geoffrey modest medical blogs

  after having just sent out the blog on daycare and alluding to a prior one on schools, the MMWR just released another study finding some (see   https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e4.htm?s_cid=mm7008e4_x ) in very brief: -- 9 covid transmission clusters in Ge ​ orgia elementary schools involving 13 educators and 32 students, from Dec1 to Jan 20 --in 1 cluster, the index person was a student, in 4 it was the teacher (these were clusters where there was a known index person) -- but:      --plastic dividers were in place between students, but the students were <3 ft apart; the room set-ups did not allow the 6-foot distancing     --in some cases, there were small group sessions with increased proximity between educators and students     --though mask-wearing was apparently pretty consistent, interviews suggested that there were specific instances of lack of or inadequate student mask use     --when eating, masks were not r...

  The MMWR just released a case report suggesting the inadequacy of their prior advisory to avoid exposures of distancing less than 6 feet for more than 15 minutes (see   https://www.cdc.gov/mmwr/volumes/69/wr/mm6943e1.htm?s_cid=mm6943e1_w   )   Details: -- a 20-year-old male correctional officer in Vermont was found to have symptomatic Covid-19 on August 11 -- on July 28, he had multiple brief encounters with 6 incarcerated or detained persons (IDPs) who were asymptomatic but in the process of having PCR-based SARS-CoV-2 testing; these 6 people arrived from out-of-state correctional facility on July 28 and were housed in a quarantine unit -- on July 29, all 6 IDPs tested positive for SARS-CoV-2 -- contact tracing was done by the Vermont Department of Health and the Vermont Department of Corrections, finding that this correctional officer did not meet the Department of Health definition of close contact (within 6 feet of infected person for more than 15 consecut...

  There is continuing discussion on appropriate social distancing, with recent arguments that in schools it is fine to reduce the distancing from 6 feet to 3 feet. However, the guidelines on appropriate social distancing are not based on much evidence. In this light, a review of the existing studies   suggests that the even the 6 foot distance may well be inadequate (see  covid droplet distance greater than 6 feet JID2020  in dropbox, or DOI: 10.1093/infdis/jiaa189)    Details: --a systematic review assessed the horizontal distance traveled by respiratory droplets --this reviewed included 10 studies from both the medical and science/engineering journals   Results: --these studies used differing methodologies in determining the spread of virus, with 7 of the 10 using modeling --5 of the studies did experiments on human subjects, 4 of which did not use any artificial fluids or powders to induce sneezes or coughs. --8 of the 10 studies found that droplets...