New Study Links Prior Obesity to Long-Term SARS-CoV-2 Effects

A recent study has revealed that prior obesity significantly influences the long-term consequences of SARS-CoV-2 infection. Conducted by researchers at Oregon Health & Science University, the study highlights how the metabolic status of primates can alter their response to the virus, particularly in terms of what is termed long COVID or post-acute sequelae of COVID-19 (PASC). The findings were published on July 24, 2023, in the open-access journal PLOS Pathogens.

The research focused on adult male rhesus macaques, comparing the effects of the SARS-CoV-2 delta variant on both lean and obese animals. The study spanned a six-month period, during which the researchers observed significant differences in the long-term impacts of the infection based on the metabolic health of the subjects. While many parameters, such as viral load in the respiratory system and levels of inflammatory factors, remained similar across both groups, the long-term effects diverged markedly.

Animals with obesity faced heightened risks, including persistent lung damage and prolonged weight loss. In contrast, lean macaques exhibited signs of metabolic disruption, including a significant decrease in the ratio of adiponectin to leptin, hormones critical for metabolic health. As a result, their metabolic health markers dropped to levels comparable to those of their obese counterparts.

The study suggests that the prevalence of long COVID may be more widespread than what human self-reports typically indicate. “Some parameters changed more robustly in obese animals, while others changed more robustly in lean animals,” the authors noted. “Thus, persistent effects of SARS-CoV-2 infection are both obesity-dependent and independent.”

Professor Charles Roberts, a leading researcher in the study, emphasized the implications of their findings: “One of the most striking results was the extent of long-term adverse effects seen after what appeared to be a very mild initial disease course. This suggests that long COVID can indeed result from a mild infection.”

Dr. Kristin Sauter, a co-author of the study, added that their development of a macaque model for long COVID would facilitate direct comparisons between the effects of the delta variant and later variants, such as omicron. This approach is particularly valuable, as the macaques used in the research had no prior exposure to SARS-CoV-2, allowing researchers to attribute any differing responses directly to the variants rather than to pre-existing immunity.

The findings from this study underscore the urgent need for further research into the long-term consequences of COVID-19, especially regarding how prior metabolic conditions like obesity can shape outcomes following infection. As the global health community continues to grapple with the ramifications of the pandemic, understanding the nuanced effects of the virus on different populations remains crucial.