geoffrey modest medical blogs

  a recent large Canadian study confirmed that there were very few false positive results in rapid antigen tests for SARS-CoV-2 virus, and that the limited number of false positives were largely from manufacturing issues of the tests (see  covid false pos rapid antigen rare JAMA2022 in dropbox, or doi:10.1001/jama.2021.24355)   Details: -- Canada implemented their Creative Destruction Lab Rapid Screening Consortium (CDL RSC) in order to help protect against Covid transmission in workplaces     -- this program was set up to inform the operational requirements of rapid antigen screening in workplaces -- asymptomatic employees were screened twice weekly, on a voluntary basis -- data collected from January 11 to October 13, 2021 during which there were two significant Delta variant waves (March to June and August to October) -- screening results were recorded, including the place of employment, the test done, and (optionally) the lot number of the...

  The first study was just reported on viral kinetics and other outcomes in volunteers inoculated with SARS-CoV-2 virus (see  covid human challenge UK NatMed2022  in dropbox, or  doi.org/10.1038/s41591-022-01780-9 ) Details: --36 volunteers aged 18 to 29, without evidence of prior infection or vaccination, were inoculated with 10TCID 50  of pre-alpha wild type (i.e. the original) of  SARS-CoV-2 intranasally, in an open-label nonrandomized study     --  TCID 50  is the Median Tissue Culture Infectious Dose; and, 10 TCID 50  is a low starting  inoculum dose -- these individuals had none of the following risk factors for severe covid: low  or high BMI; abnormal labs including CBC, renal or liver function, clotting, or viral serology to exclude other viruses; spirometry; echocardiography; chest x-ray -- mean age 22, 75% male, 92% white, BMI 23 -- after inoculation, the volunteers were  housed in a high-containment quarant...