ABSTRACT
The end of the pandemic could be marked, not by the total eradication of the virus but by a decrease in cases and seasonal peaks in the frequency of SARSCoV-2. Although this has already happened with the influenza A (H1N1) pdm09 virus responsible for the 2009 pandemic, unlike on that occasion, many of the countries that have widely covered their population with the vaccination scheme, still receive the onslaught of COVID-19 and have resumed containment measures due to the appearance, above all, of new variants. The latter suggests that the path to SARS-CoV-2 seasonality may not be as benevolent as the 2009 influenza virus was. Therefore, it is necessary to study the characteristics by which this new virus can acquire seasonality. to consider this scenario and take the necessary measures to face it from a different perspective. © 2022 Academia Nacional de Medicina. All rights reserved.
ABSTRACT
Introduction: The idea of competitive exclusion is undisputed when it comes to animals and bacteria trying to occupy the same ecological niche, but its application to viral coinfection is not so simple to interpret. Viral interference is a phenomenon in which one virus competitively suppresses the replication of other co-infecting viruses and is the most common outcome of viral co-infections. Objective: To better understand the behavior of concomitant respiratory infections in community outbreak settings and individually in hospital settings and individuals with comorbidities. Methods: A search for information was performed in the MEDLINE / PubMed, SciELO and LILACS databases. Articles published in the preprint repository medRxiv and reports from the US Centers for Disease Control and Prevention were also considered. Using the Mendeley reference manager, duplicates and those that did not fit the study objective were eliminated, selecting 48 articles for the review. Analysis and synthesis of information: Evidence supporting viral competitive exclusion between related viruses sharing susceptible and permissive cells was found in the scientific literature. Conclusion: Competitive exclusion prevents two viruses that share similar transmission routes and the same target organ from infecting not only at the same time, but also from spreading successfully. Therefore, syndemia produced by viruses sharing these characteristics could be an unlikely event.
ABSTRACT
The current Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic has severely impacted the economy and health care system in more than 180 countries around the world in an unprecedented event, which since its inception has resulted in countless case reports focusing on the potentially fatal systemic and respiratory manifestations of the disease. However, the full extent of possible neurological manifestations caused by this new virus is not yet known. Understanding the interaction of SARS-CoV-2 with the nervous system is essential to assessing likely short- and long-term pathologic consequences. This review seeks to gather and discuss evidence on the occurrence of neurological manifestations and/or nervous system involvement in SARS-CoV-2 infected patients.
ABSTRACT
Background: The genetic variability of SARS-CoV-2 has increased notably since the pandemic was declared, which has allowed it to represent a continuous challenge for health policies aimed at its control. Objective. Describe the genomic nomenclature used for general and scientific communication about SARS-CoV-2, as well as describe the mutations, evolution, origin and variants of the virus. Material and Methods. A narrative literature review was carried out, for which a search and analysis of the information was carried out until December 15, 2021. 74 sources selected from the MEDLINE / PubMed, SciELO, LILACS databases and official web pages were reviewed;no language restrictions. Results. Mutations are changes in the nucleotide sequence of the viral genome, which, by affecting the epidemiological dynamics in a population, give rise to variants, and these in turn to differentiated clades. Among the variants of interest, Lambda and Mu stand out, identified for the first time in Peru and Colombia, respectively. While, the variants of concern, in chronological order, are Alpha (British), Beta (South African), Gamma (Brazilian), Delta (Indian) and recently Ómicron. Conclusions. It is concluded that the genomic diversity of SARS-CoV-2 is due to its high rate of mutations that can constitute variants and clades. A better understanding of this diversity allows more effective control measures to be taken, guiding the development and use of vaccines, therapies, diagnostics and health policies. © The Author(s), 2021.