A higher BMI related to an increased risk of SARS-CoV-2 infection

Coronavirus 2019 disease (COVID-19), caused by severe acute respiratory coronavirus syndrome (SARS-CoV-2), causes serious illness in high-risk populations. These include the elderly and those with underlying diseases such as diabetes, hypertension, heart disease and obesity.

Researchers at Miller University School of Medicine in the University of Miami, USA, revealed that spike-specific immunoglobulin G antibodies in obese people are negatively associated with body mass index (BMI) and serum levels of proinflammatory and metabolic markers of lung inflammation.

The study, published in the preprinted journal medRxiv *, it was also found that a higher BMI is related to a higher rate of SARS-CoV-2 infection.

Obesity and COVID-19

SARS-CoV-2 is actively spreading worldwide. It has infected more than 78 million people and killed more than 1.71 million. Information on human immune responses to SARS-CoV-2 infection is limited.

However, recent studies have shown that some people are more likely to become infected and develop a more serious illness than others. Older adults and those with comorbidities are more likely to develop severe COVID-19. Recently, studies have also shown that obesity can predispose a person to severe COVID-19.

Recently published data showed that chronic low-grade systemic inflammation, called inflammation, is the leading cause of cellular and molecular changes induced by SARS-CoV-2. It is also responsible for higher mortality rates.

Persistent obesity-induced local and systemic inflammation contributed to impaired immune cells and reduced immunity.

Inflammation found in obese individuals leads to several debilitating chronic diseases, such as cancer, atherosclerosis, type 2 diabetes, and inflammatory bowel disease. Obesity is an additional risk factor for severe COVID-19.

The study

To reach the study’s findings, the researchers evaluated the effects of obesity on the secretion of SARS-CoV-2-specific IgG antibodies in the blood of patients with COVID-19.

The team measured serum levels of SARS-CoV-2-specific IgG antibodies in lean and obese patients with COVID-19, as well as in uninfected controls, using an enzyme-linked immunosorbent assay (ELISA).

First, the study found that BMI was higher in patients with SARS-CoV-2 positive compared to uninfected controls. This suggests that a higher BMI is associated with severe respiratory symptoms. During hospitalization, those with a higher BMI present with severe respiratory symptoms such as cough, fever, shortness of breath, and hypoxia or low oxygen levels.

The results of the study also showed that spike-specific IgG antibodies in obese people are negatively related to BMI and serum levels of proinflammatory and metabolic markers of inflammation and lung inflammation.

The data collected could help develop an inflammatory signature with a strong predictive value of immune dysfunction, which can be used as a therapeutic target to enhance humoral immunity among obese people.

Another result of the present study is the negative association of SARS-CoV-2 IgG antibodies with markers of lung inflammation (SAA, CRP, ferritin) in our cohort of COVID-19 patients, ”the researchers explained.

“These are the major inflammatory mediators and markers of inflammatory lung injury in patients with catastrophic acute respiratory disorder syndrome, which is a major consequence of COVID-19,” they added.

The results of the research support that influenza-like SARS-CoV-2 infection may induce degradation of self-tolerance to autoantigens in obese people. It is essential to consider them as a high-risk group, most likely to develop severe symptoms due to COVID-19.

In addition, the quality of the antibody response in obese patients with COVID-19 is crucial for future vaccination efforts to prevent SARS-CoV-2 infection and the complications associated with COVID-19. Obese people can also benefit if they are among the first to receive a vaccine.

* Important news

medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information.