High Risk For Influenza Complications Research Articles

Nuevas indicaciones de la vacuna inactivada antigripal en la población infantil (2004-2005)

Several epidemiological studies have indicated that, in all countries and in distinct epidemic years, the highest rates of influenza infection (between 15% and 42%) occur in the pediatric population, especially in school-aged children. Over various influenza seasons, the rates of annual outpatient visits attributable to influenza vary from 6-29% of children. Influenza and its complications have been reported to result in a 10-30% increase in the number of antibiotic courses prescribed to children during the influenza season. Current percentages of influenza vaccination in children are very low, although the hospitalization rates for infectious complications in children under 5 years are at least equal to those observed in individuals aged more than 65 years. The reasons for these low immunization rates are unknown, but many factors could be involved, especially the need for annual revaccination. In 2003 the Advisory Committee on Immunization Practices (ACIP) recommended influenza immunization only in children at high risk for influenza complications and in those living with someone in a high-risk group. However, they encouraged vaccination of all children aged 6-23 months old. After a review of various epidemiological studies, in 2004 both the ACIP and the American Academy of Pediatrics recommended systematic immunization of all healthy children within this age group. However, both institutions advise that before the routine introduction of influenza immunization in all children aged 6-23 months old, immunization programs in high-risk children need to be implemented.

Preferred provider organization claims showed high predictive value but missed substantial proportion of adults with high-risk conditions

Background and Objective We assessed the validity and utility of a claims-based ICD-9-CM algorithm for identifying preferred provider organization (PPO) enrollees ages 18–64 years at high risk for influenza complications. Methods PPO enrollees with ≥2 encounters in an ambulatory setting or ≥1 encounters in an inpatient or emergency room setting with ICD-9-CM diagnosis codes for the high-risk conditions were considered algorithm positive. Stratified random sampling was used to select 1,001 algorithm-positive and 330 algorithm-negative enrollees for medical chart abstractions. Results The prevalence of high-risk conditions using claims data was 2.5% compared to 18.2% according to medical records. The algorithm had a sensitivity of 12% and a specificity of 99%. Positive and negative predictive values were 87 and 84%, respectively. Sensitivity was twofold higher among adults aged 50–64 years than among younger adults (17 vs. 9%). Applying an algorithm definition of ≥1 encounters in any setting resulted in an increased sensitivity, but captured a higher proportion of false positives. Conclusion A claims-positive record was highly indicative of the presence of high-risk conditions, but such claims missed a large proportion of PPO enrollees with high-risk conditions. It is important to assess the validity of administrative data in different age groups.

Oral oseltamivir reduces febrile illness in patients considered at high risk of influenza complications

Background: Influenza poses a serious burden to patients at high risk of influenza complications and vaccination against the disease may be inadequate due to poor uptake rates or impaired immune response. We investigated the efficacy and safety of oral oseltamivir treatment in two studies of elderly patients or those with underlying cardiac/pulmonary disease (at-risk). Methods: 1138 high-risk patients (13–97 years) presenting within 36 h of onset of influenza symptoms were randomized to oseltamivir 75 mg or placebo bid for 5 days. Endpoints included duration of febrile illness, fever and other symptoms, viral shedding and complications. Results: 727 (64%) patients were influenza-infected (ITTI) (at-risk: placebo 133, oseltamivir 118; elderly: placebo 254, oseltamivir 222). In the ITTI population, oseltamivir reduced median duration of fever by 37% in at-risk patients and by 25% in elderly patients compared with placebo. Acute febrile illness and respiratory complications were reduced with oseltamivir treatment by approximately 30% in both patient populations. Viral shedding was reduced by 70% in oseltamivir-treated at-risk patients. Oseltamivir was well tolerated, with similar incidence of gastrointestinal events reported in placebo and oseltamivir recipients. Conclusions: Oseltamivir reduces the duration of fever, febrile illness, individual influenza symptoms and complications in high-risk patients.

Should We Revaccinate Seasoned Globe-Trotters for Influenza?

Global travel may increase the risk for contracting influenza. The Canadian National Advisory Committee on Immunization has recommended influenza vaccination for people at high risk for influenza complications who are traveling to destinations with circulating influenza. The known protective antibody effect of influenza vaccination peaks at 4 to …