Low antiviral resistance in Influenza A and B viruses isolated in Mexico from 2010 to 2023.

The most widely used class of antivirals available for Influenza treatment are the neuraminidase inhibitors (NAI) Oseltamivir and Zanamivir. However, amino acid (AA) substitutions in the neuraminidase may cause reduced inhibition or high antiviral resistance. In Mexico, the current state of knowledge about NAI susceptibility is scarce, in this study we report the results of 14 years of Influenza surveillance by phenotypic and genotypic methods. A total of 255 isolates were assessed with the NAI assay, including Influenza A(H1N1)pdm09, A(H3N2) and Influenza B (IBV). Furthermore, 827 sequences contained in the GISAID platform were analyzed in search of relevant mutations.Overall, five isolates showed highly reduced inhibition or reduced inhibition to Oseltamivir, and two showed reduced inhibition to Zanamivir in the NAI assays. Additionally, five A(H1N1)pdm09 sequences from the GISAID possessed AA substitutions associated to reduced inhibition to Oseltamivir and none to Zanamivir. Oseltamivir resistant A(H1N1)pdm09 harbored the H275Y mutation. No genetic mutations were identified in Influenza A(H3N2) and IBV. Overall, these results show that in Mexico the rate of NAI resistance is low (0.6%), but it is essential to continue the Influenza surveillance in order to understand the drug susceptibility of circulating strains.

Risk factors associated with COVID-19 mortality in Mexico.

BACKGROUND: On December 31, 2019, one of the most serious pandemics in recent times made its appearance. Certain health conditions, such as obesity and diabetes mellitus, have been described to be related to COVID-19 unfavorable outcomes. OBJECTIVE: To identify factors associated with mortality in patients with COVID-19. MATERIAL AND METHODS: Retrospective cohort of 998,639 patients. Patient sociodemographic and clinical characteristics were analyzed, with survivors being compared with the deceased individuals. Cox proportional hazards model was used to identify variables predictive of COVID-19-associated mortality. RESULTS: Among the deceased patients, men accounted for 64.3%, and women, for 35.7%, with the difference being statistically significant. Subjects older than 80 years had a 13-fold higher risk of dying from COVID-19 (95% CI = 12,469, 13,586), while chronic kidney disease entailed a risk 1.5 times higher (95% CI = 1,341, 1,798), and diabetes mellitus involved a risk 1.25 times higher (95% CI = 1.238,1.276). CONCLUSIONS: Age, sex, diabetes mellitus and obesity were found to be predictors of COVID-19 mortality. Further research related to chronic obstructive pulmonary disease, cardiovascular diseases, smoking and pregnancy is suggested.

ANTECEDENTES: El 31 de diciembre de 2019, se inició una de las pandemias más graves de los últimos tiempos. Se ha descrito que ciertas condiciones de salud, como la obesidad y la diabetes mellitus, están relacionadas con desenlaces desfavorables por COVID-19. OBJETIVO: Identificar factores asociados a mortalidad en pacientes con COVID-19. MATERIAL Y MÉTODOS: Cohorte retrospectiva de 998 639 pacientes. Se analizaron las características sociodemográficas y clínicas de los pacientes, y se compararon supervivientes con fallecidos. Se utilizó el modelo de riesgos proporcionales de Cox para la identificación de variables predictivas de defunción por COVID-19. RESULTADOS: Entre los fallecidos, los hombres representaron 64.3 % y las mujeres 35.7 %, diferencia que resultó estadísticamente significativa. Las personas con más de 80 años presentaron un riesgo 13 veces mayor de morir por COVID-19 (IC 95 % = 12.469,13.586) y la enfermedad renal crónica, un riesgo de 1.5 (IC 95 % = 1.341, 1.798); la diabetes mellitus tuvo un riesgo de 1.25 (IC 95 % = 1.238,1.276). CONCLUSIONES: La edad, el sexo, la diabetes mellitus y la obesidad resultaron ser entidades predictivas de muerte por COVID-19. Se sugiere más investigación relacionada con enfermedad pulmonar obstructiva crónica, enfermedades cardiovasculares, tabaquismo y embarazo.

Factores de riesgo asociados a mortalidad por COVID-19 en México / Risk factors associated with COVID-19 mortality in Mexico

Resumen Antecedentes: El 31 de diciembre de 2019, se inició una de las pandemias más graves de los últimos tiempos. Se ha descrito que ciertas condiciones de salud, como la obesidad y la diabetes mellitus, están relacionadas con desenlaces desfavorables por COVID-19. Objetivo: Identificar factores asociados a mortalidad en pacientes con COVID-19. Material y métodos: Cohorte retrospectiva de 998 639 pacientes. Se analizaron las características sociodemográficas y clínicas de los pacientes, y se compararon supervivientes con fallecidos. Se utilizó el modelo de riesgos proporcionales de Cox para la identificación de variables predictivas de defunción por COVID-19. Resultados: Entre los fallecidos, los hombres representaron 64.3 % y las mujeres 35.7 %, diferencia que resultó estadísticamente significativa. Las personas con más de 80 años presentaron un riesgo 13 veces mayor de morir por COVID-19 (IC 95 % = 12.469,13.586) y la enfermedad renal crónica, un riesgo de 1.5 (IC 95 % = 1.341, 1.798); la diabetes mellitus tuvo un riesgo de 1.25 (IC 95 % = 1.238,1.276). Conclusiones: La edad, el sexo, la diabetes mellitus y la obesidad resultaron ser entidades predictivas de muerte por COVID-19. Se sugiere más investigación relacionada con enfermedad pulmonar obstructiva crónica, enfermedades cardiovasculares, tabaquismo y embarazo.

Abstract Background: On December 31, 2019, one of the most serious pandemics in recent times made its appearance. Certain health conditions, such as obesity and diabetes mellitus, have been described to be related to COVID-19 unfavorable outcomes. Objective: To identify factors associated with mortality in patients with COVID-19. Material and methods: Retrospective cohort of 998,639 patients. Patient sociodemographic and clinical characteristics were analyzed, with survivors being compared with the deceased individuals. Cox proportional hazards model was used to identify variables predictive of COVID-19-associated mortality. Results: Among the deceased patients, men accounted for 64.3%, and women, for 35.7%, with the difference being statistically significant. Subjects older than 80 years had a 13-fold higher risk of dying from COVID-19 (95% CI = 12,469, 13,586), while chronic kidney disease entailed a risk 1.5 times higher (95% CI = 1,341, 1,798), and diabetes mellitus involved a risk 1.25 times higher (95% CI = 1.238,1.276). Conclusions: Age, sex, diabetes mellitus and obesity were found to be predictors of COVID-19 mortality. Further research related to chronic obstructive pulmonary disease, cardiovascular diseases, smoking and pregnancy is suggested.

Clinical and Epidemiologic Characteristics of Infants Hospitalized with Respiratory Syncytial Virus Infection During the 2022-2023 Season in Mexico.

In 2022, several countries reported an increase in respiratory syncytial virus (RSV) infections. We assessed the clinical characteristics and outcomes of infants hospitalized with RSV and compared them with infants hospitalized between 2009 and 2015. No significant differences in underlying disorders, intensive care unit admission rates and mortality were observed suggesting currently circulating RSV strains do not show heightened virulence.

Prevalence of respiratory virus in symptomatic children in private physician office settings in five communities of the state of Veracruz, Mexico.

BACKGROUND: Acute respiratory tract infections are the leading cause of morbidity and mortality in children worldwide. Many studies have described the frequency of viruses in hospitalized patients, but studies describing the prevalence of viruses in the community setting are limited, particularly in developing countries, where most of the deaths from serious respiratory diseases occur. The aim of this study was to evaluate the diversity of respiratory viruses in the community setting using molecular diagnostic tools, as well as the clinical characteristics of respiratory viral infections in the general pediatric practice in Mexico. METHODS: Children with respiratory tract infections attending private pediatric practices during a 10-month period in five cities of the state of Veracruz were included. Nasal swabs were taken and processed by a multiplex detection kit for 15 respiratory viruses. RESULTS: 525 children were included from July 2011 to May 2012; 44% were female, mean age was 45 months. The 3 most frequent clinical diagnosis were: rhinopharyngitis 68%, pharyngitis 18%, and 3.3% influenza-like illness. 71.5% of the samples were positive for virus. The five most frequent pathogens were respiratory syncycitial virus in 18.3% of the children, rhinovirus in 17.5%, influenza A 9.1%, adenovirus 7.2%, and enterovirus 3.4%, although all 15 viruses were detected; there were viral coinfections in 14.1%, and 28.5% of the samples were negative. CONCLUSIONS: A large proportion of respiratory infections in the community setting in Mexico was associated to viruses. Although testing for common respiratory pathogens in children with acute respiratory tract infections may lead to a better understanding of the role of viral pathogens in, and eventually to improvement in the management of, individual patients, additional prospective studies are required to study the need of routinely using such tests in general pediatric practices in resource-limited countries.

A correlation of measles specific antibodies and the number of plasmacytoid dendritic cells is observed after measles vaccination in 9 month old infants.

Measles virus (MeV) represents one of the main causes of death among young children, particularly in developing countries. Upon infection, MeV controls both interferon induction (IFN) and the interferon signaling pathway which results in a severe host immunosuppression that can persists for up to 6 mo after infection. Despite the global biology of MeV infection is well studied, the role of the plasmacytoid dendritic cells (pDCs) during the host innate immune response after measles vaccination remains largely uncharacterized. Here we investigated the role of pDCs, the major producers of interferon in response to viral infections, in the development of adaptive immune response against MeV vaccine. We report that there is a strong correlation between pDCs population and the humoral immune response to Edmonston Zagreb (EZ) measles vaccination in 9-month-old mexican infants. Five infants were further evaluated after vaccination, showing a clear increase in pDCs at baseline, one week and 3 months after immunization. Three months postvaccination they showed increase in memory T-cells and pDCs populations, high induction of adaptive immunity and also observed a correlation between pDCs number and the humoral immune response. These findings suggest that the development and magnitude of the adaptive immune response following measles immunization is directly dependent on the number of pDCs of the innate immune response.

PhyloFlu, a DNA microarray for determining the phylogenetic origin of influenza A virus gene segments and the genomic fingerprint of viral strains.

Recent evidence suggests that most influenza A virus gene segments can contribute to the pathogenicity of the virus. In this regard, the hemagglutinin (HA) subtype of the circulating strains has been closely surveyed, but the reassortment of internal gene segments is usually not monitored as a potential source of an increased pathogenicity. In this work, an oligonucleotide DNA microarray (PhyloFlu) designed to determine the phylogenetic origins of the eight segments of the influenza virus genome was constructed and validated. Clades were defined for each segment and also for the 16 HA and 9 neuraminidase (NA) subtypes. Viral genetic material was amplified by reverse transcription-PCR (RT-PCR) with primers specific to the conserved 5' and 3' ends of the influenza A virus genes, followed by PCR amplification with random primers and Cy3 labeling. The microarray unambiguously determined the clades for all eight influenza virus genes in 74% (28/38) of the samples. The microarray was validated with reference strains from different animal origins, as well as from human, swine, and avian viruses from field or clinical samples. In most cases, the phylogenetic clade of each segment defined its animal host of origin. The genomic fingerprint deduced by the combined information of the individual clades allowed for the determination of the time and place that strains with the same genomic pattern were previously reported. PhyloFlu is useful for characterizing and surveying the genetic diversity and variation of animal viruses circulating in different environmental niches and for obtaining a more detailed surveillance and follow up of reassortant events that can potentially modify virus pathogenicity.