Obesity & Viral Consequences: New Study Reveals Impact
Table of Contents
Obesity and metabolic diseases have long been recognized as significant risk factors for severe COVID-19. Though, emerging research suggests that SARS-CoV-2 infection itself can also trigger the onset of new metabolic problems, even in individuals who are not overweight.
A groundbreaking study, published in PLOS Pathogens, investigated the long-term effects of the SARS-CoV-2 delta variant in adult male rhesus macaques. The research team meticulously tracked both lean and obese, insulin-resistant animals over a six-month period following infection. The findings reveal a complex picture of persistent physiological changes, indicating that long COVID may be more prevalent than previously understood, particularly in its subtler, metabolic manifestations.
Metabolic Shifts: A Tale of Two Bodies
While the initial viral load in the respiratory system, antibody responses, and inflammatory markers were largely comparable between lean and obese macaques, the long-term consequences diverged significantly based on metabolic status.
Lean Monkeys Face Metabolic Disruption
intriguingly, lean animals in the study were more susceptible to developing signs of metabolic disruption. A key finding was a substantial decrease in the ratio of adiponectin to leptin in lean macaques. Adiponectin and leptin are crucial hormones that regulate metabolism and appetite. A lower adiponectin-to-leptin ratio is a recognized indicator of poorer metabolic health,and in this study,lean animals saw this marker decline to levels previously observed only in their obese counterparts.
“Some parameters changed more robustly in obese animals, while others changed more robustly in lean animals,” the authors stated. “Thus, persistent effects of SARS-CoV-2 infection are both obesity-dependent and self-reliant.”
obesity’s Persistent Risks
Obese macaques, while not exhibiting the same degree of metabolic disruption as the lean group, faced other significant long-term challenges. These included a higher likelihood of persistent lung damage and prolonged weight loss following the initial infection.
The Silent Symptoms of Long COVID
The study’s findings underscore a critical point: many long-term effects of COVID-19 are physiological rather than overtly symptomatic. this suggests that the true burden of long COVID could be significantly underestimated by self-report data alone.
“I think one of the most striking results of our study was the extent of long-term adverse effects seen after a what outwardly appeared to be a very mild initial disease course,” commented Charles Roberts, Professor at Oregon Health & Science University and a lead author on the study. “This suggests that long COVID can indeed result from a mild infection.”
Dr. roberts further elaborated, “Since we saw increased levels of inflammatory factors and changes in biomarkers of cardiometabolic disease risk 6 months after infection, some symptoms of long COVID may only become apparent long after the initial infection.”
A Model for Future Research
The development of this macaque model of long COVID offers a powerful tool for future research. Coauthor Dr. Kristin Sauter highlighted the potential for comparing the effects of different SARS-CoV-2 variants. “Our development of a macaque model of long COVID will allow us to directly compare the intrinsic differences between the effects of the delta variant described in this study with the effects of later variants such as omicron, which is the subject of our current NIH-supported work,” she noted.
This comparative approach is invaluable because the macaques used in these studies have no prior exposure to SARS-CoV-2. This allows researchers to attribute any observed differences in response directly to the specific variants, circumventing the complexities of pre-existing immunity that often complicate human studies.
The research provides crucial insights into the multifaceted and often hidden long-term consequences of SARS-CoV-2 infection, emphasizing the need for continued investigation into the metabolic health of individuals recovering from COVID-19, irrespective of their initial weight or the severity of their acute illness.
Source: Jump, K. A., et al.(2025).Effect of obesity on the acute response to SARS-cov-2 infection and development of post-acute sequelae of COVID-19 (PASC) in nonhuman primates. PLOS Pathogens*. doi.org/10.1371/journal.ppat.1012988