Higher BMI linked to increased risk of SARS-CoV-2 infection

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

Researchers at the University of Miami Miller School of Medicine, USA, revealed that the 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 pulmonary inflammation.

The study, published in the pre-print journal medRxiv*, also found that higher BMI is tied to a higher infection rate with SARS-CoV-2.

Obesity and COVID-19

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

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

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

Obesity-induced persistent local and systemic inflammation contributed to the impairment of immune cells and reduced immunity.

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

The study

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

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

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

The study findings also showed that spike-specific IgG antibodies in obese people are negatively linked to BMI and serum levels of proinflammatory and metabolic markers of inflammaging and pulmonary inflammation.

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

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

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

The research findings support that SARS-CoV-2 infection, akin to influenza, may induce self-tolerance breakdown to autoantigens in obese people. It is essential to consider them as a high-risk group, who are more likely to develop severe symptoms due to COVID-19.

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

*Important Notice

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

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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  1. Paul Wolf Paul Wolf United States says:

    The best defense against covid and all the problems associated with obesity is to keep exercise as one of the highest priorities of your day.  When I'm in good physical shape, I'm in much better health overall.

  2. Mazhar Qaiyum Mazhar Qaiyum India says:

    Thanks a lot. Systemic inflammation in obesity is probably also the reason why type 2 DM affects obese people more so than others.

  3. Mazhar Qaiyum Mazhar Qaiyum India says:

    I wanted a channel through which I could procure medical news and articles.
    Here you have pointed out that obese people are affected more so than others because of systemic inflammation. Systemic inflammation is also the reason why obese people suffer from TYPE 2 DM more so than others.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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