Obesity Differs from Diabetes Mellitus in Antibody and T Cell Responses Post COVID-19 Recovery

ObjectiveObesity 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. MethodsIn 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. ResultsIn 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-{gamma} 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. ConclusionsObesity 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?O_LIThe impact of obesity and diabetes mellitus (DM) on COVID-19 severity and mortality is disproportionately high in South Asian populations. C_LIO_LIPeople with obesity and DM experience reduced protection against COVID-19 after vaccination. C_LI What are the new findings in your manuscript?O_LIDespite 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. C_LIO_LIAntigen-specific antibody and T cell responses are preserved in individuals with DM who survive SARS-CoV-2 infection. C_LI How might your results change the direction of research or the focus of clinical practice?O_LIOur 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. C_LIO_LIOur 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. C_LI