Fig. 6. Age and obesity as risk factors for severity associated with MA-SARS-CoV-2.

A Six- to eight-week-old C57Bl6 mice were fed with sucrose-matched high fat (n = 30) or control diet (n = 30) for up to 14 weeks and body weight changes were recorded. B Mice on control or high-fat diet were fasted for 6 h followed by an intraperitoneal injection of dextrose solution at 2 g/kg body weight. Blood was drawn at different time points by submandibular bleed and blood glucose levels were determined by Glucose assay. C Diagrammatic representation of intranasal infection with 1.7 × 10³ PFU/mouse of SARS-CoV-2 variant (MA-SARS-CoV-2) followed by harvest of various organs to assess virus replication. D, E the body weight changes were monitored post-infection until the harvest (n = 4–5). Higher lung virus titers were observed in obese mice (D-i) accompanied with noticeable loss in body weight (D-ii) as compared to lean/control diet mice. Similarly, the lung virus titers (right lung lobes) (E-i) and body weight loss (E-ii) were found to be higher in 52-week-old mice as compared to 6–8-weeks young/control mice, 5 days post-infection. No virus titers were found in other organs harvested 5 days post-infection in both experiments. Two-sided Mann–Whitney U test was performed to calculate the statistical significance between different groups. Symbols represent geometric means; error bars represent standard deviation. Each data point corresponds to individual mouse and the number of data points represents the number of mice in the corresponding groups. Source data are provided as a Source Data file.