Bayesian sequential approach to monitor COVID-19 variants through positivity rate from wastewate (preprint)

Trends in COVID-19 infection have changed throughout the pandemic due to myriad factors, including changes in transmission driven by social behavior, vaccine development and uptake, mutations in the virus genome, and public health policies. Mass testing was an essential control measure for curtailing the burden of COVID-19 and monitoring the magnitude of the pandemic during its multiple phases. However, as the pandemic progressed, new preventive and surveillance mechanisms emerged. Implementing vaccine programs, wastewater (WW) surveillance, and at-home COVID-19 tests reduced the demand for mass severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. This paper proposes a sequential Bayesian approach to estimate the COVID-19 positivity rate (PR) using SARS-CoV-2 RNA concentrations measured in WW through an adaptive scheme incorporating changes in virus dynamics. PR estimates are used to compute thresholds for WW data using the CDC thresholds for low, substantial, and high transmission. The effective reproductive number estimates are calculated using PR estimates from the WW data. This approach provides insights into the dynamics of the virus evolution and an analytical framework that combines different data sources to continue monitoring the COVID-19 trends. These results can provide public health guidance to reduce the burden of future outbreaks as new variants continue to emerge. The proposed modeling framework was applied to the City of Davis and the campus of the University of California Davis.

Cardiopulmonary imaging utilization and findings among hospitalized COVID-19 patients in Latin America (From RIMAC: Registry IMAging Cardiopulmonary among hospitalized COVID-19 patients in LATAM) (preprint)

ObjectivesTo describe the use and findings of cardiopulmonary imaging - chest X-ray (cX-ray), echocardiography (cEcho), chest CT (cCT), lung ultrasound (LUS)) and/or cardiac magnetic resonance imaging (cMRI) - in COVID-19-associated hospitalizations in Latin America (LATAM) BackgroundThe SARS-Cov-2 is one of the largest and most active threats to healthcare in living memory. There is an information gap on imaging services resources (ISR) used and their findings during the pandemic in LATAM. MethodsThis was a multicenter, prospective, observational study of COVID-19 inpatients conducted from March to December 2020 from 12 high-complexity centers in nine LATAM countries. Adults (> 18 yrs) with at least one imaging modality performed, followed from admission until discharge and/or in-hospital death, were included. ResultsWe studied 1435 hospitalized patients (64% males) with a median age of 58 years classified into three regions: 262 from Mexico (Mx), 428 from Central America and Caribbean (CAC), and 745 from South America (SAm). More frequent comorbidities were overweight/obesity (61%), hypertension (45%), and diabetes (27%). During hospitalization, 58% were admitted to ICU. The in-hospital mortality was 28% (95%CI 25-30) highest in Mx (37%). The most frequent cardiopulmonary imaging performed were cCT (61%)-more frequent in Mx and SAm-, and cX-ray (46%) -significantly used in CAC-. The cEcho was carried out in 18%, similarly among regions, and LUS in 7%, more frequently in Mx. The cMRI was performed in only one patient in the cohort. Abnormal findings on the cX-ray were related to peripheral (63%) or basal infiltrates (52%), and in cCT with ground glass infiltrates (89%). Both were more commonly in Mx. In LUS, interstitial syndrome (56%) was the most related abnormal finding, predominantly in Mx and CAC. ConclusionsThe use and findings of cardiopulmonary imaging in LATAM varied between regions and may have been influenced by clinical needs, the personnel protection measures and/or hospitalization location. Condensed AbstractThe SARS-Cov-2 is one of the largest and most active threats to healthcare in living memory. There is limited information on imaging services resources (ISR) used and their findings during the pandemic in LATAM. To our knowledge, RIMAC aimed the first international, multicenter study at registering the use and findings of cardiopulmonary imaging modalities performed for the diagnosis, prognosis, and treatment of patients hospitalized for infection with SARS-CoV-2 in Latin America. We studied their demographic parameters, comorbidities, in-hospital events, laboratory results, and treatments focusing on their impact in clinical complications.