The Failures of an Ideal COVID-19 Vaccine: A Simulation Study

This paper simulates an ideal COVID-19 vaccine that confers immediate sterilizing immunity against all SARS-CoV-2 variants. The purpose was to explore how well this ideal vaccine could protect a population against common conditions (such as vaccine hesitancy) that might impair vaccine effectiveness. Simulations were done with an SEIRS spreadsheet model that ran two parallel subpopulations: one that accepted vaccination, and another that refused it. The two subpopulations could transmit infections to one another. Success was judged by the rate of new cases in the period from 1-5 years after the introduction of the vaccine. Under good conditions, including a small subpopulation that refused vaccination, rapid distribution of the vaccine, duration of vaccinal immunity longer than 12 months, good retention of interest in getting vaccinated after the first year, strict maintenance of nonpharmaceutical interventions (NPIs) such as masking, and new variants with R0s less than 4.0, the vaccine was able to end the epidemic. With violation of these conditions, the post-vaccine era futures ranged from endemic COVID at a low or medium level to rates of COVID cases worse than anything seen in the US up to late 2021. The most important conditions for keeping case rates low were a fast speed of vaccine distribution, a low percentage of the population that refuses vaccination, a long duration of vaccinal immunity, and continuing maintenance of NPIs after vaccination began. On the other hand, a short duration of vaccinal immunity, abandonment of NPIs, and new variants with a high R0 were powerful barriers to disease control. New variants with high R0s were particularly damaging, producing high case rates except when vaccination speed was unrealistically rapid. A recurring finding was that most disease afflicting the vaccinated population in these simulations originated in the unvaccinated population, and cutting off interaction with the unvaccinated population caused a sharp drop in the case rate of the vaccinated population. In conclusion, multiple common conditions can compromise the effectiveness of even an ideal vaccine.

DESENVOLVIMENTO DE PLANILHA COMO FERRAMENTA DE APOIO NO PLANEJAMENTO DIETÉTICO

A tecnologia está cada vez mais presente na área da nutrição. Existem diversos softwares presentes no mercado e muitos são voltados para o uso do profissional nutricionista. Porém, dentro das salas de aula, os programas ainda são pouco utilizados. Nessa linha de pensamento, foi desenvolvido um modelo de planilha de nutrição, que auxiliará o aluno e até mesmo o profissional nutricionista na elaboração de planos alimentares e cálculos antropométricos. A planilha proposta está dividida em cinco setores: “Cardápio” – seleção dos alimentos do plano alimentar, com medidas caseiras e quantidades (g/ml); “Adicionar alimento” – adicionar um alimento não presente no banco de dados; “Cálculo de VET” – cálculo das necessidades calóricas de um indivíduo e distribuição das calorias nas refeições; “Antropometria” – avaliação antropométrica do indivíduo e “Medidas caseiras” – lista com alimentos e suas medidas caseiras. A utilização de planilhas para planejamento alimentar auxilia na prescrição de cardápio e avaliação do indivíduo por parte dos alunos de nutrição e profissionais nutricionistas. THE DEVELOPMENT OF A SPREADSHEET AS A SUPPORT TOOL IN DIETARY PLANNING ABSTRACT The use of technology is increasingly present in the nutritional area. There are several software programs on the market, and many of them are designed to be used by professional nutritionists. However, in the classrooms, those programs are still poorly used. In this line of thought, a nutrition spreadsheet model was developed, which will assist the student and even the professional nutritionist in the preparation of food planning and anthropometric calculations. The suggested spreadsheet is divided into five sectors: "Menu" - selection of foods for the food plan, with measurements and quantities (g/ml); "Add food" - to include food not present in the database; "TCV Calculation" - to calculate the caloric needs of an individual and distribute the calories in the meals; "Anthropometry" - anthropometric evaluation of the individual and "Home Measures" - a list with foods and their home measures. The use of food planning worksheets helps in the menu prescription and evaluation of the individual by both nutrition students and nutrition professionals. Descriptors: Nutrition. Food planning. Worksheet. Technology.

Optimizing the Operation Release Policy Using Charged System Search Algorithm: A Case Study of Klang Gates Dam, Malaysia

In planning and managing water resources, the implementation of optimization techniques in the operation of reservoirs has become an important focus. An optimal reservoir operating policy should take into consideration the uncertainty associated with uncontrolled reservoir inflows. The charged system search (CSS) algorithm model is developed in the present study to achieve optimum operating policy for the current reservoir. The aim of the model is to minimize the cost of system performance, which is the sum of square deviations from the distinction between the release of the target and the actual demand. The decision variable is the release of a reservoir with an initial volume of storage, reservoir inflow, and final volume of storage for a given period. Historical rainfall data is used to approximate the inflow volume. The charged system search (CSS) is developed by utilizing a spreadsheet model to simulate and perform optimization. The model gives the steady-state probabilities of reservoir storage as output. The model is applied to the reservoir of Klang Gates for the development of an optimal reservoir operating policy. The steady-state optimal operating system is used in this model.

The COVID-19 Incarceration Model: a tool for corrections staff to analyze outbreaks of COVID-19

Correctional facilities are at high risk of COVID-19 outbreaks due to the inevitable close contacts in the environment. Such facilities are a high priority in the public health response to the epidemic. We developed a user-friendly Excel spreadsheet model (building on the previously developed Recidiviz model) to analyze COVID-19 outbreaks in correctional facilities and the potential impact of prevention strategies -the COVID-19 Incarceration Model. The model requires limited inputs and can be used by non-modelers. The impact of a COVID-19 outbreak and mitigation strategies is illustrated for an example prison setting.

Model Calculations of Aerosol Transmission and Infection Risk of COVID-19 in Indoor Environments

ABSTRACTThe role of aerosolized SARS-CoV-2 viruses in airborne transmission of COVID-19 is debated. The transmitting aerosol particles are generated through the breathing and vocalization by infectious subjects. Some authors state that this represents the dominant route of spreading, while others dismiss the option. Public health organizations generally categorize it as a secondary transmission pathway. Here we present a simple, easy-to-use spreadsheet model to estimate the infection risk for different indoor environments, constrained by published data on human aerosol emissions, SARS-CoV-2 viral loads, infective dose and other parameters. We evaluate typical indoor settings such as an office, a classroom, a choir practice room and reception/party environments. These are examples, and the reader is invited to use the algorithm for alternative situations and assumptions. Our results suggest that aerosols from highly infective subjects can effectively transmit COVID-19 in indoor environments. This “highly infective” category represents approximately twenty percent of the patients tested positive for SARS-CoV-2. We find that “super infective” subjects, representing the top five to ten percent of positive-tested ones, plus an unknown fraction of less, but still highly infective, high aerosol-emitting subjects, may cause COVID-19 clusters (>10 infections), e.g. in classrooms, during choir singing and at receptions. The highly infective ones also risk causing such events at parties, for example. In general, active room ventilation and the ubiquitous wearing of face masks (i.e. by all subjects) may reduce the individual infection risk by a factor of five to ten, similar to high-volume HEPA air filtering. The most effective mitigation measure studied is the use of high-quality masks, which can drastically reduce the indoor infection risk through aerosols.