SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion

Abstract: The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era

Safety and efficacy of initial trocar placement in morbidly obese patients

Hypothesis: The use of a nonbladed trocar with an optical view is a safe and effective method for initial trocar placement for laparoscopic bariatric surgery. Design Retrospective review of consecutive patients. Setting University-associated hospital. Patients All patients who underwent laparoscopic bariatric surgery from December 2002 to November 2003. Intervention Initial trocar placement. Main Outcome Measures Injury and bleeding during initial trocar placement, trocar placement time, and insufflation time. Trocar placement time was defined as the time to place the trocar into the peritoneal cavity (including infiltration of local anesthesia and incision). Insufflation time was defined as time to insufflate the abdomen to a pressure of 10 to 15 mm Hg (including time to place tubing on trocar). Results: There were 228 patients who had no evidence of any bowel or vessel injury during initial trocar placement. In the last 50 patients, average body mass index (calculated as weight in kilograms divided by the square of height in meters) was 47 (range, 35-63). Average trocar placement time was 25 seconds (range, 10-60 seconds), and average insufflation time was 16 seconds (range, 5-25 seconds). In almost all cases, appropriate pneumoperitoneum was established in less than a minute. No correlation was seen between times and body mass index (trocar, P =3D .56; insufflation, P =3D .95) or waist-hip circumference (trocar, P =3D .74; insufflation, P=3D.48). Conclusions: Initial trocar placement using a nonbladed trocar with an optical view without prior abdominal insufflation is safe and effective in morbidly obese patients. This method can be applied even in the super obese