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November 02 | Daily COVID-19 LST Report

Climate

· No-Fault Compensation for Vaccine Injury and Equitable Access to Covid-19 Vaccines are explored by Public Health experts associated with Yale University. They discuss the concept of Vaccine Nationalism, the creation of the COVAX facility, and the plight of low- and middle-income countries during the COVID-19 pandemic. To address the concerns regarding the benefits and risks of the COVID-19 vaccine as well as vaccine manufacturers protection and liability, the authors suggest utilizing a no-fault compensation for vaccine injury.

Epidemiology

· A compromised specific humoral immune response against the SARS-CoV-2 receptor-binding domain is related to viral persistence and periodic shedding in the gastrointestinal tract according to a cohort study conducted by various medical institutions in Shenzhen and Guangzhou, China. They found 21/289 Chinese patients with COVID-19 were readmitted due to persistent SARS-CoV-2 positivity. Among them, anal viral detection was positive in 15/21 (71.4%) patients and there was replication in the GI tract in 3/16 (18.7%) patients, with no respiratory tract replication. They hypothesize there is viral rebound due to decreased levels of IgA and IgG antibodies to the viral receptor-binding domain (RBD) and thus, a lack of protective humoral immune response suggesting this leads to persistence of SARS-CoV-2 in the GI tract along with active viral shedding.

Transmission & Prevention

· Climatic influence on the magnitude of COVID-19 outbreak was explored via a stochastic model-based global analysis. Researchers evaluated the effect of climates on COVID-19 transmission in 228 cities across 3 climatic zones. They found that the temperature and humidity may be major contributors to COVID-19 transmission. Average temperatures and relative humidity were the primary contributors in Europe, diurnal temperatures were most important for India, and temperature seasonality was most important for Brazil. These findings highlight the relationship between climates and COVID-19 spread and provide more insight into COVID-19 transmission.

R&D: Diagnosis & Treatments

· Two sample pooling strategies for SARS-CoV-2 RNA detection for efficient screening of COVID-19 were compared. Using 23 pools each containing 1 positive sample and either 5 or 9 negatives, authors demonstrated a similar diagnostic sensitivity to individual tests (p<0.005) but pooling viral transport medium resulted in a false negative while pooling swabs resulted in diagnosis without loss of sensitivity. Authors suggests pooling swabs may facilitate testing in higher quantities at lower costs, which could be used where resources are limited, however this strategy would require collecting double swab samples for individual re-testing should a pool test positive.

· Accuracy of serological testing for SARS-CoV-2 antibodies were presented based on first results from a large mixed-method evaluation study. The study looked at 3 ELISAs for accuracy: nucleoprotein (N), S1 domain of spike protein (S1), and Lateral Flow Immunoassay (LFI) for the full-length spike protein. From 1477 patient samples, 112 of which were COVID-19 positive by RT-PCR, authors found specificities exceeded 94% for all 3 assays, with varying sensitivities (88.4% for RBD, 89.3% for S1, and 72.9% for N protein). Within one month follow-up, 52/54 COVID-19 positive samples of tested sera at serum dilutions ≥1:16 were indicative of protective immunity. The authors argue that ELISAs that target the RBD and S1 protein are good candidates for detecting protective immunity from the COVID-19 virus, and thus require further investigation.

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