April 30 | Weekly COVID-19 LST Report

Understanding the Pathology

· IL-33 expression in response to SARS-CoV-2 correlates with seropositivity in COVID-19 convalescent individuals: Immunologists from the Max Planck Institute in Germany and Bloomberg-Kimmel Institute in the United States evaluated immune responses to SARS-CoV-2 in 155 individuals with professional exposure and found anti-Spike IgG/IgM titers remain elevated 60 days post-infection and the only clinical symptom associated with high titers was fever. Additionally, they found that SARS-CoV-2 peptide stimulation of peripheral blood monocytes from seropositive individuals stimulates interleukin-33 (IL-33) production which was associated with CD4 T-cell activation. Because IL-33 is known to be involved in the pathophysiology of asthma and COPD, the authors suggest more research to better understand the role of IL-33 in the pathogenesis of COVID-19.

Transmission & Prevention

· Age- and gender-dependent antibody responses against SARS-CoV-2 in health workers and octogenarians after vaccination with the BNT162b2 mRNA vaccine: Cell biologists and clinical biochemists from the University of Athens evaluated SARS-CoV-2 antibody responses in 255 health workers from Alexandra General Hospital in Athens, Greece (group 1) and 112 octogenarians (group 2) after receiving BNT162b2 mRNA vaccination. They found Anti-Spike-RBD IgG antibodies and NAbs against SARS-CoV-2 increased after vaccination before plateauing two weeks after the second dose, with a more robust response in younger individuals compared to the older cohort and female octogenarians compared to male. The authors suggest humoral responses to the BNT162b2 mRNA vaccine are age and gender dependent and that administration of a timely second vaccine is critical to maximizing the immune response.

· Open Schools, Covid-19, and Child and Teacher Morbidity in Sweden: Swedish pediatricians used a nationwide intensive care registry to study SARS-CoV-2 infections among children and teachers between March 1 and June 30, 2020, where schools remained opened and masking was not mandatory. Fifteen children with COVID-19 were admitted to an ICU (0.77 per 100,000 children), four of whom had an underlying chronic coexisting condition; none died. Fewer than 10 preschool teachers and 20/103,596 schoolteachers in Sweden received intensive care for COVID-19 (age-adjusted relative risk 1.10 [95%CI 0.49-2.49] for preschool teachers and 0.43 [95% CI 0.28-0.68] for schoolteachers). Authors suggest SARS-CoV-2 transmission in school settings is low, though acknowledge lack of data about household transmission and wide confidence intervals.

R&D: Diagnosis & Treatments

· Are sniffer dogs a reliable approach for diagnosing SARS-CoV-2 infection?: A biochemist, public health expert, and pediatric intensivist from the University of Verona and Cincinnati Children's Hospital performed a critical review and pooled analysis of three studies analyzing the efficacy of dogs trained to identify patients infected with SARS-CoV-2. In 17 dogs, the diagnostic sensitivity was 0.88 (95% CI, 0.84–0.91; I2, 85.3%) - above that of tested nasopharyngeal swab samples seen in some other studies - and specificity was 0.99 (95% CI, 0.99–0.99; I2, 97.4%). Due to the time needed to train the dogs, the dependency on the state of the dog, and potentially confounding odors from comorbidities, authors suggest the use of dogs should be further investigated at a larger scale to better determine its practical applications for SARS-CoV-2 testing.

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