Acute myocardial infarctions and stroke triggered by laboratory-confirmed respiratory infections in Denmark, 2010 to 2016

Background: Several studies have investigated a possible association between respiratory infection and acute myocardial infarction (MI). As both influenza and pneumococcal infections are vaccine preventable, understanding the populations affected by virus-induced cardiovascular complications is important to guide public health and clinical practice. Aim: This observational study aimed to quantify the association between laboratory-confirmed respiratory bacteria or virus infections and risk of first MI or stroke, by using self-controlled case series (SCCS) analysis of anonymised linked electronic Danish health records. Methods: The SCCS method was used to determine the relative incidence of the first event of MI and stroke occurring within 28days after laboratory-confirmed respiratory infections compared with the baseline time period. Results: In the age and season adjusted analyses for first acute MI, the incidence ratios (IR) of a MI event occurring during the risk period were significantly elevated following a Streptococcus pneumoniae infection with values of 20.1, 11.0 and 4.9 during 1-3, 4-7 and 8-14days, respectively and following respiratory virus infection with values of 15.2, 4.5 and 4.4 during 1-3, 8-14 and 15-28days, respectively. The significantly elevated IRs for stroke following an S. pneumoniae infection were 25.5 and 6.3 during 1-3 and 8-14days, respectively and following respiratory virus infection 8.3, 7.8 and 6.2 during 1-3, 4-7 and 8-14days, respectively. Conclusion: This study suggested a significant cardiovascular event triggering effect following infection with S. pneumoniae and respiratory viruses (mainly influenza), indicating the importance of protection against vaccine-preventable respiratory infections.