Sebastian A. Rodriguez-Cartes

Background Coronavirus Disease 2019 (COVID-19) continues to cause significant hospitalizations and deaths in the United States. Its continued burden and the impact of annually reformulated vaccines remain unclear. Here, we present projections of COVID-19 hospitalizations and deaths in the United States for the next 2 years under 2 plausible assumptions about immune escape (20% per year and 50% per year) and 3 possible CDC recommendations for the use of annually reformulated vaccines (no recommendation, vaccination for those aged 65 years and over, vaccination for all eligible age groups based on FDA approval). Methods and findings The COVID-19 Scenario Modeling Hub solicited projections of COVID-19 hospitalization and deaths between April 15, 2023 and April 15, 2025 under 6 scenarios representing the intersection of considered levels of immune escape and vaccination. Annually reformulated vaccines are assumed to be 65% effective against symptomatic infection with strains circulating on June 15 of each year and to become available on September 1. Age- and state-specific coverage in recommended groups was assumed to match that seen for the first (fall 2021) COVID-19 booster. State and national projections from 8 modeling teams were ensembled to produce projections for each scenario and expected reductions in disease outcomes due to vaccination over the projection period. From April 15, 2023 to April 15, 2025, COVID-19 is projected to cause annual epidemics peaking November to January. In the most pessimistic scenario (high immune escape, no vaccination recommendation), we project 2.1 million …

We assessed the potential impact of introducing rubella-containing vaccine (RCV) on congenital rubella syndrome (CRS) incidence in Afghanistan (AFG), Democratic Republic of Congo (COD), Ethiopia (ETH), Nigeria (NGA), and Pakistan (PAK). We simulated several RCV introduction scenarios over 30 years using a validated mathematical model. Our findings indicate that RCV introduction could avert between 86,000 and 535,000 CRS births, preventing 2.5 to 15.8 million disability-adjusted life years. AFG and PAK could reduce about 90% of CRS births by introducing RCV with current measles routine coverage and executing supplemental immunization activities (SIAs). However, COD, NGA, and ETH must increase their current routine vaccination coverage to reduce CRS incidence significantly. This study showcases the potential benefits of RCV introduction and reinforces the need for global action to strengthen immunization programs.

The involvement of spontaneous volunteers (SVs) in disaster response represents a significant resource. However, existing emergency management plans often fail to take spontaneous volunteers into account due to negative perceptions and uncertainty about SV convergence. We developed an agent-based simulation model of spontaneous volunteer convergence to aid the disaster response planning process. The model considers a heterogeneous population of agents, each with unique attributes such as motivation, opinion, and site choice behavior. Model development was informed by the literature as well as interviews with volunteers and volunteer managers, participant observations, and discussions with practitioners. To illustrate the practical value of the model, we present a case study that addressed research questions related to volunteer reception centers and volunteer assignment policies. This …

This work proposes a framework to aid the strategic decision making regarding the proper location of fire stations as well as their assignment of vehicles to improve emergency response. We present an iterative simulation–optimization approach that based on some precomputed utilization parameters updates the optimal location of vehicles and fire stations. First, we find an optimal solution by using a robust formulation of the Facility Location and Equipment Emplacement Technique with Expected Coverage (Robust FLEET-EXC) model, which maximizes demand considering vehicles’ utilization. Second, we use this solution as an input to a discrete event simulation model to compute utilization parameters. Then, if the obtained parameters deviate less than a desired error, the solution is maintained; otherwise, a new solution is computed with these new parameters. Additionally, the emergencies arrival process is …

In this paper, the Facility Location and Equipment Emplacement Technique model with Expected Covering (FLEET-EXC) model is introduced, an emergency facility location problem that maximizes the coverage of expected demand. This model also considers multiple regions, demand types, vehicle types, and region-dependent dispatching rules. This work presents a mixed-integer linear programming model that considers vehicles average utilization to compute expected demand coverage. Because the optimal solution depends on these parameters, we propose an iterative procedure as a solving method, where a Hypercube Queueing Model is used to compute the utilization of the vehicles. The goal of this procedure is to update parameters until the resulting vehicle utilizations from the optimal solution are the same as the ones used to compute the expected demand of the MIP mentioned above model. Finally, a …