Identifying early adopters of COVID-19 vaccines in Latin America.

COVID-19 vaccine hesitancy is currently-one of the main obstacles to worldwide herd immunity and socioeconomic recovery. Because vaccine coverage can vary between and within countries, it is important to identify sources of variation so that policies can be tailored to different population groups. In this paper, we analyze the results from a survey designed and implemented in order to identify early adopters and laggers in six big cities located in Argentina, Colombia, Chile, Ecuador, Peru, and Dominican Republic. We find that trust in government and science, accurate knowledge about the value of vaccination and vaccine effects, and perceived risk of getting sick is associated with a higher probability to get vaccinated. We also identify potential laggers such as women and populations with high education but low knowledge about vaccines. We discuss specific strategies to promote vaccination among these populations groups as well as more general strategies designed to gain trust. These findings are specific to the context of Latin America insofar as the underlying factors associated with the choice to be vaccinated vary significantly by location and in relation to individual-level factors.

Glycemic control is associated with lower odds of mortality and successful extubation in severe COVID-19.

CONTEXT: Corticosteroids, specifically dexamethasone, have become the mainstay of treatment for moderate to severe COVID-19. Although the RECOVERY trial did not report adverse effects of corticosteroids, the METCOVID (Methylprednisolone as Adjunctive Therapy for Patients Hospitalized with COVID-19) study reported a higher blood glucose level in patients receiving methylprednisolone. OBJECTIVES: This study aims to analyze the association between corticosteroids and COVID-19-related outcomes in patients admitted to the medical ICU (MICU) for COVID-19 pneumonia. METHODS: This is an observational study of 141 patients admitted to the MICU between March 18 and June 7, 2020. Data on demographics, laboratory and imaging studies, and clinical course were obtained, including data on corticosteroid use. Bivariate analyses and logistic regression were performed between patient characteristics and mortality and successful extubation. RESULTS: Of the 141 patients, 86 required mechanical ventilation, 50 received steroids, and 71 died. Regarding demographics, patients had a median age of 58 (interquartile range [IQR] 48, 65), Hispanic (57.4%, n=81), and non-Hispanic Black (37.5%, n=53). The most prevalent comorbidities were hypertension (49.6%, n=70) and diabetes (48.2%, n=68). Lower blood glucose levels on admission (125.5 vs. 148 mg/dL, p=0.025) and lower peak blood glucose levels on corticosteroids (215.5 vs. 361 mg/dL, p=0.0021) were associated with lower prevalence of mortality. Patients who were successfully extubated had a lower admission blood glucose (126.5 vs. 149 mg/dL, p=0.0074) and lower peak blood glucose on corticosteroids (217 vs. 361 mg/dL, p=0.0023). CONCLUSIONS: Lower blood glucose on admission and lower maximum blood glucose on corticosteroids were associated with lower odds of mortality and successful extubation, regardless of preexisting diabetes. Hyperglycemia may be negating any potential benefit of corticosteroid therapy. These findings suggest that glucose control could be a parameter that impacts the outcome of patients receiving corticosteroids for COVID-19 pneumonia.

Infection Transmission and Prevention in Metropolises with Heterogeneous and Dynamic Populations

Due to dense social contacts, metropolises are considered as epicenters of contagious infectious diseases. Developing models for infection transmission and mitigation in metropolises is a challenging problem because of spatiotemporal variations in their population structures. Employing the fact that intra-urban mobility is mainly shaped by the transportation infrastructure and reflected in the traffic flux information, a novel multi-scale reaction-diffusion process is developed to model infection transmission in a metropolis. To mitigate the infection, the impact of three non-pharmaceutical preventive interventions (movement restrictions, social distancing, and proactive testing/screening) is analytically investigated on the reaction-diffusion process. We show that imposing movement restrictions between sub-urban areas is only beneficial when they have different reproduction numbers. The social distancing reduces the infection peak in sub-urban areas, but its impact on the entire metropolis is various: The social distancing reduces a metropolis's infection peak if its implementation disperses the reproduction number of sub-urban areas. We show that allocation schemes of proactive testing/screening teams to sub-urban areas have intractable impacts on the infection peak. This demonstrates the necessity of employing optimization techniques to design the best allocation scheme. Finally, three mathematical models and their solution approaches are developed to optimize the implementation of the interventions with the least economic burden. The performance of the optimization models is compared with two simpler implementation schemes (uniform and pro rata implementations of interventions) using the information of Sioux Falls metropolitan area in the U.S.