Trivalent inactivated influenza vaccine is not associated with sickle cell hospitalizations in adults from a large cohort
Institute for Health Research, Kaiser Permanente Colorado, Denver, CO, USA.Vaccine (Impact Factor: 3.62). 09/2011; 29(46):8179-81. DOI: 10.1016/j.vaccine.2011.09.002
We evaluated the risk of hospitalization for sickle cell crisis (SCC) following influenza vaccination (trivalent inactivated vaccine, TIV) in adults with sickle cell disease. The cohort consisted of all adults aged 18years and older who had a diagnosis of sickle cell disease in the Vaccine Safety Datalink from 1991 to 2006. The outcome measure was any hospitalization for SCC with the main exposure being influenza vaccine. We used a self controlled case series design to compare the incidence rates of hospitalization for SCC during the exposed and unexposed periods after TIV. No significant association between influenza vaccination and hospitalization for sickle cell crisis was found (IRR ratio 0.92, 95% confidence limits 0.66-1.28). These results provide evidence that the seasonal influenza vaccine is safe as recommended in adults who are at high risk for complications of influenza sequelae due to sickle cell disease.
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ABSTRACT: Large observational vaccine safety studies often use automated diagnoses extracted from medical care databases to identify pre-specified potential adverse events following immunization (AEFI). We assessed the secular trends and variability in the number of diagnoses per encounter regardless of immunization status referred as diagnostic code density, by healthcare setting, age, and pre-specified condition in eight large health care systems of the Vaccine Safety Datalink project during 2001-2009. An increasing trend in diagnostic code density was observed in all healthcare settings and age groups, with variations across the sites. Sudden increases in diagnostic code density were observed at certain sites when changes in coding policies or data inclusion criteria took place. When vaccine safety studies use an historical comparator, the increased diagnostic code density over time may generate low expected rates (based on historical data) and high observed rates (based on current data), suggesting a false positive association between a vaccine and AEFI. The ongoing monitoring of the diagnostic code density can provide guidance on study design and choice of appropriate comparison groups. It can also be used to ensure data quality and allow timely correction of errors in an active safety surveillance system.Vaccine 12/2012; 31(7). DOI:10.1016/j.vaccine.2012.12.030 · 3.62 Impact Factor
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ABSTRACT: Background: Children with sickle cell disease (SCD) are susceptible to recurrent infections, which are often life threatening and necessitate frequent vaccinations. Given the altered baseline immunity and proinflammatory state associated with SCD, we sought to determine the relative safety and efficacy of vaccination in transgenic SCD mice. Methods: Eight-week-old SCD mice were vaccinated with ovalbumin and aluminum hydroxide weekly for 3 wk by the intraperitoneal or intramuscular route. One week after the third vaccination, serum cytokines/chemokines, immunoglobulins, and bronchoalveolar lavage fluid cytokines were measured. Results: Only SCD mice were prone to mortality associated with vaccination, as 40% of the animals died after the intraperitoneal vaccinations and 50% died after the intramuscular vaccinations. Serum IgG2b and IgM were significantly lower in SCD mice than in C57BL/6 mice after vaccination, but ovalbumin-specific IgE was significantly higher. Serum interleukin (IL)-1α, IL-2, IL-5, macrophage inflammatory protein 1α, and granulocyte macrophage-colony stimulating factor were significantly lower in SCD mice than in C57BL/6 mice after vaccination, whereas bronchoalveolar lavage fluid IL-1β and IL-6 were increased. Conclusion: Mice with SCD appear to have a dysregulated immune response to vaccination. Thus, the relative safety and immunogenicity of vaccination should be studied in greater detail in the context of SCD.Pediatric Research 05/2013; 74(2). DOI:10.1038/pr.2013.85 · 2.31 Impact Factor
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ABSTRACT: Background: Concerns about vaccine safety have led some parents to decline recommended vaccination of their children, leading to the resurgence of diseases. Reassurance of vaccine safety remains critical for population health. This study systematically reviewed the literature on the safety of routine vaccines recommended for children in the United States. Methods: Data sources included PubMed, Advisory Committee on Immunization Practices statements, package inserts, existing reviews, manufacturer information packets, and the 2011 Institute of Medicine consensus report on vaccine safety. We augmented the Institute of Medicine report with more recent studies and increased the scope to include more vaccines. Only studies that used active surveillance and had a control mechanism were included. Formulations not used in the United States were excluded. Adverse events and patient and vaccine characteristics were abstracted. Adverse event collection and reporting was evaluated by using the McHarm scale. We were unable to pool results. Strength of evidence was rated as high, moderate, low, or insufficient. Results: Of 20 478 titles identified, 67 were included. Strength of evidence was high for measles/mumps/rubella (MMR) vaccine and febrile seizures; the varicella vaccine was associated with complications in immunodeficient individuals. There is strong evidence that MMR vaccine is not associated with autism. There is moderate evidence that rotavirus vaccines are associated with intussusception. Limitations of the study include that the majority of studies did not investigate or identify risk factors for AEs; and the severity of AEs was inconsistently reported. Conclusions: We found evidence that some vaccines are associated with serious AEs; however, these events are extremely rare and must be weighed against the protective benefits that vaccines provide.Pediatrics 08/2014; 134(2):325-337. DOI:10.1542/peds.2014-1079 · 5.47 Impact Factor
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