Direct comparison of RT-ddPCR and targeted amplicon sequencing for SARS-CoV-2 mutation monitoring in wastewater.

Over the course of the COVID-19 pandemic, variants of SARS-CoV-2 have emerged that are more contagious and more likely to cause breakthrough infections. Targeted amplicon sequencing approach is a gold standard for identification and analysis of variants. However, when applied to environmental samples such as wastewater, it remains unclear how sensitive this method is for detecting variant-associated mutations in environmental samples. Here we directly compare a targeted amplicon sequencing approach (using ARTIC v3; hereafter referred to as sequencing) with RT-ddPCR quantification for the detection of five mutations that are characteristic of variants of concern (VoCs) in wastewater samples. In total, 547 wastewater samples were analyzed using both methods in parallel. When we observed positive mutation detections by RT-ddPCR, 42.6% of the detection events were missed by sequencing, due to negative detection or the limited read coverage at the mutation position. Further, when sequencing reported negative or depth-limited mutation detections, 26.7% of those events were instead positive detections by RT-ddPCR, highlighting the relatively poor sensitivity of sequencing. No or weak associations were observed between quantitative measurements of target mutations determined by RT-ddPCR and sequencing. These findings caution the use of quantitative measurements of SARS-CoV-2 variants in wastewater samples determined solely based on sequencing.

A 6-month, office-based, low-carbohydrate diet intervention in obese teens.

BACKGROUND: Previous studies have shown the success of a low-carbohydrate diet (LCD) in adults. In one study, the LCD has also been shown as safe and effective in teens, the study period was only 12 weeks. Furthermore, there is no information on whether the LCD is a practical intervention in a pediatric office setting. OBJECTIVE: The object of this study was to demonstrate the effectiveness of a LCD in obese children in a primary care pediatric setting. DESIGN/METHODS: The study was done in 11 community pediatric practices. Children ages 12 to 18 years with a body mass index (BMI) greater than 95th percentile were put on a LCD of less than 50 grams of carbohydrate daily. RESULTS: A total of 38 of the 63 teens finished the 6-month study and 32 (84%) lost weight (range from a gain of 5.5 kg to a loss of 23.9 kg). There was also a significant decrease in mean BMI (34.9 to 32.5). CONCLUSIONS: The LCD appears to an effective and practical office-based intervention in obese teenagers.