. Self-reported data were collected from cases and controls on influenza vaccine status for the 1989-1990 season and on a number of other factors which could have influenced vaccination status or outcome. Questionnaires were completed by 1,907 individuals, 449 of whom were cases, resulting in an overall response rate of 76%. A community-based influenza surveillance system was implemented to determine the timing and intensity of viral activity and influenza-like illness. Vaccine effectiveness in preventing overall pneumonia and influenza hospitalizations was estimated by logistic regression. During the 3-month period of surveillance-confirmed peak influenza type A(H3N2) circulation, vaccine effectiveness was 45% (95% confidence interval 14-64, p = 0.009). However, during the 3-month period of low or absent virus activity, identical methodology and model specification resulted in an effectiveness estimate of 21% that was not statistically different from zero (p = 0.36). The effectiveness determined during the peak period of virus circulation is felt to be a conservative estimate, since agents other than influenza are responsible for pneumonia and influenza hospitalizations, even during times of peak influenza activity.

Efficacy of the Influenza Vaccine in Patients with Malignant Lymphoma

“…Age range in the control group was 35-82 years of age (median age 61 years). Subjects were excluded from eligibility into the study if they had a history of the following: (1) known or suspected allergy to eggs or egg products, (2) received immunoglobulins within the previous 90 days prior to vaccination or would be receiving immunoglobulins during the 60 days post-vaccination, (3) had a bone marrow or solid organ transplant, (4) planning to receive another vaccine during the study period, (5) were receiving corticosteroids (7.5 mg of prednisone minimum dose or its equivalent), (6) had an acute febrile illness at the time of vaccination, (7) Guillain-Barré syndrome, (8) neutropenia as defined by a white blood cell count of <1.0 x 10 9 /l or lymphopenia defined as a lymphocyte count of 1.0 x 10 9 /l. Twenty-one of the lymphoma patients in the case group were in the process of receiving chemotherapy; 8 had completed their chemotherapy within 3 months of entrance into the study.…”

“…These symptoms are frequently experienced in association with a host of other viral infections. [4][5][6][7][8][9][10][11][12][13][14][15][16] Few of these studies document actual influenza viral infection by using direct fluorescence antibody testing, polymerase chain reaction (PCR) analysis and cell culture techniques to isolate and identify the virus.…”

Effect of social factors on winter hospital admission for respiratory disease: a case–control study of older people in the UK

“…This is consistent with other studies showing independent risks of COPD and heart disease. 14,15,18,20,21,[33][34][35] Patients with multiple hospitalisations in the previous year also had significantly increased risk. This is concordant with two other small studies of COPD admissions, 16,17 but not with the lack of effect seen in two case-control studies of pneumonia admissions.…”

Vacinas e o trato respiratório: o que devemos saber?

“…Esses fatos são bem conhecidos nos idosos maiores de 60 anos de idade 39 , bem como nas populações de risco para maior gravidade da infecção por influenza, definidas pelos portadores de doenças cardiopulmonares 40 e pacientes com imunossupressão 41 . Além destes, outras populações vêm sendo consideradas como de maior risco para complicações e hospitalizações nas epidemias de influenza, tais como gestantes e portadores de doenças metabólicas 42 .…”