Abhijit Sen1,2, Inger Johanne Bakken3,4, Ragna Elise Støre Govatsmark5,6, Torunn Varmdal6, Kaare Harald Bønaa7,8,9, Kenneth Jay Mukamal10, Siri Eldevik Håberg3, Imre Janszky5,11. 1. Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Håkon Jarls gate 11 and Mauritz Hanssens gate, 7491, Trondheim, Norway. abhijit.sen@ntnu.no. 2. Center for Oral Health Services and Research (TkMidt), Trondheim, Norway. abhijit.sen@ntnu.no. 3. Centre for Fertility and Health (CeFH), Norwegian Institute of Public Health, Oslo, Norway. 4. Norwegian Directorate of Health, Trondheim, Norway. 5. Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Håkon Jarls gate 11 and Mauritz Hanssens gate, 7491, Trondheim, Norway. 6. Department of Medical Quality Registries, St. Olav's University Hospital, Trondheim, Norway. 7. Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. 8. Clinic for Heart Disease, St. Olav's University Hospital, Trondheim, Norway. 9. Department of Community Medicine, UiT Arctic University of Norway, Tromsø, Norway. 10. Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA. 11. Regional Center for Health Care Improvement, St Olav's Hospital, Trondheim, Norway.
Abstract
BACKGROUND: US and European guidelines diverge on whether to vaccinate adults who are not at high risk for cardiovascular events against influenza. Here, we investigated the associations between influenza vaccination and risk for acute myocardial infarction, stroke and pulmonary embolism during the 2009 pandemic in Norway, when vaccination was recommended to all adults. METHODS: Using national registers, we studied all vaccinated Norwegian individuals who suffered AMI, stroke, or pulmonary embolism from May 1, 2009 through September 30, 2010. We defined higher-risk individuals as those using anti-diabetic, anti-obesity, anti-thrombotic, pulmonary or cardiovascular medications (i.e. individuals to whom vaccination was routinely recommended); all other individuals were regarded as having lower-risk. We estimated incidence rate ratios with 95% CI using conditional Poisson regression in the pre-defined risk periods up to 180 days following vaccination compared to an unexposed time-period, with adjustment for season or daily temperature. RESULTS: Overall, we observed lower risk for cardiovascular events following influenza vaccination. When stratified by baseline risk, we observed lower risk across all three outcomes in association with vaccination among higher-risk individuals. In this subgroup, relative risks were 0.72 (0.59-0.88) for AMI, 0.77 (0.59-0.99) for stroke, and 0.73 (0.45-1.19) for pulmonary embolism in the period 1-14 days following vaccination when compared to the background period. These associations remained essentially the same up to 180 days after vaccination. In contrast, the corresponding relative risks among subjects not using medications were 4.19 (2.69-6.52), 1.73 (0.91-3.31) and 2.35 (0.78-7.06). CONCLUSION: In this nationwide study, influenza vaccination was associated with overall cardiovascular benefit. This benefit was concentrated among those at higher cardiovascular risk as defined by medication use. In contrast, our results demonstrate no comparable inverse association with thrombosis-related cardiovascular events following vaccination among those free of cardiovascular medications at baseline. These results may inform the risk-benefit balance for universal influenza vaccination.
BACKGROUND: US and European guidelines diverge on whether to vaccinate adults who are not at high risk for cardiovascular events against influenza. Here, we investigated the associations between influenza vaccination and risk for acute myocardial infarction, stroke and pulmonary embolism during the 2009 pandemic in Norway, when vaccination was recommended to all adults. METHODS: Using national registers, we studied all vaccinated Norwegian individuals who suffered AMI, stroke, or pulmonary embolism from May 1, 2009 through September 30, 2010. We defined higher-risk individuals as those using anti-diabetic, anti-obesity, anti-thrombotic, pulmonary or cardiovascular medications (i.e. individuals to whom vaccination was routinely recommended); all other individuals were regarded as having lower-risk. We estimated incidence rate ratios with 95% CI using conditional Poisson regression in the pre-defined risk periods up to 180 days following vaccination compared to an unexposed time-period, with adjustment for season or daily temperature. RESULTS: Overall, we observed lower risk for cardiovascular events following influenza vaccination. When stratified by baseline risk, we observed lower risk across all three outcomes in association with vaccination among higher-risk individuals. In this subgroup, relative risks were 0.72 (0.59-0.88) for AMI, 0.77 (0.59-0.99) for stroke, and 0.73 (0.45-1.19) for pulmonary embolism in the period 1-14 days following vaccination when compared to the background period. These associations remained essentially the same up to 180 days after vaccination. In contrast, the corresponding relative risks among subjects not using medications were 4.19 (2.69-6.52), 1.73 (0.91-3.31) and 2.35 (0.78-7.06). CONCLUSION: In this nationwide study, influenza vaccination was associated with overall cardiovascular benefit. This benefit was concentrated among those at higher cardiovascular risk as defined by medication use. In contrast, our results demonstrate no comparable inverse association with thrombosis-related cardiovascular events following vaccination among those free of cardiovascular medications at baseline. These results may inform the risk-benefit balance for universal influenza vaccination.
Authors: Siri E Håberg; Lill Trogstad; Nina Gunnes; Allen J Wilcox; Håkon K Gjessing; Sven Ove Samuelsen; Anders Skrondal; Inger Cappelen; Anders Engeland; Preben Aavitsland; Steinar Madsen; Ingebjørg Buajordet; Kari Furu; Per Nafstad; Stein Emil Vollset; Berit Feiring; Hanne Nøkleby; Per Magnus; Camilla Stoltenberg Journal: N Engl J Med Date: 2013-01-16 Impact factor: 91.245
Authors: Liam Smeeth; Sara L Thomas; Andrew J Hall; Richard Hubbard; Paddy Farrington; Patrick Vallance Journal: N Engl J Med Date: 2004-12-16 Impact factor: 91.245