Influenza vaccines for preventing cardiovascular disease

Abstract

BACKGROUND: This is an update of the original review published in 2008. The risk of adverse cardiovascular outcomes is increased with influenza-like infection, and vaccination against influenza may improve cardiovascular outcomes. OBJECTIVES: To assess the potential benefits of influenza vaccination for primary and secondary prevention of cardiovascular disease. METHODS: Search methods: We searched the following electronic databases on 18 October 2013: The Cochrane Library (including Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Economic Evaluation Database (EED) and Health Technology Assessment database (HTA)), MEDLINE, EMBASE, Science Citation Index Expanded, Conference Proceedings Citation Index - Science and ongoing trials registers (www.controlled-trials.com/ and www.clinicaltrials.gov). We examined reference lists of relevant primary studies and systematic reviews. We performed a limited PubMed search on 20 February 2015, just before publication. Selection criteria: Randomised controlled trials (RCTs) of influenza vaccination compared with placebo or no treatment in participants with or without cardiovascular disease, assessing cardiovascular death or non-fatal cardiovascular events. Data collection and analysis: We used standard methodological procedures as expected by The Cochrane Collaboration. We carried out meta-analyses only for cardiovascular death, as other outcomes were reported too infrequently. We expressed effect sizes as risk ratios (RRs), and we used random-effects models. MAIN RESULTS: We included eight trials of influenza vaccination compared with placebo or no vaccination, with 12,029 participants receiving at least one vaccination or control treatment. We included six new studies (n = 11,251), in addition to the two included in the previous version of the review. Four of these trials (n = 10,347) focused on prevention of influenza in the general or elderly population and reported cardiovascular outcomes among their safety analyses; four trials (n = 1682) focused on prevention of cardiovascular events in patients with established coronary heart disease. These populations were analysed separately. Follow-up continued between 42 days and one year. Five RCTs showed deficits in at least three of the risk of bias criteria assessed. When reported (seven studies), vaccination provided adequate immunogenicity or protection against influenza. Cardiovascular mortality was reported by four secondary prevention trials and was significantly reduced by influenza vaccination overall (risk ratio (RR) 0.45, 95% confidence interval (CI) 0.26 to 0.76; P value 0.003) with no significant heterogeneity between studies, and by three trials reporting cardiovascular mortality as part of their safety analyses when the numbers of events were too small to permit ...

Stroke Risk Factors, Genetics, and Prevention

“…A Cochrane review of eight randomized controlled trials with a total of 12,029 participants provides evidence that influenza vaccination decreased cardiovascular outcomes, and a case series study that used a within-person method of comparison found that the risk of stroke was increased after respiratory tract infection but was reduced after vaccination against influenza, pneumococcal infection and tetanus. 168,169 On the basis of this evidence, annual vaccination against influenza may affect stroke rates and could be given to individuals who are at moderate to high risk of stroke, as emphasized in recent guidelines.…”

Design and rationale for the I nfluenza vaccination A fter M yocardial I nfarction (IAMI) trial. A registry-based randomized clinical trial

“…Influenza vaccination is guideline recommended by the American Heart Association and the American College of Cardiology (Class I, level of evidence B recommendation) (34) and "may be considered" according to The European Society of Cardiology (Class IIb, level of evidence C) (35). When all available information on the subject was condensed in a Cochrane review the conclusion was that additional higher-quality evidence is necessary to confirm whether influenza vaccination is effective in preventing cardiovascular disease (18).…”

“…The need for such a study was highlighted in a Cochrane review concluding that additional higher-quality evidence is necessary to confirm whether influenza vaccination is effective in preventing cardiovascular disease (18).…”

Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community‐acquired pneumonia

“…Similarly, for influenza vaccination there have been a number of studies , and some reviews , including systematic reviews and meta‐analyses investigating its potential efficacy in preventing acute cardiac events. Influenza vaccination has been reported to reduce (i) the development of a new AMI in patients with chronic heart disease ; (ii) the incidence of AMI in the 60 days following vaccination, compared to the baseline period ; and (iii) the frequency of coronary ischaemic events in patients with optimally treated coronary artery disease .…”

“…Whilst the review articles generally indicated benefit of influenza vaccination in reducing the incidence of AMI, one did indicate that vaccination rates still remained low . The authors of a systematic review and meta‐analysis concluded that in patients with CVD, influenza vaccination appeared to reduce composite CVEs compared to placebo, but not individual outcomes such as AMI, and there was not enough evidence to determine whether vaccination was effective in primary prevention . However, the authors also indicated that since most studies had some risk of bias, further higher quality evidence was required to confirm the findings.…”