Weekly Clinical Updates

Incidence, co-occurrence, and evolution of long-COVID features: A 6-month retrospective cohort study of 273,618 survivors of COVID-19 | Safety Monitoring of an Additional Dose of COVID-19 Vaccine — United States, August 12–September 19, 2021 | Impact of Timing of Tocilizumab Use in Hospitalized Patients With SARS-CoV-2 Infection

Virologic features of SARS-CoV-2 infection in children | Steroids use in non-oxygen requiring COVID-19 patients: a systematic review and meta-analysis | NIH builds large nationwide study population of tens of thousands to support research on long-term effects of COVID-19 The COVID-19 Hospitalization Metric in the Pre- and Post-vaccination Eras as a Measure of Pandemic Severity: A Retrospective, Nationwide Cohort Study | High genetic barrier to escape from human polyclonal SARS-CoV-2 neutralizing antibodies | Considerations in boosting COVID-19 vaccine immune responses | HHS Announces State/territory-coordinated Distribution System for Monoclonal Antibody Therapeutics | Daily testing for contacts of individuals with SARS-CoV-2 infection and attendance and SARS-CoV-2 transmission in English secondary schools and colleges: an open-label, cluster-randomised trial | SARS-CoV-2 Transmission to Masked and Unmasked Close Contacts of University Students with COVID-19 — St. Louis, Missouri, January–May 2021 | A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

Long-Term Symptoms Among Adults Tested for SARS-CoV-2 — United States, January 2020–April 2021 | Overlooked Shortcomings of Observational Studies of Interventions in Coronavirus Disease 2019: An Illustrated Review for the Clinician | Long-Term Symptoms Among Adults Tested for SARS-CoV-2

Ivermectin Intended for Animals: Letter to Stakeholders - Do Not Use in Humans as a Treatment for COVID-19 | Characteristics and Outcomes of Women With COVID-19 Giving Birth at US Academic Centers During the COVID-19 Pandemic | Children and COVID-19: State-Level Data Report | Long COVID - the physical and mental health of children and non-hospitalised young people 3 months after SARS-CoV-2 infection; a national matched cohort study (The CLoCk) Study. | Outbreak Associated with SARS-CoV-2 B.1.617.2 (Delta) Variant in an Elementary School — Marin County, California, May–June 2021 | 1-year outcomes in hospital survivors with COVID-19: a longitudinal cohort study | Convalescent plasma recommendations from IDSA

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.