Obesity-Related Outcomes in COVID-19 Patients

Obesity has emerged as a major determinant of adverse outcomes in COVID-19, with excess adiposity influencing both susceptibility to infection and the severity of clinical courses. Individuals with raised body mass index (BMI) exhibit a heightened risk of hospitalisation, intensive care unit (ICU) admission and mortality compared with those in a healthy weight range. Mechanisms underlying these associations include chronic low-grade inflammation, dysregulated immune responses, altered pulmonary mechanics and impaired vaccine-induced immunity. Globally, the convergence of rising obesity prevalence and recurrent waves of SARS-CoV-2 infection has strained health-care resources and challenged vaccination strategies. Understanding how obesity modulates antiviral defences and resource utilisation is essential for tailored prevention, booster scheduling and therapeutic prioritisation in higher-risk populations.

Research from Nature Portfolio

Recent studies have shown that vaccine-induced humoral immunity wanes more rapidly in individuals with severe obesity. Following two doses of mRNA vaccine, people with a BMI above 40 kg/m2 exhibited lower titres of neutralising antibody against authentic SARS-CoV-2 and a steeper decline over six months compared with controls in the healthy weight range. A third dose restored neutralising capacity but did not fully normalise the accelerated waning, highlighting the need for refined booster protocols in this group.

Investigations into pulmonary host responses have revealed that obesity impairs type I interferon production in airway macrophages. Elevated airway leptin concentrations in people with obesity correlate inversely with ex vivo antiviral gene induction in bronchoalveolar cells. Experimental leptin administration in murine models recapitulates this defect, leading to reduced interferon-driven viral clearance. These findings identify leptin-mediated interferon suppression as a key mechanism linking excess adiposity to respiratory viral severity.

Obesity-Related Outcomes in COVID-19 Patients publication trend

The graph below shows the total number of articles in obesity-related outcomes in covid-19 patients across all publications each year (not limited to Nature Index journals).

Technical terms

Body mass index (BMI): A ratio of weight to height squared (kg/m2) used to categorise underweight, healthy weight, overweight and obesity.

Neutralising antibody: A subclass of antibodies that bind to viral surface proteins and block infection of host cells.

Adipokine leptin: A hormone produced by adipose tissue that regulates appetite and modulates immune cell function.

Type I interferon: A group of antiviral cytokines critical for early innate immune responses to viral infections.

References

1. Accelerated waning of the humoral response to COVID-19 vaccines in obesity. Nature Medicine (2023).
2. Obesity dysregulates the pulmonary antiviral immune response. Nature Communications (2023).
3. Associations between BMI and hospital resource use in patients hospitalised for COVID-19 in England: a community-based cohort study. The Lancet Diabetes & Endocrinology (2024).
4. Associations between body-mass index and COVID-19 severity in 6·9 million people in England: a prospective, community-based, cohort study. The Lancet Diabetes & Endocrinology (2021).