Viral Load and COVID-19

Few studies have examined the association between upper respiratory tract (URT) viral load and symptomatic COVID-19 disease severity .  This study, however, examined URT viral load of patients with symptomatic or asymptomatic COVID-19 infection and their association with various host factors such as age, gender, comorbidities, disease severity and outcome.  The study included 1,122 patients and 274 (24.4%) had an asymptomatic infection.  Approximately 309 patients (27.5%) had a high URT viral load, 316 (28.2%) moderate, and 497 (44.3%) low URT viral load.  Those with a high URT viral load had at least one comorbidity compared to patients with moderate or low URT viral load (40.1% compared to 32.9% and 21.7%, respectively; p-value < 0.001).  Comorbidities that were associated with a high URT viral load were: cardiovascular disease, hypertension, chronic pulmonary disease, immunosuppression, obesity, and chronic neurological disease (p-value <0.05 for all comparisons).  High URT viral load was also associated with higher rates of COVID-19 infection, intubation and mortality compared to patients with moderate or low URT viral load (p-values< 0.001, 0.05, and 0.03 respectively).  Contrarily, patients with an asymptomatic infection were more likely to have a low URT viral load (p-value <0.001).

Obesity and COVID-19

 Obesity is a strong risk factor for COVID-19.  But why does obesity cause vulnerability to infectious diseases like COVID-19?  This study explored how the obese host provides a unique and favorable environment for disease pathogenesis which leads to complications of the disease and adverse outcomes.  The articles states that those who are obese typically have elevated fatty acids and may experience cell hypertrophy, hypoxia, and/or mitochondrial dysfunction.  This in turn leads to an increase in M1 macrophages, B-cells, and mast cells which encourages inflammation while M2 Macrophages, T cells, and Th2 cells are decreased which help to direct a proper immune response.  As a result, the obese experience chronic inflammation and with the cellular immune function being impaired, they experience worse outcomes related to infectious diseases such as COVID-19.  Obesity may also lead to systemic insulin resistance which may negatively impact immune function.

Another study evaluated inflammatory markers in obese and non-obese individuals hospitalized for COVID-19.  There were 781 patients of which 349 (45%) were obese.  The results indicated that obese individuals had higher initial and peak CRP and ESR levels and a higher peak d-dimer (p < 0.01 for all) in comparison to those who were not obese.  Furthermore, those who were obese were more likely to require vasopressor use (OR 1.54, 95% CI 1.00-2.38, p = 0.05), develop hypoxemic respiratory failure (OR 1.58, 95% CI 1.04-2.40, P = 0.03) and experience mortality (OR 2.20, 95% CI 1.31-3.70, P = 0.003) within 28 days of clinical care presentation.  Lastly, those who were obese had worse clinical outcomes compared to their counterparts largely due to increased inflammation.

Interestingly, this article discussed Self-Determination Theory (SDT), Transtheoretical Model (TTM), Motivational Interviewing (MI) and Mindfulness which are theories and approaches that can be utilized in the clinical setting to virtually assist those who are obese.  These theories and approaches are all inter-related and have been shown to promote long-term behavioral change.  For example, mindfulness has been shown to be effective in weight reduction and improving obesity-related eating behaviors, including emotional, impulsive and binge eating .  The author describes a study where one group of subjects was given soup in special bowls which, unknown to them, self-refilled as their contents were consumed while the second group was given soup in normal bowls.  Those in the first group ate 73% more than the second group but they did not believe they had consumed more.  This illustrates the importance of mindfulness.  With COVID-19, telehealth and telemedicine are being utilized more to increase access to care.  The author states that MI provided through the telephone is effective for weight loss and text messaging may be a promising option.