geoffrey modest medical blogs

  A recent systematic review documented the high proportion of patients with SARS-CoV-2 infection who are asymptomatic (see covid asymptomatic system review AIM2021 in dropbox, or doi:10.7326/M20-6976)   Details:  -- 61 studies were identified, 43 using PCR testing of nasopharyngeal swabs, 18 using antibody testing -- 14 studies had longitudinal data that reported the evolution of symptoms     --it is  very important to differentiate those truly “asymptomatic” from those who are ”presymptomatic”, since clinical  SARS-CoV-2 infections are typically asymptomatic in the beginning but those infected later develop symptoms.  “Asymptomatic” refers to people who remain without symptoms for at least 14 days   Results:  -- PCR studies:     -- 19 studies had longitudinal data on symptoms, with 14 providing information on the evolution of whether they subsequently developed symptoms     -...

Yet another article documented a high percentage of asymptomatic people with PCR-documented SARS-CoV-2 infection, this one in Maryland nursing homes/longterm care facilities (see  covid asx nursing homes jamaintmed2020 , or  doi:10.1001/jamainternmed.2020.3738 )   Details: -- universal PCR testing was done on previously untested residents in 11 Maryland long-term care facilities where prior targeted testing had been performed based on symptoms, and there were known positive Covid-19 cases      -- 9 of the sites were nursing homes, 2 were assisted living facilities      -- days between index case and testing: 3-19, mostly around 6 to 7; percent with positive tests: between 10% and 90%, overall 40% -- 2 week follow-up telephone calls in 7 of the facilities were done to get information regarding hospitalization and mortality status of all residents tested   Results: -- targeted symptom-based testing: 153 cases identified at 11 fac...

  A recent Korean study found a high rate of people with asymptomatic SARS-CoV-2 (36%), long-term PCR positivity (many over 3 weeks), and similar viral loads to those who were symptomatic (see  covid asx korea jamintmed2020  in dropbox, or doi:10.1001/jamainternmed.2020.3862) .    Details: -- 303 symptomatic and asymptomatic patients with SARS-CoV-2 infection between March 6-March 26 who had been isolated in a community treatment center in Korea because they were SARS-CoV-2 positive -- median age 25, 66% women, 4% had comorbidities (ten had hypertension, one cancer, one asthma)      -- though not statistically significant (especially given the small numbers), it may be notable that only 2 of the patients who were asymptomatic had comorbidities (whereas 10 of the symptomatic ones did) -- median time from diagnosis to isolation was 6 days -- most common symptoms in the symptomatic group were cough (56%), rhinorrhea (46%) and sputum product...

  Covid-19 outbreaks in childcare facilities in Salt Lake City suggest a potentially important role for child-to-adult transmission, even from asymptomatic or minimally symptomatic kids (see   https://www.cdc.gov/mmwr/volumes/69/wr/mm6937e3.htm   )    Details:  -- overall, there were 17 childcare facilities in Utah with at least 2 confirmed Covid cases within a 14-day period.  -- this report reflects detailed investigation and contact tracing from 3 facilities,  from April 1 to July 10   -- 184 person, including 110 children had a known epidemiologic link to one of these 3 facilities   -- 31 confirmed cases of Covid-19 occurred: 13 (42%) in children (mean age of 7, range of 0.2-16yo), 54% female  [confirmed cases had positive SARS-CoV-2 PCR test results]      -- 9 of the children had mild cases, and 4 were asymptomatic    Results:  -- transmission was documented from these children to at least 12 (...