Obesity Differs from Diabetes Mellitus in Antibody and T Cell Responses Post COVID-19 Recovery
Authors: Ali Mohammad , Longet Stephanie , Neale Isabel , Rongkard Patpong , Chowdhury Forhad Uddin Hassan , Hill Jennifer , Brown Anthony , Laidlaw Stephen , Tipton Tom , Hoque Ashraful , Hassan Nazia , Hackstein Carl-Philipp , Adele Sandra , Akther Hossain Delowar , Abraham Priyanka , Paul Shrebash , Rahman Md Matiur , Alam Md Masum , Parvin Shamima , Mollah Forhadul Hoque , Hoque Md Mozammel , Moore Shona C , Biswas Subrata K , Turtle Lance , de Silva Thushan I , Ogbe Ane , Frater John , Barnes Eleanor , Tomic Adriana , Carroll Miles W , Klenerman Paul , Kronsteiner Barbara , Chowdhury Fazle Rabbi , Dunachie Susanna J 
Published: June 2023

Objective

Obesity and type 2 diabetes (DM) are risk factors for severe COVID-19 outcomes, which disproportionately affect South Asian populations. This study aims to investigate the humoral and cellular immune responses to SARS-CoV-2 in adult COVID-19 survivors with obesity and DM in Bangladesh.

Methods

In this cross-sectional study, SARS-CoV-2-specific antibody and T cell responses were investigated in 63 healthy and 75 PCR-confirmed COVID-19 recovered individuals in Bangladesh, during the pre-vaccination first wave of the COVID-19 pandemic in 2020.

Results

In COVID-19 survivors, SARS-CoV-2 infection induced robust antibody and T cell responses, which correlated with disease severity. After adjusting for age, sex, DM status, disease severity, and time since onset of symptoms, obesity was associated with decreased neutralising antibody titers, and increased SARS-CoV-2 spike-specific IFN-γ response along with increased proliferation and IL-2 production by CD8+ T cells. In contrast, DM was not associated with SARS-CoV-2-specific antibody and T cell responses after adjustment for obesity and other confounders.

Conclusions

Obesity is associated with lower neutralising antibody levels and higher T cell responses to SARS-CoV-2 post COVID-19 recovery, while antibody or T cell responses remain unaltered in DM.

Study Importance

What is already known about this subject?

The impact of obesity and diabetes mellitus (DM) on COVID-19 severity and mortality is disproportionately high in South Asian populations.

People with obesity and DM experience reduced protection against COVID-19 after vaccination.

What are the new findings in your manuscript?

Despite similar IgG antibody levels, adults with overweight/obesity (BMI ≥ 23 kg/m2) have lower neutralising antibody capacity and higher T cell responses to SARS-CoV-2 following COVID-19 recovery.

Antigen-specific antibody and T cell responses are preserved in individuals with DM who survive SARS-CoV-2 infection.

How might your results change the direction of research or the focus of clinical practice?

Our findings underscore the critical need to understand the mechanisms underlying the diminished neutralising capacity of antibodies in obesity, as this has profound implications for the development of effective interventions and treatments for COVID-19.

Our study highlights the significance of T cells in COVID-19 survivors with obesity, indicating their potential role in informing the development of next-generation vaccines against coronaviruses.