An efficient nonstandard computer method to solve a compartmental epidemiological model for COVID-19 with vaccination and population migration.

BACKGROUND AND OBJECTIVE: In this manuscript, we consider a compartmental model to describe the dynamics of propagation of an infectious disease in a human population. The population considers the presence of susceptible, exposed, asymptomatic and symptomatic infected, quarantined, recovered and vaccinated individuals. In turn, the mathematical model considers various mechanisms of interaction between the sub-populations in addition to population migration. METHODS: The steady-state solutions for the disease-free and endemic scenarios are calculated, and the local stability of the equilibium solutions is determined using linear analysis, Descartes' rule of signs and the Routh-Hurwitz criterion. We demonstrate rigorously the existence and uniqueness of non-negative solutions for the mathematical model, and we prove that the system has no periodic solutions using Dulac's criterion. To solve this system, a nonstandard finite-difference method is proposed. RESULTS: As the main results, we show that the computer method presented in this work is uniquely solvable, and that it preserves the non-negativity of initial approximations. Moreover, the steady-state solutions of the continuous model are also constant solutions of the numerical scheme, and the stability properties of those solutions are likewise preserved in the discrete scenario. Furthermore, we establish the consistency of the scheme and, using a discrete form of Gronwall's inequality, we prove theoretically the stability and the convergence properties of the scheme. For convenience, a Matlab program of our method is provided in the appendix. CONCLUSIONS: The computer method presented in this work is a nonstandard scheme with multiple dynamical and numerical properties. Most of those properties are thoroughly confirmed using computer simulations. Its easy implementation make this numerical approach a useful tool in the investigation on the propagation of infectious diseases. From the theoretical point of view, the present work is one of the few papers in which a nonstandard scheme is fully and rigorously analyzed not only for the dynamical properties, but also for consistently, stability and convergence.

Face masks and respirators. Choices for health workers in COVID-19 pandemics

COVID-19 has had a significant impact on the health care workers derived, among other factors, due to the lack of adequate personal protection equipment, especially face masks and respirators. The forms of transmission are reviewed, taking into consideration that the main route of infections is through aerosols, microparticles smaller than 60-100 microns that are exhaled during aerosol generating procedures (AGP) or even through coughing, sneezing or speaking;and that these forms of transmission are capable of remaining floating for prolonged periods of time in closed spaces. Although the N95 are indicated for the care of patients diagnosed or suspected of COVID-19 because they offer greater protection against aerosols, they are not always available due to their scarcity derived from their high consumption worldwide. In this review the most appropriate alternatives for the shortage crisis are analyzed, trying to prioritize those who have access to materials with filtering efficiency and face sealing to avoid leaks. The appearance of new and more contagious varieties of the virus should obligate all health care workers to always use respirators or medical face masks with greater efficiency within the hospital environment and not only during aerosol generating procedures.

Recommendations for the provision of palliative care to people with COVID-19

The pandemic of SARS-CoV-2 infection, which causes COVID-19, has deeply affected health systems and has had a significant impact on families, communities and nations. A comprehensive response strategy requires in addition to epidemiological, scientific and technical considerations, for human suffering associated with disease, vulnerability and death not to be forgotten. Palliative care for people with suspicion or diagnosis of COVID-19 with serious evolution and their families should also be a key pad of organized actions that helps alleviate suffering and improve quality of life by controlling symptoms, addressing psychological, social and spiritual needs, support for advanced care and its goals, end-of-life care, as well as support in complex decision-making and ethical problems, among others. Recommendations are provided for offering palliative care in the COVID-19 pandemic context.

REGISTRI: Regorafenib in first-line of KIT/PDGFR wild type advanced GIST: Capatalize the A Spanish (GEIS), Italian (ISG) and French Sarcoma Group (FSG) phase II trial

Background: Around 15% of adult GIST are wild type for KIT/PDGFRA mutations (KPWT), usually have SDH deficiencies, and are resistant to imatinib (IM). The underlying mechanisms include overexpression of HIF1α in SDH deficient-GIST, high IGFR signaling through MAPK, BRAF mutation or STAT3 activation. Regorafenib (RE), targeting these pathways, could be more active as upfront therapy in KPWT GIST. Methods: Patients (pts) >18, with advanced non pretreated KPWT GIST were eligible after central confirmation by next-generation sequencing (NGS). Eligible pts received RE at 160mg/d for 21/28d cycles. Primary end-point was disease control rate (DCR) at 12 weeks (RECIST 1.1 ) by central radiological assessment (CRA). Secondary objectives were PFS, OS, ORR (RECIST,Choi), safety and QoL. An amendment allowed previous IM (adjuvant). Statistical assumptions [H0 73% and H1 90% (α 0.1 and β 0.2)], defined a sample size of 20 pts. Results: From May 2016 to October 2020, 30pts with KPWT GIST (by Sanger) underwent central molecular screening. Among the 15 non-eligible pts, 8 harbored KIT exon 11 mutations, 3 exon 9 and 3 PDGFRA exon 18 by NGS. The remaining 16 (53.3%) molecularly eligible pts were enrolled and started RE except one pt due to COVID-19 pandemic. The trial was prematurely closed due to low recruitment, especially after COVID outbreak. Demographics and treatment details in the table. Based on CRA, 12w-DCR was 86.7%. With a median (m) FU of 26 (5-44) months (mo), 10/15 pts progressed, with a mPFS of 10.8 mo (95% CI 6.9-14.8). 6 mo, 9 mo and 12 mo PFS rates were 65%, 48% and 29% respectively. 2 pts were PD-free at 25 and 43 mo from start of RE. 6/15 pts died, with a mOS of 33.5 mo (95% CI NR). [Formula presented] Conclusions: The study results approach the prespecified activity threshold. The low recruitment rate could have affected this attainment. Other analysis of secondary endpoints are ongoing. The high percentage of overlooked mutant GIST by Sanger raises the need of NGS in presumed KPWT GIST. Clinical trial identification: NCT02638766. Legal entity responsible for the study: Spanish Group for Research on Sarcoma (GEIS). Funding: Bayer. Disclosure: J. Martin Broto: Financial Interests, Personal, Expert Testimony, Honoraria: Lilly;Financial Interests, Personal, Expert Testimony, Honoraria: PharmaMar;Financial Interests, Personal, Expert Testimony, Honoraria: Eisai;Financial Interests, Personal, Expert Testimony, Honoraria: Bayer;Financial Interests, Personal, Invited Speaker: PharmaMar;Financial Interests, Institutional, Invited Speaker: PharmaMar;Financial Interests, Institutional, Invited Speaker: Eisai;Financial Interests, Institutional, Invited Speaker: Novartis;Financial Interests, Institutional, Invited Speaker: IMMIX Biopharma;Financial Interests, Institutional, Invited Speaker: Lixte;Financial Interests, Institutional, Invited Speaker: Karyopharm;Financial Interests, Institutional, Invited Speaker: Bayer;Financial Interests, Institutional, Invited Speaker: Celgene;Financial Interests, Institutional, Invited Speaker: Pfizer;Financial Interests, Institutional, Invited Speaker: BMS;Financial Interests, Institutional, Invited Speaker: Blueprint;Financial Interests, Institutional, Invited Speaker: Deciphera;Financial Interests, Institutional, Invited Speaker: Nektar;Financial Interests, Institutional, Invited Speaker: FORMA;Financial Interests, Institutional, Invited Speaker: Amgen;Financial Interests, Institutional, Invited Speaker: Daiichi Sankyo;Financial Interests, Institutional, Invited Speaker: Lilly;Financial Interests, Institutional, Invited Speaker: AROG;Financial Interests, Institutional, Invited Speaker: Adaptimmune;Financial Interests, Institutional, Invited Speaker: GSK. N. Hindi: Financial Interests, Personal, Invited Speaker: PharmaMar;Financial Interests, Personal, Advisory Board: PharmaMar;Financial Interests, Institutional, Research Grant: PharmaMar;Financial Interests, Institutional, Sponsor/Funding: PharmaMar;Financial Interests, Institutional, Research Grant: Nova tis;Financial Interests, Institutional, Research Grant: Eisai;Financial Interests, Institutional, Research Grant: Immix Bio;Financial Interests, Institutional, Sponsor/Funding: Bayer;Financial Interests, Institutional, Sponsor/Funding: Deciphera;Financial Interests, Institutional, Sponsor/Funding: Daychii;Financial Interests, Institutional, Sponsor/Funding: Blueprint;Financial Interests, Institutional, Sponsor/Funding: Adaptimmune;Financial Interests, Institutional, Sponsor/Funding: GSK;Financial Interests, Institutional, Sponsor/Funding: Karyopharm;Financial Interests, Institutional, Sponsor/Funding: Celgene;Financial Interests, Institutional, Sponsor/Funding: AROG. J. Lavernia: Financial Interests, Personal, Invited Speaker: PharmaMar;Financial Interests, Personal, Invited Speaker: BMS. C. Serrano: Financial Interests, Personal, Invited Speaker: Bayer;Financial Interests, Institutional, Research Grant: Bayer. D. Moura: Financial Interests, Institutional, Research Grant: Novartis;Financial Interests, Institutional, Research Grant: Eisai;Financial Interests, Institutional, Research Grant: PharmaMar;Financial Interests, Institutional, Research Grant: Immix Bio. J. Blay: Financial Interests, Institutional, Research Grant: Bayer;Financial Interests, Personal, Invited Speaker: Bayer;Financial Interests, Institutional, Research Grant: Novartis;Financial Interests, Personal, Invited Speaker: Novartis;Financial Interests, Institutional, Research Grant: Roche;Financial Interests, Personal, Invited Speaker: Roche;Financial Interests, Institutional, Research Grant: Deciphera;Financial Interests, Personal, Research Grant: Deciphera. E.R. Fumagalli: Financial Interests, Institutional, Research Grant: Bayer. All other authors have declared no conflicts of interest.

The importance of nonmedical face masks in the general population during the COVID-19 pandemic. A narrative review

The COVID-19 pandemic is a new and great challenge that medicine has had to face. Scientific evidence is growing rapidly and one of the aspects that has generated controversy is the role that the use of non-medical face masks can play when trying to stop the dissemination of cases. This narrative review examines the possible transmission mechanisms of the SARS-COV-2 virus, making emphasis on the role of aerosols, the history of their use inside and outside the hospital environment, the mechanisms by which they offer protection, as well as the efficiency in laboratory test where it is shown that face mask made with several layers of hybrid materials are more effective, and the beneficial impact that they have demonstrated in the general population. Evidence shows its widespread use helps reduce infection by decreasing the transmission of infectious droplets and aerosols, emphasizing that these results are superior when its use is more generalized. Given that it’s impossible to provide the entire population with a medical face mask, public policies should be implemented in order to ensure the generalized use of non-medical face masks, along with hygiene strategies, social distance, avoiding closed places and contact tracking.

Acquired nosocomial SARS-CoV-2 vs. COVID-19: Study in a pediatric hospital of tertiary level hospital care

Background: Nosocomial infection by severe acute respiratory syndrome coronavirus (SARS-CoV-2) has been reported mainly in adult units. Objective(s): To present a report of pediatric cases with nosocomial infection by SARS-CoV-2. Material(s) and Method(s): Patients with nosocomial infection by SARS-Cov-2 vs. COVID-19, confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR), admitted to the Children's Hospital of Mexico. Result(s): Of a total of 163 patients analyzed, only 9 (5.5%) acquired SARS-CoV-2 during their hospital stay. Five were male (55.5%) and 4 (44.4%) females, predominantly adolescents (4 [44.4%]), all older than 17 years. Only one developed multisystem inflammatory syndrome. We analyzed 18 clinical data, of which the most frequent symptom was fever, followed by hyporexia and abdominal pain. Discussion(s): Nosocomial SARS-CoV-2 infection in pediatrics will be reported more often. Conclusion(s): It is necessary to have a more homogeneous definition regarding SARS-CoV-2 vs. nosocomial COVID-19. Copyright © 2022 Elsevier Doyma. All rights reserved.