As the data on worldwide deaths are starting to come in, our health prior to infection is the most important predictor of survival. In fact, the number one comorbidity in over 10% of deaths has been heart disease.
Here’s why. When we are infected with anything, our body has an increased metabolic demand to fight the infection. That means the body will ask the heart to do more. In the case of coronavirus, a lot more. The metabolic demands when we are infected with this sort of virus are typically four to eight times more than the normal workload on the heart. It’s kind of like running upstairs fast.
There is consensus among experts that both coronary artery disease and heart failure patients are at increased risk of acute events or exacerbations from viral respiratory infections, with other comorbidities (diabetes, obesity, hypertension, COPD, kidney disease) further increasing risk.
It’s been suggested that influenza may precipitate plaque rupture, increase cytokines that destabilise plaques and trigger the coagulation cascade, but clear causal mechanisms by which flu precipitates adverse events are unclear. Studies in mice showed that influenza virus directly infects atherosclerotic plaques and causes severe cellular inflammation at vascular levels. There is also solid evidence that influenza infection can increase the risk of acute coronary syndromes and several trials have shown that influenza vaccination can prevent myocardial infarctions.
The American Heart Association (AHA) secondary prevention guidelines recommend influenza vaccination as a measure to reduce risk of cardiovascular events.
chronic respiratory disease: 6.3%
cardiovascular disease: 10.5%