Glucose control during breakthrough SARS-CoV-2 infections in vaccinated patients with type 1 diabetes

Aims This study aims at evaluating the trend of glycemic control metrics during the infection of SARS-CoV-2 in individuals with Type 1 Diabetes (T1D) using a Continuous Glucose Monitoring (CGM) system and vaccinated against COVID-19.Materials and methods This is a retrospective study of T1D subjects who got a breakthrough SARS-CoV-2 infection between November 2021 and February 2022. Data of glycemic control of CGM-derived metrics were compared 14 days before COVID-19 (Time 1), 14 days during COVID-19 (Time 2) and 14 days after COVID-19 (Time 3).Results A total of 106 patients with T1D and breakthrough SARS-CoV-2 infection was included in the analysis. A significant reduction of GMI [%, 7.41 +/- 1.60 vs 7.52 +/- 1.63, P = 0.006)] and increase of TIR [%, 54.6 +/- 20.4 vs 52.1 +/- 19.7, P = 0.026] were observed at Time 3 as compared with Time 2. There was a significant reduction of SD (P < 0.001) and CV (P < 0.001) at Time 3 and Time 2 as compared with Time 1, associated with significant changes of mean glucose levels, TBR level 1 and total daily insulin doses.Conclusions Breakthrough SARS-CoV-2 infection did not worsen glycemic control in vaccinated people with T1D.