Targeted vaccination and the speed of SARS-CoV-2 adaptation

The limited supply of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) raises the question of targeted vaccination. Many countries have opted to vaccinate older and more sensitive hosts first to minimize the disease burden. However, what are the evolutionary consequences of targeted vaccination? We clarify the consequences of different vaccination strategies through the analysis of the speed of viral adaptation measured as the rate of change of the frequency of a vaccine-adapted variant. We show that such a variant is expected to spread faster if vaccination targets individuals who are likely to be involved in a higher number of contacts. We also discuss the pros and cons of dose-sparing strategies. Because delaying the second dose increases the proportion of the population vaccinated with a single dose, this strategy can both speed up the spread of the vaccine-adapted variant and reduce the cumulative number of deaths. Hence, strategies that are most effective at slowing viral adaptation may not always be epidemiologically optimal. A careful assessment of both the epidemiological and evolutionary consequences of alternative vaccination strategies is required to determine which individuals should be vaccinated first.

Aktinische Keratose: Tageslicht PDT zeigt umfassendes Wirkspektrum

Actinic keratoses are a chronic condition in ultraviolet-damaged skin, with a risk of progressing to invasive skin cancer. The aim of this study was to investigate the preventive potential of field-directed repetitive daylight photodynamic therapy for actinic keratoses. A randomized trial was performed, including 58 patients with ≥5 actinic keratoses on photodamaged facial skin, who received either 5 full-face sessions of daylight photodynamic therapy within a period of 2 years or lesion-directed cryosurgery. Primary outcome was the mean cumulative number of new actinic keratoses developed between visits 2 and 6 (visit 6 being a follow-up). This outcome was lower after daylight photo-dynamic therapy (7.7) compared with cryosurgery (10.2), but the difference did not reach significance (–2.5, 95% confidence interval –6.2 to 1.2; p = 0.18). Several signs of photoageing (fine lines, pigmentation, roughness, erythema, sebaceous gland hyperplasia) were significantly reduced after daylight photodynamic therapy, but not after cryosurgery. Significantly less pain and fewer side-effects were reported during daylight photodynamic therapy than during cryosurgery. This study found that repetitive daylight photodynamic therapy had photo-rejuvenating effects. However, the prevention of actinic keratoses by this therapy could not be proven in a statistically reliable manner.

The Rise in Norovirus-Related Acute Gastroenteritis During the Fight Against the COVID-19 Pandemic in Southern China

Background: There has been a significant decline in the morbidity of almost all infectious diseases during the COVID-19 pandemic. However, while the incidence of norovirus-related acute gastroenteritis declined in Guangzhou, China during the initial period of the pandemic, incidence increased significantly once the new school year began in September 2020.Methods: Norovirus-related acute gastroenteritis clusters and outbreaks were assessed in Guangzhou from 2015 to 2020. Medians and interquartile ranges were compared between groups using the Mann–Whitney U-test, and attack rates were calculated.Results: While 78,579 cases of infectious diarrhea were reported from 2015 to 2019, with an average of 15,716 cases per year, only 12,065 cases of infectious diarrhea were reported in 2020. The numbers of sporadic cases and outbreaks reported from January to August 2020 were lower than the average numbers reported during the same time period each year from 2015 to 2019 but began to increase in September 2020. The number of cases in each reported cluster ranged from 10 to 70 in 2020, with a total of 1,280 cases and an average attack rate of 5.85%. The median number of reported cases, the cumulative number of cases, and the attack rate were higher than the average number reported each year from 2015 to 2019. The intervention time in 2020 was also higher than the average intervention time reported during 2015–2019. The main norovirus genotypes circulating in Guangzhou during 2015–2020 included genogroup 2 type 2 (GII.2) (n = 79, 26.69%), GII.17 (n = 36, 12.16%), GII.3 (n = 27, 9.12%), GII.6 (n = 8, 2.7%), GII.4 Sydney_2012 (n = 7, 2.36%), and GII.4 (n = 6, 2.03%).Conclusions: Our findings illustrate the importance of maintaining epidemiological surveillance for viral gastroenteritis during the COVID-19 pandemic. Local disease prevention and control institutions need to devote sufficient human resources to control norovirus clusters.

SARS-CoV-2 antibody seroprevalence in Lebanon: findings from the first nationwide serosurvey

Background Lebanon, a small country in the Middle East, remains severely affected by the COVID-19 pandemic. Seroprevalence surveys of anti-SARS-CoV-2 antibodies provide accurate estimates of SARS-CoV-2 infection and hence evaluate the extent of the pandemic. The present study aimed to evaluate the prevalence of SARS-CoV-2 antibodies in Lebanon and to compare the estimated cumulative number of COVID-19 cases with the officially registered number of laboratory-confirmed cases up to January 15, 2021. Methods A nationwide population-based serosurvey study was conducted in Lebanon between December 7, 2020, and January 15, 2021, before the initiation of the national vaccination program. The nCOVID-19 IgG & IgM point-of-care (POCT) rapid test was used to detect the presence of anti-SARS-COV-2 immunoglobulin G (IgG) in the blood. Seroprevalence was estimated after weighting for sex, age, and area of residence and adjusting for the test performance. Results Of the 2058 participants, 329 were positive for IgG SARS-COV-2, resulting in a crude seroprevalence of 16.0% (95% CI 14.4–17.6). The weighed seroprevalence was 15.9% (95% CI of 14.4 and 17.4). After adjusting for test performance, the population weight-adjusted seroprevalence was 18.5% (95% CI 16.8–20.2). This estimate implies that 895,770 individuals of the general population were previously infected by COVID-19 up to January 15, 2021 in Lebanon. The overall estimated number of subjects with previous SARS-CoV-2 infection was three times higher than the officially reported cumulative number of confirmed cases. Seroprevalence was similar across age groups and sexes (p-value > 0.05). However, significant differences were revealed across governorates. Conclusions Our results suggest that the Lebanese population is still susceptible to SARS-CoV-2 infection and far from achieving herd immunity. These findings represent an important contribution to the surveillance of the COVID-19 pandemic in Lebanon and to the understanding of how this virus spreads. Continued surveillance for COVID-19 cases and maintaining effective preventive measures are recommended to control the epidemic spread in conjunction with a national vaccination campaign to achieve the desired level of herd immunity against COVID-19.

Modeling the COVID-19 Epidemic With Multi-Population and Control Strategies in the United States

As of January 19, 2021, the cumulative number of people infected with coronavirus disease-2019 (COVID-19) in the United States has reached 24,433,486, and the number is still rising. The outbreak of the COVID-19 epidemic has not only affected the development of the global economy but also seriously threatened the lives and health of human beings around the world. According to the transmission characteristics of COVID-19 in the population, this study established a theoretical differential equation mathematical model, estimated model parameters through epidemiological data, obtained accurate mathematical models, and adopted global sensitivity analysis methods to screen sensitive parameters that significantly affect the development of the epidemic. Based on the established precise mathematical model, we calculate the basic reproductive number of the epidemic, evaluate the transmission capacity of the COVID-19 epidemic, and predict the development trend of the epidemic. By analyzing the sensitivity of parameters and finding sensitive parameters, we can provide effective control strategies for epidemic prevention and control. After appropriate modifications, the model can also be used for mathematical modeling of epidemics in other countries or other infectious diseases.

Evaluation on public and private health care delivery in COVID19

Background: In Korea, there are two healthcare delivery sectors: public and private. The purpose of this study is to compare public and private healthcare delivery in the context of COVID-19 and evaluate healthcare delivery to patients with medical benefits.Methods: Data from the Korea Centersfor Disease Control and Prevention (KCDC), the Health Insurance Reviewand Assessment Service claimdata, and the Ministry ofHealth andWelfarewere analyzed fromJanuary 2020 to February 2021.Results: During the observation period, the cumulative number of patients with the most severe cases was 1,566, and the proportion of inpatients with the most severe cases by healthcare facilities types were: 44.2% (692 patients) in regional public hospitals, 8.9% (140 patients) in national university hospitals, and 22.9% (358 patients) in other types of public hospitals, and 24.0% (376 patients) of private hospitals. The proportion of patients receiving medical benefits by health care institutions was 13.9% in regional public hospitals, 6.7% in national university hospitals, and 7.1% in other public hospitals.Conclusions: The debate about the roles and functions of public and private hospitalsis ongoing. Ratherthan classifying according to the establishment entity, it is necessary to seek ways to achieve the ultimate goal of the medical system, which isto protect people’slives and promote health.

Medical Students’ Mental Health Status and Coping Strategies in Their Quarantine Period During COVID-19 Pandemic in Universiti Putra Malaysia

Movement control order (MCO) was enforced by the Malaysian government on 18th March 2020 due to sudden increase in the cumulative number of COVID-19 cases. University students, including medical students, were among the group of the population which were significantly affected. This study was conducted among medical students in Universiti Putra Malaysia (UPM) to compare the mental health status and coping strategies, between gender and phase of the clinical study related to their quarantine status between 18th March 2020 to 9th June 2020. This was a cross-sectional study involving the undergraduate medical students in UPM in the academic year of 2019/2020 during the MCO. A stratified random sampling method was used; a total of 173 respondents which includes students of Year 1 to Year 5 participated. The study was conducted after five months since the first day of MCO, for one week period of data collection. The mental health status was assessed using Depression, Anxiety and Stress Scale 21-item (DASS-21) questionnaire. Four-point Likert scale was scored to determine the degree of severity. The coping strategies was assessed using Brief-COPE (Coping Orientation to Problems Experienced) in which four-point Likert scale was used as well, and the total marks were grouped into four coping strategies. This study found higher scores of DASS-21 in the non-quarantined group and approach method was considered as a favourable coping strategy in both groups. In the quarantined group, female and clinical students showed higher scores of DASS-21. In the non-quarantined group, clinical students showed a significantly higher score of stress while male students significantly used their humour as coping strategies.

DriverRWH: Discovering Cancer Driver Genes By Random Walk On a Gene Mutation Hypergraph

Background: Recent advances in next-generation sequencing technologies have helped investigators generate massive amounts of cancer genomic data. A critical challenge in cancer genomics is identification of a few driver mutation genes from a much larger number of passenger mutation genes. However, majority of existing computational approaches underuse the co-occurrence information of the individuals, which deems to be important in tumorigenesis and tumor progression. Driver gene list predicted from these tools are prone to be false positive, recent research is far from achieving the ultimate goal of discovering a complete catalog of driver genes. Results: To make full use of co-mutation information, we present a random walk algorithm referred to as DriverRWH on a weighted gene mutation hypergraph model, using somatic mutation data and molecular interaction network data to prioritize candidate driver genes. Applied to tumor samples of different cancer types from The Cancer Genome Atlas (TCGA), DriverRWH shows significantly better performance than state-of-art prioritization methods in terms of the area under the curve (AUC) scores and the cumulative number of known driver genes recovered in top-ranked candidate genes. DriverRWH recovers approximately 50% known driver genes in the top 30 ranked candidate genes for more than half of the cancer types. In addition, DriverRWH is also highly robust to perturbations in the mutation data and gene functional network data. Conclusion: DriverRWH is effective among various cancer types in prioritizes cancer driver genes and provides considerable improvement over other tools with a better balance of precision and sensitivity. It can be a useful tool for detecting potential driver genes and facilitate targeted cancer therapies.

Comparison of selected mathematical functions for the analysis of growth behavior of items and physical interpretation of AvramiWeibull function

Empirical data of sigmoidal-shaped y(t) growth behavior of different types of items, such as papers and citations earned by individual and all successively published papers of selected top-cited authors, germination of tomato seeds and three different bacteria, are analyzed and compared by Avrami-Weibull, Verhulst (logistic) and Gompertz functions. It was found that: (1) Avrami-Weibull function describes different types of the data better than Gompertz and Verhulst funtions, and (2), in comparison with Verhulst and Gompertz functions, Avrami-Weibull function, expressed in the form: y(t)/ymax = 1-exp[(t/Q)q] (where ymax is the maximum value of y(t) when t ® ¥, and Q and q are constants), is equally very versatile in explaining the generation rate dy(t)/dt of items in terms of its parameters Q and q. Using the basic concepts involved in the derivation of Avrami-Weibull function for overall crystallization from melt and supersaturated solution, the growth behavior of cumulative number y(t) of items produced at time t by individual (simple) sources and collectives or groups of simple sources (i.e. complex or composite sources) is presented. Comparison of the process of receiving of citations by papers with the processes of occurrence of chemical reactions and crystallization of solid phases from melts and supersaturated solutions shows that this process is similar to that of overall crystallization of solid phases from melts and solutions. Analysis of growth of citations using Avrami-Weibull function to individual papers published by different authors shows that 1 < q < 4 for most cases. This suggests that the process of citations to individual articles is mainly determined by progressive nucleation mode involving both diffusion and integration of published knowledge.

Modeling The Impact of Vaccination On COVID-19 And Its Delta Variant

Vaccination is an important means to fight against the spread of the SARS-CoV-2 virus and its variants. In this work, we propose a general susceptible-vaccinated-exposed-infected-hospitalized-removed (SVEIHR) model and derive its basic and effective reproduction numbers. We set Hong Kong as an example to prove the validity of our model. The model shows how the number of confirmed COVID-19 cases in Hong Kong during the second and third waves of the COVID-19 pandemic would have been reduced had vaccination been available then. We then investigate the relationships between various model parameters and the cumulative number of hospitalized COVID-19 cases in Hong Kong for the ancestral and Delta strains of the virus. Next, we compare the evolution of the SVEIHR model to the traditional “herd immunity” threshold where the proportion of vaccinated individuals is static and no further vaccination takes place after model initialization. Numerical results for Hong Kong demonstrate that the static herd immunity threshold corresponds to a cumulative hospitalization ratio of about one percent (assuming the current hospitalization rate of infected individuals is maintained). We also demonstrate that when the vaccination rate is high, the initial proportion of vaccinated individuals can be lowered for while still maintaining the same proportion of cumulative hospitalized individuals.