Abstract
Besides advanced age and the presence of multiple comorbidities as major contributors to increased risk of severe disease and fatal outcome from Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19), there is now emerging evidence that overweight and obesity predispose to severe symptoms and negative prognosis. Remarkably, the severity of COVID-19 appears to rise with increasing body mass index (BMI). The association between COVID-19 outcomes and overweight/obesity has biological and physiological plausibility. Potential pathophysiological mechanisms that may explain this strong association include the chronic pro-inflammatory state, the excessive oxidative stress response, and the impaired immunity that is commonly reported in these individuals. The role of cytokines, mammalian target of rapamycin (mTOR), and altered natural killer cell polarization in the dangerous liaison between COVID-19 and obesity are discussed here. These pathways can favor and accelerate the deleterious downstream cellular effects of SARS-CoV-2. Moreover, obesity is well known to be associated with reduced lung function and poor response to mechanical ventilation, thus placing these individuals at high risk of severe illness and mortality from COVID-19. Furthermore, obesity may lead to other complications, such as renal failure, cardiovascular dysfunction, hypertension, and vascular damage, which in turn can further accelerate negative clinical outcomes from COVID-19. Obese individuals should be shielded against any potential viral exposure to SARS-CoV-2 with consequential considerations for compulsory protection devices and social distancing. Health care providers should be aware that obesity predisposes to severe symptoms and negative prognosis in COVID-19 patients.