Influenza vaccination lowers CVD riskLiterature - Udell JA, et al. JAMA Oct 2013 - JAMA. 2013;310:1711-1720.
Association Between Influenza Vaccination and Cardiovascular Outcomes in High-Risk Patients
Udell JA, Zawi R, Bhatt DL, et al.
BackgroundAs winter, and the flu season, is coming, there remains interest in a potential association between respiratory tract infections, of which influenza and influenza-like illnesses are common causes, [1,2] and subsequent cardiovascular events.[3-9] Seasonal influenza-like illnesses may explain a major determinant of the timing of acute thrombotic vascular events in patients with previously stable coronary artery disease (CAD) and cerebrovascular disease.
Accumulating data suggest that an annual influenza vaccination can protect against cardiovascular disease events, particularly in high-risk individuals with existing coronary heart disease. [4,10-19]
Medical association guidelines recommend universal vaccination in patients with, or at risk of, cardiovascular disease for protection from general influenza complications, largely based on observational findings.
This study is a systematic review and meta-analysis of six randomized, controlled clinical trials of influenza vaccine studying cardiovascular events as efficacy or safety outcomes.
The trials analyzed covered 6,735 patients (mean age, 67 years; 51.3% women; 36.2% with cardiac history; mean follow-up time, 7.9 years). The primary endpoint was a composite of major adverse CV events, including CV death or hospitalization for MI, unstable angina, stroke, HF and urgent coronary revascularization within 12 months of follow-up. The secondary endpoint was CV mortality and other individual CV events within 12 months of follow-up.
- People who received the flu vaccine had a significantly lower risk of cardiovascular events.
- Influenza vaccination was associated with a 36% lower risk of cardiovascular events: cardiovascular events occurred in 2.9% of people in the vaccination group versus 4.7% of controls (RR 0.64, CI 0.48-0.86, P =0 .003).
- 58 people would need to be vaccinated to prevent 1 major cardiovascular event.
- The protective effect was largely restricted to people who had had a recent acute coronary syndrome (ACS): the influenza vaccine was associated with 55% lower risk of major adverse cardiovascular events in patients with a recent acute coronary syndrome (ACS)
- RR for patients with recent ACS: 0.45 [95% CI, 0.32-0.63]
- RR for patients without recent ACS: 0.94 [95% CI, 0.55-1.61] recent ACS (P for interaction =0.02).
- In ACS patients, eight patients would need to be treated with the influenza vaccine to prevent one major cardiovascular event.
- Results were similar with the addition of unpublished data.
ConclusionIn this meta-analysis, influenza vaccination was associated with a lower risk of major adverse cardiovascular events within 1 year, particularly in patients with recent ACS. Future research with an adequately powered multicenter trial to confirm the efficacy of this low-cost, annual, safe, easily administered, and well-tolerated therapy to reduce cardiovascular risk beyond current therapies is warranted.
Editorial comment (20)More than half of people under the age of 65, and as many as one-third of people over the age of 65, don’t receive annual flu vaccines. One of the most consistent and relevant findings of operational research is that recommendation for vaccination from physicians and other health care professionals is a strong predictor of vaccine acceptance and receipt among patients… all health care practitioners can therefore recommend influenza vaccine to their patients.
1. Lim WS, Macfarlane JT, Boswell TC, et al. Study of community acquired pneumonia aetiology (SCAPA) in adults admitted to hospital: implications for management guidelines. Thorax. 2001;56(4): 296-301.
2. Rubin MA, Ford LC, Gonzales R. Pharyngitis, sinusitis, otitis, and other upper respiratory tract infections. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J, eds. Harrison's Principles of Internal Medicine. 18th ed. New York, NY:McGraw-Hill; 2012.
3. Smeeth L, Thomas SL, Hall AJ, Hubbard R, Farrington P, Vallance P. Risk of myocardial infarction and stroke after acute infection or vaccination. N Engl J Med. 2004;351(25):2611-2618.
4. Nichol KL, Margolis KL, Wuorenma J, Von Sternberg T. The efficacy and cost effectiveness of vaccination against influenza among elderly persons living in the community. N Engl J Med. 1994;331(12):778-784.
5. Bainton D, Jones GR, Hole D. Influenza and ischaemic heart disease—a possible trigger for acute myocardial infarction? Int J Epidemiol. 1978;7(3):231-239.
6. Madjid M, Aboshady I, Awan I, Litovsky S, Casscells SW. Influenza and cardiovascular disease: is there a causal relationship? Tex Heart Inst J. 2004;31(1):4-13.
7. Warren-Gash C, Smeeth L, Hayward AC. Influenza as a trigger for acute myocardial infarction or death from cardiovascular disease: a systematic review. Lancet Infect Dis. 2009;9(10):601-610.
8. Warren-Gash C, Bhaskaran K, Hayward A, et al. Circulating influenza virus, climatic factors, and acute myocardial infarction: a time series study in England and Wales and Hong Kong. J Infect Dis. 2011;203(12):1710-1718.
9. Corrales-Medina VF, Musher DM, Shachkina S, Chirinos JA. Acute pneumonia and the cardiovascular system. Lancet. 2013;381(9865): 496-505.
10. Naghavi M, Barlas Z, Siadaty S, Naguib S, Madjid M, Casscells W. Association of influenza vaccination and reduced risk of recurrent myocardial infarction. Circulation. 2000;102(25):3039-3045.
11. Siscovick DS, Raghunathan TE, Lin D, et al. Influenza vaccination and the risk of primary cardiac arrest. Am J Epidemiol. 2000;152(7): 674-677.
12. Lavallée P, Perchaud V, Gautier-Bertrand M, Grabli D, Amarenco P. Association between influenza vaccination and reduced risk of brain infarction. Stroke. 2002;33(2):513-518.
13. Nichol KL, Nordin J, Mullooly J, Lask R, Fillbrandt K, Iwane M. Influenza vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly. N Engl J Med. 2003;348(14):1322-1332.
14. Grau AJ, Fischer B, Barth C, Ling P, Lichy C, Buggle F. Influenza vaccination is associated with a reduced risk of stroke. Stroke. 2005;36(7):1501- 1506.
15. Madjid M, Miller CC, Zarubaev VV, et al. Influenza epidemics and acute respiratory disease activity are associated with a surge in autopsy-confirmed coronary heart disease death: results from 8 years of autopsies in 34 892 subjects. Eur Heart J. 2007;28(10):1205-1210.
16. Nichol KL, Nordin JD, Nelson DB, Mullooly JP, Hak E. Effectiveness of influenza vaccine in the community-dwelling elderly. N Engl J Med. 2007;357(14):1373-1381.
17. Hung IF, Leung AY, Chu DW, et al. Prevention of acute myocardial infarction and stroke among elderly persons by dual pneumococcal and influenza vaccination: a prospective cohort study. Clin Infect Dis. 2010;51(9):1007-1016.
18. Siriwardena AN, Gwini SM, Coupland CA. Influenza vaccination, pneumococcal vaccination, and risk of acute myocardial infarction: matched case-control study. CMAJ. 2010;182(15):1617-1623.
19. Macintyre CR, Heywood AE, Kovoor P, et al. Ischaemic heart disease, influenza, and influenza vaccination: a prospective case control study. Heart. 2013.
20. Neuzil KM. Influenza Vaccination in 2013-2014. JAMA. 2013;310:1681-1682.