Epidemiology
· Association Between Upper Respiratory Tract Viral Load, Comorbidities, Disease Severity, and Outcome of Patients With SARS-CoV-2 Infection: Epidemiologists and microbiologists from the National Public Health Organization in Athens evaluated factors associated with high upper respiratory tract (URT) viral load in 1122 cases of SARS-CoV-2 infection diagnosed between February 26 and May 3, 2020 (Table 1). They found higher viral load was most often observed in patients with comorbidities (i.e. hypertension, obesity, immunosuppression) and patients with high viral load stayed longer in the ICU and required longer intubation than patients with low or moderate viral load (Table 3). Authors suggest URT viral load is a useful predictor of morbidity and severe outcomes in COVID-19.
Transmission & Prevention
· Identifying COVID-19 Risk Through Observational Studies to Inform Control Measures: Physicians from the COVID-19 Response Team from the United States Centers for Disease Control review observational studies investigating settings and occasions associated with higher risk of SARS-CoV-2 spread. They found dining at restaurants and going to bars or coffee shops were associated with a higher odds of a positive SARS-CoV-2 PCR (Figure). They argue that, alongside vaccination, preventative strategies should target high risk activities and must be continually adapted to the current situation to optimally control the pandemic.
· SARS-CoV-2 Serologic Assays in Control and Unknown Populations Demonstrate the Necessity of Virus Neutralization Testing: Immunologists, infectious disease pediatricians, and statisticians from the University of Washington compared combinations of 4 viral antigens and 5 human antibody isotype enzyme-linked immunosorbent assay (ELISA) platforms with 15 positive and 30 negative SARS-CoV-2 controls followed by viral neutralization assessment (Figure 1) in a clinically-relevant cohort of 114 patients from Seattle (Figure 6). They found that SARS-CoV-2 receptor binding domain (RBD) IgG, spike IgG3, and nucleocapsid protein (NP) IgG were the best-performing virus-specific antibody detection platforms in controls, with spike IgG3 most accurately predicting serologically positive individuals with virus neutralization activity (Table 1). The authors conclude that coupling virus neutralization analysis to a spike IgG3 antibody test can indicate individuals' immune protection status for SARS-CoV-2.
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