August 28, 2020

On today's episode we discuss: —Climate: Primary care residents at Brigham and Women's Hospital in Boston discuss the importance of community health centers (CHCs) in serving low socioeconomic status, immigrant, rural, and racial/ethnic minority patients during the COVID-19 pandemic. The authors call for Congressional action to ensure adequate funding to CHCs and universal coverage to individuals without employer-sponsored insurance, suggesting that the pandemic may provide an impetus for improving the United States healthcare system so that CHC's could serve patients more effectively. —Epidemiology: A multicenter cross-sectional study found that among 614 patients with confirmed COVID-19, 278 had elevated troponin levels, which was associated with higher in-hospital mortality. Those with elevated troponin levels were more likely to be older, have atrial fibrillation, heart failure, hypertension, and coronary artery disease. In the hospital, patients with elevated troponins were additionally more likely to have complications including sepsis, pulmonary embolism, delirium, heart failure, acute kidney failure, and major bleeding. This study suggests that running diagnostic tests and identifying patients with elevated troponins may help earlier identify patients requiring more intensive care. —Understanding the Pathology: A retrospective study of 191 severe COVID-19 patients looked specifically at longitudinal IgM and IgG antibody responses to the nucleocapsid, spike protein, and receptor-binding domain of SARS-CoV-2. There was no significant difference in antibody positive rates between survivors vs non-survivors nor 28-day clinically improved vs non-improved patients. Four weeks after infection, patients who ultimately died had lower spike-IgG titers than survivors, and viral clearance was strongly associated with nucleocapsid-IgG and receptor binding domain-IgG titers, suggesting the possible use of spike-IgG as a predictor of adverse outcomes and the role of IgG as an important factor against SARS-CoV-2 infection. —Transmission & Prevention: A medical news reporter discussed the herd immunity threshold for COVID-19, stating that determining this threshold is difficult with this virus due to the many uncertainties about the level at which people can act as vectors of disease spread. This author also suggests that even if herd immunity is be achieved, there is no guarantee that it would last. —R&D: Diagnosis & Treatments: Epidemiologists in Spain examined the avidity of antibodies to SARS-CoV-2 in 76 serum specimens from COVID-19 patients to determine whether antibody avidity corresponded with time since acquisition of the virus. They found that 39 samples tested positive for both IgG and IgM, 37 tested positive for IgG only, and IgG reactivity was lost in 28 samples after urea treatment. Serum that lost reactivity were drawn significantly sooner after onset of symptoms than serum that retained activity suggesting that serum antibody avidity corresponds to the time since onset of symptoms and thus could be useful in predicting the acquisition date of SARS-CoV-2 infection.