Immunisation Horizon Scanning Volume 6 Issue 9

Influenza vaccination in patients with end-stage renal disease: Systematic review and assessment of quality of evidence related to vaccine efficacy, effectiveness and safety

Source: BMC Medicine doi:10.1186/s12916-014-0244-9

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Date of publication: December 2014

Publication Type: Research Article

In a nutshell: Background Vaccination against influenza is recommended in patients with end-stage renal disease (ESRD). However, so far, no systematic review has summarized the available evidence on the effectiveness and safety of influenza vaccination in this patient group.MethodsWe conducted a systematic review and meta-analysis and assessed the quality of evidence using the GRADE methodology. We searched MEDLINE, EMBASE, Cochrane Library databases, ClinicalTrials.gov, and reference lists for studies on efficacy, effectiveness, and/or safety of seasonal influenza vaccination in patients with ESRD receiving dialysis. All reported clinical outcomes were considered, including all-cause mortality, cardiac death, infectious death, all-cause hospitalization, hospitalization due to influenza or pneumonia, hospitalization due to bacteremia, viremia, or septicemia, hospitalization due to respiratory infection, ICU admission, and influenza-like illness.ResultsFive observational studies and no randomized-controlled trial were identified. In four studies, risk of bias was high regarding all reported outcomes. Strong residual confounding was likely to be present in one study reporting on three outcomes, as indicated by significant protective effects of vaccination outside influenza seasons. Therefore, the statistically significant protective effects on all-cause mortality (vaccine effectiveness (VE), 32%; 95% CI, 24?39%), cardiac death (VE, 16%; 95% CI, 1?29%), hospitalization due to influenza or pneumonia (VE, 14%; 95% CI, 7?20%), ICU admission (VE, 81%; 95% CI, 63?86%), and influenza-like illness (VE, 12%; 95% CI, 10?14%) have to be taken with caution. According to GRADE, the quality of the body of evidence was considered very low for all outcomes. No study reported on laboratory-confirmed influenza virus infections or on safety endpoints.ConclusionsEvidence on the protective effects of influenza vaccination in patients with ESRD is limited and of very low quality. Since VE estimates in the available literature are prone to unmeasured confounding, studies using randomization or quasi-experimental designs are needed to determine the extent by which vaccination prevents influenza and related clinical outcomes in this at-risk population. However, given the high rates of health-endangering events in these patients, even a low VE can be considered as sufficient to recommend annual influenza vaccination.

Length of publication: 21-pages

Does correcting myths about the flu vaccine work? An experimental evaluation of the effects of corrective information

Source: Vaccine Volume 33, Issue 3, Pages 459–464

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Date of publication: December 2014

Publication Type: Journal Article

In a nutshell: Seasonal influenza is responsible for thousands of deaths and billions of dollars of medical costs per year in the United States, but influenza vaccination coverage remains substantially below public health targets. One possible obstacle to greater immunization rates is the false belief that it is possible to contract the flu from the flu vaccine. A nationally representative survey experiment was conducted to assess the extent of this flu vaccine misperception. We find that a substantial portion of the public (43%) believes that the flu vaccine can give you the flu. We also evaluate how an intervention designed to address this concern affects belief in the myth, concerns about flu vaccine safety, and future intent to vaccinate. Corrective information adapted from the Centers for Disease Control and Prevention (CDC) website significantly reduced belief in the myth that the flu vaccine can give you the flu as well as concerns about its safety. However, the correction also significantly reduced intent to vaccinate among respondents with high levels of concern about vaccine side effects – a response that was not observed among those with low levels of concern. This result, which is consistent with previous research on misperceptions about the MMR vaccine, suggests that correcting myths about vaccines may not be an effective approach to promoting immunization.

Length of publication: 5-page

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