Vaccination Schedule under Conditions of Limited Vaccine Production Rate

The paper is devoted to optimal vaccination scheduling during a pandemic to minimize the probability of infection. The recent COVID-19 pandemic showed that the international community is not properly prepared to manage a crisis of this scale. Just after the vaccines had been approved by medical agencies, the policymakers needed to decide on the distribution strategy. To successfully fight the pandemic, the key is to find the equilibrium between the vaccine distribution schedule and the available supplies caused by limited production capacity. This is why society needs to be divided into stratified groups whose access to vaccines is prioritized. Herein, we present the problem of distributing protective actions (i.e., vaccines) and formulate two mixed-integer programs to solve it. The problem of distributing protective actions (PDPA) aims at finding an optimal schedule for a given set of social groups with a constant probability of infection. The problem of distributing protective actions with a herd immunity threshold (PDPAHIT) also includes a variable probability of infection, i.e., the situation when herd immunity is obtained. The results of computational experiments are reported and the potential of the models is illustrated with examples.

Optimizing pre-clerkship medical education at the University of Ottawa

COVID-19 has brought forth unprecedented changes in the delivery of medical education. With concerns rising over a new variant and an upheaval in vaccine distribution, institutions have had to re-strategize and, in many cases, implement provisional shutdowns to contain the spread of SARS-CoV-2. For medical schools, providing an optimal balance between in-person training and virtual learning has been challenging. At the University of Ottawa Faculty of Medicine, key components of the undergraduate medical education, including in-class lectures, interactive practical sessions, and clinical placements, have been affected by the pandemic. In this paper, we highlight barriers to an optimal learning experience among pre-clerkship students at the University of Ottawa and propose ways in which this can be overcome.

Modelling COVID-19 Vaccine Breakthrough Infections in Highly Vaccinated Israel - the effects of waning immunity and third vaccination dose

In August 2021, a major wave of the SARS-CoV-2 Delta variant erupted in the highly vaccinated population of Israel. The Delta variant has a transmission advantage over the Alpha variant, and thus replaced it in approximately two months. The outbreak led to an unexpectedly large proportion of breakthrough infections (BTI)-- a phenomenon that received worldwide attention. The BTI proportion amongst cases in the age group of 60+ years reached levels as high as ~85% in August 2021. Most of the Israeli population, especially those 60+ age, received their second dose of the vaccination, four months before the invasion of the Delta variant. Hence, either the vaccine induced immunity dropped significantly or the Delta variant possesses immunity escaping abilities. In this work, we analyzed and model age-structured cases, vaccination coverage, and vaccine BTI data obtained from the Israeli Ministry of Health, to help understand the epidemiological factors involved in the outbreak. We propose a mathematical model which captures a multitude of factors, including age structure, the time varying vaccine efficacy, time varying transmission rate, BTIs, reduced susceptibility and infectivity of vaccinated individuals, protection duration of the vaccine induced immunity, and the vaccine distribution. We fitted our model to the cases among vaccinated and unvaccinated, for <60 and 60+ age groups, to address the aforementioned factors. We found that the transmission rate was driven by multiple factors including the invasion of Delta variant and the mitigation measures. Through a model reconstruction of the reproductive number R0(t), it was found that the peak transmission rate of the Delta variant was 1.96 times larger than the previous Alpha variant. The model estimated that the vaccine efficacy dropped significantly from >90% to ~40% over 6 months, and that the immunity protection duration has a peaked Gamma distribution (rather than exponential). We further performed model simulations quantifying the important role of the third vaccination booster dose in reducing the levels of breakthrough infections. This allowed us to explore "what if" scenarios should the booster not have been rolled out. Application of this framework upon invasion of new pathogens, or variants of concern, can help elucidate important factors in the outbreak dynamics and highlight potential routes of action to mitigate their spread.

Has the COVID-19 Pandemic Impacted Interest in Cosmetic Facial Plastic Surgery?: A Google Trends Analysis

Facial cosmetic surgery trends are evolving in the current climate of the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to evaluate public interest in elective facial plastic surgery during the COVID-19 pandemic including the period of the COVID-19 vaccine distribution using Google Trends. A Google Trends analysis was completed using popular terms related to facial cosmetic surgery and procedures from March 2017 to August 2021. Three stages were identified (baseline, pre-COVID-19 vaccine distribution, and post-COVID-19 vaccine distribution). Descriptive statistics were calculated and two-tailed t-tests were performed between the pre-vaccine and the post-vaccine phases. Linear regression analysis was also performed to determine percent deflection of search terms. There was significantly greater interest in facial aesthetic procedure search terms, except for tear trough filler, during the post-COVID-19 vaccine phase compared with the pre-COVID-19 vaccine phase. There was greater interest in lower facial procedure interest during this phase compared with upper facial procedures (p-value = 0.0011). The search terms with the greatest deflection percentage during the post-vaccine phase were lip filler, brow lift, and lip flip. There continues to be high demands of facial plastic surgery and procedures despite COVID-19 pandemic.

EU ANTI-COVID POLICY IN THE WESTERN BALKANS

The pandemic generated by COVID-19 has brought new challenges for global politics. For this reason, the EU has been changing its policy towards the Western Balkans. The entire region is known to be engaged in the European integration process, which has received new issues associated with the COVID-19 pandemic. Therefore, the «Team Europe» package was launched on April 2020 to support EU partner countries in response to coronavirus and its consequences. This programme includes the most vulnerable countries of the European Neighborhood Policy, Africa and the Western Balkans. The core task was to back the health system and the socio-economic recovery of the partner states. In addition, the distribution of vaccines against COVID-19, called as «vaccine diplomacy», has become a peculiar policy area. The EU is vigorously involved in this process, especially allocating funds to the COVAX program and its internal distribution mechanisms. Consequently, the purpose of this study is to analyze the effectiveness of the EU anti-crisis policy in the Western Balkans. The article deals with the initial measures implemented by the EU to aid the countries of the region. Moreover, the author touches upon the issue of the launching of the EU’s vaccine distribution process.

Adapting serosurveys for the SARS-CoV-2 vaccine era

Population-level immune surveillance, which includes monitoring exposure and assessing vaccine-induced immunity, is a crucial component of public health decision-making during a pandemic. Serosurveys estimating the prevalence of SARS-CoV-2 antibodies in the population played a key role in characterizing SARS-CoV-2 epidemiology during the early phases of the pandemic. Existing serosurveys provide infrastructure to continue immune surveillance, but must be adapted to remain relevant in the SARS-CoV-2 vaccine era. Here, we delineate how SARS-CoV-2 serosurveys should be designed to distinguish infection- and vaccine-induced humoral immune responses to efficiently monitor the evolution of the pandemic. We discuss how serosurvey results can inform vaccine distribution to improve allocation efficiency in countries with scarce vaccine supplies and help assess the need for booster doses in countries with substantial vaccine coverage.

Vaccine breakthrough and the invasion dynamics of SARS-CoV-2 variants

Vaccination provides a powerful tool for mitigating and controlling the COVID-19 pandemic. However, a number of factors reduce these potential benefits. The first problem arises from heterogeneities in vaccine supply and uptake: from global inequities in vaccine distribution, to local variations in uptake derived from vaccine hesitancy. The second complexity is biological: though several COVID-19 vaccines offer substantial protection against infection and disease, 'breakthrough' reinfection of vaccinees (and subsequent retransmission from these individuals) can occur, driven especially by new viral variants. Here, using a simple epidemiological model, we show that the combination of infection of remaining susceptible individuals and breakthrough infections of vaccinees can have significant effects in promoting infection of invading variants, even when vaccination rates are high and onward transmission from vaccinees relatively weak. Elaborations of the model show how heterogeneities in immunity and mixing between vaccinated and unvaccinated sub-populations modulate these effects, underlining the importance of quantifying these variables. Overall, our results indicate that high vaccination coverage still leaves no room for complacency if variants are circulating that can elude immunity, even if this happens at very low rates.

SARS-CoV-2 attack rate and population immunity in southern New England, March 2020 - May 2021

Estimating an infectious disease attack rate requires inference on the number of reported symptomatic cases of a disease, the number of unreported symptomatic cases, and the number of asymptomatic infections. Population-level immunity can then be estimated as the attack rate plus the number of vaccine recipients who had not been previously infected; this requires an estimate of the fraction of vaccines that were distributed to seropositive individuals. To estimate attack rates and population immunity in southern New England, we fit a validated dynamic epidemiological model to case, clinical, and death data streams reported by Rhode Island, Massachusetts, and Connecticut for the first 15 months of the COVID-19 pandemic, from March 1 2020 to May 31 2021. This period includes the initial spring 2020 wave, the major winter wave of 2020-2021, and the lagging wave of lineage B.1.1.7(Alpha) infections during March-April 2021. In autumn 2020, SARS-CoV-2 population immunity (equal to the attack rate at that point) in southern New England was still below 15%, setting the stage for a large winter wave. After the roll-out of vaccines in early 2021, population immunity in many states was expected to approach 70% by spring 2021, with more than half of this immune population coming from vaccinations. Our population immunity estimates for May 31 2021 are 73.4% (95% CrI: 72.9% - 74.1%) for Rhode Island, 64.1% (95% CrI: 64.0% - 64.4%) for Connecticut, and 66.3% (95% CrI: 65.9% - 66.9%) for Massachusetts, indicating that >33% of southern Englanders were still susceptible to infection when the Delta variant began spreading in July 2021. Despite high vaccine coverage in these states, population immunity in summer 2021 was lower than planned due to 34% (Rhode Island), 25% (Connecticut), and 28% (Massachusetts) of vaccine distribution going to seropositive individuals. Future emergency-setting vaccination planning will likely have to consider over-vaccination as a strategy to ensure that high levels of population immunity are reached during the course of an ongoing epidemic.