Weekly Clinical Updates

Unvaccinated COVID-19 hospitalizations cost the U.S. health system billions of dollars | Comirnaty and PfizeSARS-CoV-2 Infections and Hospitalizations Among Persons Aged ≥16 Years | A third COVID-19 vaccine shot markedly boosts neutralizing antibody potency and breadth | Durability of antibody responses elicited by a single dose of Ad26.COV2.S and substantial increase following late boosting |.Virological characteristics of SARS-CoV-2 vaccine breakthrough infections in health care workers | COVID-19 Transmission Dynamics Among Close Contacts of Index Patients With COVID-19 | COVID-19 false dichotomies and a comprehensive review of the evidence regarding public health, COVID-19 symptomatology, SARS-CoV-2 transmission, mask wearing, and reinfection

The SARS-CoV-2 Delta variant and its sublineages (B.1.617.2, AY.1, AY.2, AY.3; [1]) can cause high viral loads, are highly transmissible, and contain mutations that confer partial immune escape [2,3]. Using PCR threshold cycle (Ct) data from a single large contract laboratory, authors show that individuals in Wisconsin, USA had similar viral RNA loads in nasal swabs, irrespective of vaccine status, during a time of high and increasing prevalence of the Delta variant. Infectious SARS-CoV-2 was isolated from 51 of 55 specimens (93%) with Ct <25 from both vaccinated and unvaccinated persons, indicating that most individuals with Ct values in this range (Wilson 95% CI 83%-97%) shed infectious virus regardless of vaccine status. Notably, 68% of individuals infected despite vaccination tested positive with Ct <25, including at least 8 who were asymptomatic at the time of testing.

An Examination of School Reopening Strategies during the SARS-CoV-2 Pandemic | Effect of Convalescent Plasma on Mortality among Hospitalized Patients with COVID-19: Initial Three-Month Experience | Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Kenyan blood donors

An Examination of School Reopening Strategies during the SARS-CoV-2 Pandemic | Effect of Convalescent Plasma on Mortality among Hospitalized Patients with COVID-19: Initial Three-Month Experience | Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Kenyan blood donors

SARS-CoV-2 Infection in Public School District Employees Following a District-Wide Vaccination Program — Philadelphia County, Pennsylvania, March 21–April 23, 2021 | More kids are being hospitalized for COVID, due to fewer masks, stagnating vaccination rates | Updated masking guidance from CDC

An Examination of School Reopening Strategies during the SARS-CoV-2 Pandemic | Effect of Convalescent Plasma on Mortality among Hospitalized Patients with COVID-19: Initial Three-Month Experience | Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Kenyan blood donors