Intermunicipal travel networks of Mexico during the COVID-19 pandemic.

Human mobility networks are widely used for diverse studies in geography, sociology, and economics. In these networks, nodes usually represent places or regions and links refer to movement between them. They become essential when studying the spread of a virus, the planning of transit, or society's local and global structures. Therefore, the construction and analysis of human mobility networks are crucial for a vast number of real-life applications. This work presents a collection of networks that describe the human travel patterns between municipalities in Mexico in the 2020-2021 period. Using anonymized mobile location data, we constructed directed, weighted networks representing the volume of travels between municipalities. We analysed changes in global, local, and mesoscale network features. We observe that changes in these features are associated with factors such as COVID-19 restrictions and population size. In general, the implementation of restrictions at the start of the COVID-19 pandemic in early 2020, induced more intense changes in network features than later events, which had a less notable impact in network features. These networks will result very useful for researchers and decision-makers in the areas of transportation, infrastructure planning, epidemic control and network science at large.

SARS-CoV-2 in Mexico: An Association Among Geography, Comorbidities, and Vitamin D Deficiency.

Objective: The aim of this study was to determine the association among temperature, relative humidity, latitude, vitamin D content and comorbidities in the spread of SAR-CoV-2 in Mexico in 2 different waves. Methods: The data on SARS-CoV-2 infections and comorbidities were obtained from the Mexican entities with the highest number of positive cases and deaths in the 2 waves that have most damaged the population. Results: Low temperature, high relative humidity, vitamin D deficiency and high percentage of comorbidities were factors that correlated with a high spread of SARS-CoV-2. Interestingly, 73.8% of the population had one of the most common comorbidities that favor the spread of the virus. Conclusion: The high percentage of comorbidities and the deficient concentration of vitamin D were determining factors in the high number of infections and deaths in Mexico. Furthermore, weather conditions could contribute to and alert to the spread of SARS-CoV-2.

Mental health and adherence to antiretroviral therapy among Mexican people living with HIV during the COVID-19 pandemic.

BACKGROUND: The mental health and medical follow-up of people living with HIV (PLWH) have been disrupted by the COVID-19 pandemic. The objectives of this study were to assess anxiety, depression and substance use in Mexican PLWH during the pandemic; to explore the association of these symptoms with adherence to antiretroviral therapy (ART), and to compare patients with and without vulnerability factors (low socioeconomic level, previous psychological and/or psychiatric treatment). METHODS: We studied 1259 participants in a cross-sectional study, PLWH receiving care at the HIV clinic in Mexico City were contacted by telephone and invited to participate in the study. We included PLWH were receiving ART; answered a structured interview on sociodemographic data and adherence to ART; and completed the psychological instruments to assess depressive and anxiety symptoms and substance use risk. Data collection was performed from June 2020 to October 2021. RESULTS: 84.7% were men, 8% had inadequate ART adherence, 11% had moderate-severe symptoms of depression, and 13% had moderate-severe symptoms of anxiety. Adherence was related to psychological symptoms (p < 0.001). Vulnerable patients were more likely to be women, with low educational level and unemployed (p < 0.001). CONCLUSIONS: It is important to address mental health of PLWH during the COVID-19 pandemic, with special attention to the most vulnerable individuals. Future studies are needed to understand the relationship between mental health and ART adherence.

Molecular transition of SARS-CoV-2 from critical patients during the first year of the COVID-19 pandemic in Mexico City.

Background: The SARS-CoV-2 virus has caused unprecedented mortality since its emergence in late 2019. The continuous evolution of the viral genome through the concerted action of mutational forces has produced distinct variants that became dominant, challenging human immunity and vaccine development. Aim and methods: In this work, through an integrative genomic approach, we describe the molecular transition of SARS-CoV-2 by analyzing the viral whole genome sequences from 50 critical COVID-19 patients recruited during the first year of the pandemic in Mexico City. Results: Our results revealed differential levels of the evolutionary forces across the genome and specific mutational processes that have shaped the first two epidemiological waves of the pandemic in Mexico. Through phylogenetic analyses, we observed a genomic transition in the circulating SARS-CoV-2 genomes from several lineages prevalent in the first wave to a dominance of the B.1.1.519 variant (defined by T478K, P681H, and T732A mutations in the spike protein) in the second wave. Conclusion: This work contributes to a better understanding of the evolutionary dynamics and selective pressures that act at the genomic level, the prediction of more accurate variants of clinical significance, and a better comprehension of the molecular mechanisms driving the evolution of SARS-CoV-2 to improve vaccine and drug development.

Cost-effectiveness and economic investment to eliminate chronic hepatitis C in Mexico.

In July 2020, the Mexican Government initiated the National Program for Elimination of Hepatitis C (HCV) under a procurement agreement, securing universal, free access to HCV screening, diagnosis and treatment for 2020-2022. This analysis quantifies the clinical and economic burden of HCV (MXN) under a continuation (or end) to the agreement. A modelling and Delphi approach was used to evaluate the disease burden (2020-2030) and economic impact (2020-2035) of the Historical Base compared to Elimination, assuming the agreement continues (Elimination-Agreement to 2035) or terminates (Elimination-Agreement to 2022). We estimated cumulative costs and the per-patient treatment expenditure needed to achieve net-zero cost (the difference in cumulative costs between the scenario and the base). Elimination is defined as a 90% reduction in new infections, 90% diagnosis coverage, 80% treatment coverage and 65% reduction in mortality by 2030. A viraemic prevalence of 0.55% (0.50-0.60) was estimated on 1st January 2021, corresponding to 745,000 (95% CI 677,000-812,000) viraemic infections in Mexico. The Elimination-Agreement to 2035 would achieve net-zero cost by 2023 and accrue 31.2 billion in cumulative costs. Cumulative costs under the Elimination-Agreement to 2022 are estimated at 74.2 billion. Under Elimination-Agreement to 2022, the per-patient treatment price must decrease to 11,000 to achieve net-zero cost by 2035. The Mexican Government could extend the agreement through 2035 or reduce the cost of HCV treatment to 11,000 to achieve HCV elimination at net-zero cost.

Vaccine hesitancy and the willingness to recommend the COVID-19 vaccine to children in a rural country on the United States-Mexico border.

Introduction: As of October 26, 2022, only 9% of children in the United States aged 6 months to 4 years have received at least one dose of COVID-19 vaccine despite FDA approval since June 17, 2022. Rates are better yet still low for children aged 5 to 11 years as nearly 30% were fully vaccinated as of August 23, 2022. Vaccine hesitancy among adults is one of the major factors affecting low vaccine uptake rates in children against COVID-19, yet most studies examining vaccine hesitancy have targeted school-age and adolescent children. Methods: With the aim of assessing the willingness to recommend the COVID-19 vaccination to children under 5 years compared to children 5 to 12 years of age, a county-wide survey was conducted between January 11 and March 7, 2022, among adults on the United States-Mexico border. Results: Among the 765 responses, 72.5% were female and 42.3% were Latinx. The most significant factor associated with likelihood to recommend the COVID-19 vaccine to children less than 5 years and 5-12 years of age was adult vaccination status. Ordinal logistic regression also indicated that ethnicity, primary language, being a parent, previous COVID-19 infection, and concern about getting COVID-19 in the future were significantly associated with likelihood of COVID-19 vaccine recommendation to children < 5 years and 5-12 years old. Discussion: This study found high consistency among respondents in their willingness to vaccinate children aged < 5 years compared with children aged 5-12 years. Our findings support public health strategies that target adult vaccinations as an avenue to improve childhood vaccinations for young children.

Alcohol and cannabis use in traffic-related injuries in Mexico City.

BACTERKGROUND: There is debate on whether cannabis affects road traffic injuries (RTIs) separately from the effects of alcohol. Our goals are to report the possible increase in risk of an RTI among alcohol and cannabis users by type of exposure (biological, self-reported and combined) and the possible interaction of alcohol and cannabis in patients with an RTI in an emergency department in Mexico City. METHODS: A case-crossover study with 433 cases of RTI (as a pedestrian, driver or passenger) during the period January-April 2022. A breath sample, an oral sample for cannabis detection and self-reported alcohol and cannabis use 6 hours prior to the RTI and in two control periods were used. We report ORs and 95% CIs from conditional logistic regressions for the case-crossover estimates. RESULTS: Alcohol alone increased the risk of an RTI (OR=6.02, 95% CI 3.29 to 10.99) for most RTIs, regardless of whether we used information from self-reports or a breath sample in the hazard period. Conversely, cannabis only increased the RTI when we added information in the hazard period from self-reports or oral samples. Nevertheless, this increase in risk disappeared (OR=2.06, 95% CI 0.90 to 4.70) among those who only used cannabis. We also found no evidence of interaction between alcohol and cannabis in the risk of an RTI. CONCLUSIONS: Alcohol is the most commonly used substance in Mexico and a high-risk factor for RTI in Mexico City. Although cannabis alone was not associated with an RTI, continuous monitoring of its effects is required.

[Geographical variation of asthma prevalence among Mexican children during the COVID-19 pandemic]. / Variación geográfica en la prevalencia de asma en niños mexicanos durante la pandemia de la COVID-19.

OBJECTIVE: The purpose of this study was to analyze the geographic variation in the prevalence of asthma in children, according to their place of residence in Mexico. METHODS: A cross-sectional analysis of the epidemiological surveillance system dataset for respiratory diseases in Mexico carried on. From 27 February to 5 November 2020, a total of 1,048,576 subjects were screened for SARS-CoV2 infection, of which 35,899 were children under 18 years of age. The strength of the association was estimated by odds ratio (OR). RESULTS: Of 1,048,576 patients who attended for SARS-CoV2 infection detection, 35,899 corresponded to pediatric patients who met the study criteria. The estimated national prevalence of asthma was 3.9% (95% CI: 3.7-4.1%). The nationwide prevalence of asthma was 3.9% (95% CI: 3.7% - 4.1%); the minimum was 2.8% (Southeast region) and the maximum 6.8% (Southeast region). Compared to the South-West Region that presented the minimum prevalence at the national level, the Northwest (OR = 2.41) and Southeast (OR = 1.33) regions showed the highest risk of asthma in pediatric population. CONCLUSIONS: The prevalence of asthma in children differed markedly among the different regions of Mexico; two regions, Northwest and Southeast, stood out. This study puts into context the role of the environment on the prevalence of asthma in children.

OBJECTIVO: Estimar la prevalencia de asma en pacientes pediátricos, según su lugar de residencia en la República Mexicana, durante la pandemia por SARS-CoV-2. MÉTODOS: Estudio transversal, llevado a cabo a partir de la revisión de datos del Sistema de Vigilancia Epidemiológica para Enfermedades Respiratorias en México, analizados del 27 febrero al 5 de noviembre de 2020. Criterios de inclusión: pacientes que acudieron a la detección de infección por SARS-CoV2, menores de 18 años. La fuerza de asociación se estimó con la razón de momios. RESULTADOS: De 1,048,576 pacientes que acudieron a la detección de infección de SARS-CoV2, 35,899 correspondieron a pacientes pediátricos que cumplieron con los criterios del estudio. La prevalencia nacional de asma estimada fue de 3.9% (IC95%: 3.7-4.1%); la prevalencia mínima se observó en la región Suroeste (2.8%) y la máxima en el Sureste (6.8%); comparada con la región Suroeste, que registró la prevalencia mínima a nivel nacional, y la Noroeste (RM = 2.41) y Sureste (RM = 1.33) mostraron el mayor riesgo de asma en la población pediátrica. CONCLUSIONES: La prevalencia de asma en niños mexicanos difirió notoriamente en los diferentes estados de la República Mexicana; sobresalieron las regiones Noroeste y Sureste. Este estudio pone de manifiesto el papel del medio ambiente en la prevalencia del asma en pacientes pediátricos mexicanos.

Importance of Confirmatory Tests for Sars-Cov-2 Infection in Hemodialysis Patients: A Multicenter Mexican Registry.

Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, patients with chronic kidney disease vulnerable to suffering more severe COVID-19 disease and worse outcomes have been identified. Objectives: Our study's aim was to determine the incidence, characteristics, and outcomes of SARS-CoV-2 infection in patients of hemodialysis (HD) units in Mexico and to describe the availability of confirmatory testing. Methods: This study was multicentric study of 19 HD units, conducted between March 2020 and March 2021. Results: From a total of 5779 patients, 955 (16.5%) cases of suspicious COVID-19 were detected; a SARS-CoV-2 reverse transcription polymerase chain reaction test was done in only 50.6% of patients. Forty-five percentages were hospitalized and 6% required invasive mechanical ventilation (IMV). There was no significant difference in mortality between confirmed (131/483) and suspicious (124/472) cases (p = 0.74). The percentage of patients in need of hospitalization, IMV, and deceased was greater than in the rest of the study population. Conclusions: The study revealed that 49.4% of the cases were not confirmed, a worrisome observation given that this is a highly vulnerable population (higher probability of contagion and worse outcomes), in which 100% of patients should have a confirmatory test.

Prognostic factors of COVID-19 severity and mortality in the Yucatecan ethnic of México contrast with other populations.

INTRODUCTION: Previous studies that identified the prognostic factors for the severity of the new coronavirus disease 2019 (COVID-19) in different populations have generated controversial conclusions. The lack of a standard definition of COVID-19 severity and the differences between clinical diagnoses might make it difficult to provide optimum care according to the characteristics of each population. METHODOLOGY: We investigated the factors that impacted the severe outcome or death from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients treated at the Mexican Institute of Social Security in Yucatán, México in 2020. A cross-sectional study of COVID-19 confirmed cases was done to know the prevalence and association of the demographic and clinical characteristics with a severe or fatal outcome. Information from the National Epidemiological Surveillance System (SINAVE) database was used and SPSS v 21 was used for statistical analyses. We used the World Health Organization (WHO) and the Centers for Diseases Control and Prevention (CDC) symptomatology classifications to define severe cases. RESULTS: Diabetes and pneumonia increased the risk of death and having diabetes was a prognostic factor for severe illness following SARS-CoV-2 infection. CONCLUSIONS: Our results highlight the influence of cultural and ethnic factors, the necessity to standardize the parameters for clinical diagnoses, and to use the same criteria for the definition of COVID-19 severity to establish the clinical conditions that contribute to the pathophysiology of this disease in each population.

Prevalence of symptoms, comorbidities, and reinfections in individuals infected with Wild-Type SARS-CoV-2, Delta, or Omicron variants: a comparative study in western Mexico.

Introduction: The variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been classified into variants of interest (VOIs) or concern (VOCs) to prioritize global monitoring and research on variants with potential risks to public health. The SARS-CoV-2 high-rate mutation can directly impact the clinical disease progression, epidemiological behavior, immune evasion, vaccine efficacy, and transmission rates. Therefore, epidemiological surveillance is crucial for controlling the COVID-19 pandemic. In the present study, we aimed to describe the prevalence of wild-type (WT) SARS-CoV-2 and Delta and Omicron variants in Jalisco State, Mexico, from 2021 to 2022, and evaluate the possible association of these variants with clinical manifestations of COVID-19. Methods: Four thousand and ninety-eight patients diagnosed with COVID-19 by real-time PCR (COVIFLU, Genes2Life, Mexico) from nasopharyngeal samples from January 2021 to January 2022 were included. Variant identification was performed by the RT-qPCR Master Mut Kit (Genes2Life, Mexico). A study population follow-up was performed to identify patients who had experienced reinfection after being vaccinated. Results and Discussion: Samples were grouped into variants according to the identified mutations: 46.3% were Omicron, 27.9% were Delta, and 25.8% were WT. The proportions of dry cough, fatigue, headache, muscle pain, conjunctivitis, fast breathing, diarrhea, anosmia, and dysgeusia were significantly different among the abovementioned groups (p < 0.001). Anosmia and dysgeusia were mainly found in WT-infected patients, while rhinorrhea and sore throat were more prevalent in patients infected with the Omicron variant. For the reinfection follow-up, 836 patients answered, from which 85 cases of reinfection were identified (9.6%); Omicron was the VOC that caused all reported reinfection cases. In this study, we demonstrate that the Omicron variant caused the biggest outbreak in Jalisco during the pandemic from late December 2021 to mid-February 2022 but with a less severe form than the one demonstrated by Delta and WT. The co-analysis of mutations and clinical outcomes is a public health strategy with the potential to infer mutations or variants that could increase disease severity and even be an indicator of long-term sequelae of COVID-19.

Impact of healthcare strain on access to mechanical ventilation and mortality of hospitalized COVID-19 patients: a retrospective cohort study.

OBJECTIVE: Healthcare saturation has been a prominent worry during the COVID-19 pandemic. Increase of hospital beds with mechanical ventilators has been central in Mexico's approach, but it is not known whether this actually improves access to care and the resulting quality of it. This study aimed to determine the impact of healthcare strain and other pre-specified variables on dying from coronavirus disease 2019 (COVID-19) without receiving invasive mechanical ventilation (IMV). METHODS: A retrospective cohort study was conducted using open data from Mexico City between 8 May 2020 and 5 January 2021. We performed Cox proportional hazards models to identify the strength of the association between proposed variables and the outcomes. RESULTS: Of 33 797 hospitalized patients with suspected or confirmed COVID-19, 19 820 (58.6%) did not require IMV and survived, 5414 (16.1%) required IMV and were intubated and 8563 (25.3%) required IMV but died without receiving it. A greater occupation of IMV-capable beds increased the hazard of death without receiving IMV (hazard ratio [HR] 1.56, comparing 90% with 50% occupation). Private healthcare was the most protective factor for death without IMV (HR 0.14). CONCLUSIONS: Higher hospital bed saturation increased the hazard of dying without being intubated and worsened the outcomes among mechanically ventilated patients. Older age also increased the hazard of the outcomes, while private healthcare dramatically decreased them.

Prevalence of Depression, Anxiety, Post-Traumatic Stress, and Insomnia Symptoms Among Frontline Healthcare Workers in a COVID-19 Hospital in Northeast Mexico.

OBJECTIVE: Frontline healthcare workers (FHCWs) exposed to COVID-19 patients are at an increased risk of developing psychological burden. This study aims to determine the prevalence of mental health symptoms and associated factors among Mexican FHCWs attending COVID-19 patients. METHODS: FHCWs, including attending physicians, residents/fellows, and nurses providing care to COVID-19 patients at a private hospital in Monterrey, Mexico, were invited to answer an online survey between August 28, and November 30, 2020. Symptoms of depression, anxiety, post-traumatic stress, and insomnia were evaluated with the Patient Health Questionnaire (PHQ)-9, Generalized Anxiety Disorder (GAD)-7, Impact of Event Scale-Revised (IES-R), and Insomnia Severity Index (ISI). Multivariate analysis was performed to identify variables associated with each outcome. RESULTS: 131 FHCWs, 43.5% attending physicians, 19.8% residents/fellows, and 36.6% nurses were included. The overall prevalence of depression, anxiety, post-traumatic stress, and insomnia was 36%, 21%, 23%, and 24% respectively. Multivariate analysis revealed that residents/fellows and nurses reported more depression and insomnia than attending physicians. Although not significant, residents/fellows were more likely to experience all symptoms than nurses. CONCLUSIONS: Mexican FHCWs, especially nurses and residents/fellows, experienced a significant psychological burden while attending to COVID-19 patients. Tailored interventions providing support to FHCWs during future outbreaks are required.

Country and policy factors influencing the implementation of primary care-based alcohol screening: A comparison of Colombia, Mexico and Peru.

Researchers and practitioners recognise the importance of context when implementing healthcare interventions, but the influence of wider environment is rarely mapped. This paper identifies the country and policy-related factors potentially explaining the country differences in outcomes of an intervention focused on improving detection and management of heavy alcohol use in primary care in Colombia, Mexico and Peru. Qualitative data obtained through interviews, logbooks and document analysis are used to explain quantitative data on number of alcohol screenings and screening providers in each of the countries. Existing alcohol screening standards in Mexico, and policy prioritisation of primary care and consideration of alcohol as a public health issue in Colombia and Mexico positively contributed to the outcome, while the COVID-19 pandemic had a negative impact. In Peru, the context was unsupportive due to a combination of: political instability amongst regional health authorities; lack of focus on strengthening primary care due to the expansion of community mental health centres; alcohol considered as an addiction rather than a public health issue; and the impact of COVID-19 on healthcare. We found that wider environment-related factors interacted with the intervention implemented and can help explain country differences in outcomes.

National data linkage assessment of live births and deaths in Mexico: Estimating under-five mortality rate ratios for vulnerable newborns and trends from 2008 to 2019.

BACKGROUND: Linked datasets that enable longitudinal assessments are scarce in low and middle-income countries. OBJECTIVES: We aimed to assess the linkage of administrative databases of live births and under-five child deaths to explore mortality and trends for preterm, small (SGA) and large for gestational age (LGA) in Mexico. METHODS: We linked individual-level datasets collected by National statistics from 2008 to 2019. Linkage was performed based on agreement on birthday, sex, residential address. We used the Centre for Data and Knowledge Integration for Health software to identify the best candidate pairs based on similarity. Accuracy was assessed by calculating the area under the receiver operating characteristic curve. We evaluated completeness by comparing the number of linked records with reported deaths. We described the percentage of linked records by baseline characteristics to identify potential bias. Using the linked dataset, we calculated mortality rate ratios (RR) in neonatal, infants, and children under-five according to gestational age, birthweight, and size. RESULTS: For the period 2008-2019, a total of 24,955,172 live births and 321,165 under-five deaths were available for linkage. We excluded 1,539,046 records (6.2%) with missing or implausible values. We succesfully linked 231,765 deaths (72.2%: range 57.1% in 2009 and 84.3% in 2011). The rate of neonatal mortality was higher for preterm compared with term (RR 3.83, 95% confidence interval, [CI] 3.78, 3.88) and for SGA compared with appropriate for gestational age (AGA) (RR 1.22 95% CI, 1.19, 1.24). Births at <28 weeks had the highest mortality (RR 35.92, 95% CI, 34.97, 36.88). LGA had no additional risk vs AGA among children under five (RR 0.92, 95% CI, 0.90, 0.93). CONCLUSIONS: We demonstrated the utility of linked data to understand neonatal vulnerability and child mortality. We created a linked dataset that would be a valuable resource for future population-based research.

Ophthalmic manifestations in patients recovered from COVID-19 in Mexico.

INTRODUCTION AND OBJECTIVES: Although the ophthalmic manifestations appear to be associated with the coronavirus disease 2019 (COVID-19), there is not enough evidence. Hence, the aim of this study was to determine the various types and frequency of ophthalmic manifestations in patients recovered from SARS-CoV-2 infection in Mexico. MATERIAL AND METHODS: This retrospective, observational and descriptive study included all patients recovered from SARS-CoV-2 infection attending the tertiary level hospital of Mexican Social Security Institute (IMSS) from June 2020 to June 2022. During the hospital admission of patients, the demographic data such age, name, gender was recorded. Ophthalmologic examination was performed under torchlight by an ophthalmologist in the Department of Ophthalmology from IMSS. Data was compiled and statistically analyzed using Fisher's exact test and Spearman correlation. RESULTS: A total of 3081 SARS-CoV-2-positive patients were recorded, of which 318 (10.32%) met the inclusion criteria. Of them, 21 (6.60%) had ophthalmic manifestations and the female-to-male ratio was 1.6:1. The mean age (±SD) was 47.95±15.27 years and the median (interquartile range) time from the diagnosis of COVID-19, as defined by positive SARS-CoV-2 RT-PCR testing, to detection of the ophthalmic manifestation was 31 (142) days. The most common ocular manifestation was orbital mucormycosis (23.80%). Interestingly, the presence of ophthalmic manifestations was not associated with severe COVID-19 (p=0.665). CONCLUSIONS: The ophthalmic manifestations are infrequent in patients recovered from severe COVID-19. Nevertheless, further large sample studies are needed to confirm these findings.

Guidelines on epidemics in Mexico. Historical perspective.

A perspective of epidemics and pandemics in Mexico is offered, focusing on three time periods, namely, end of the 18th century, the 20th century, and the 21st century, in order to analyze how they were approached by health and government authorities, as well as the challenges they have represented. Historical documentary sources were consulted and, in current cases, participation in them was analyzed. Epidemiological and social historical methodologies were combined. The presence of epidemics in Mexico is a constant on its evolution, which highlights the need for the epidemiological surveillance system to be updated, the importance of being prepared to face an epidemic and to develop a contingency plan.

Se ofrece una perspectiva de las epidemias y pandemias en México en tres periodos: fines del siglo XVIII y siglos XX y XXI, con el fin de analizar cómo las autoridades sanitarias y gubernamentales abordaron estos problemas, así como los desafíos que han representado. Se consultaron fuentes históricas documentales y, en los casos actuales, la participación en ellos. Se combinó metodología epidemiológica e histórica social. La presencia de las epidemias en México es una constante, lo cual evidencia la necesidad de actualizar el sistema de vigilancia epidemiológica, de estar preparados para enfrentar una epidemia y de elaborar un plan de contingencia.

Digital food and beverage marketing appealing to children and adolescents: An emerging challenge in Mexico.

BACKGROUND: Digital food marketing is increasing and has an impact on children's behaviour. Limited research has been performed in Latin America. OBJECTIVES: To determine the extent and nature of Mexican children's and adolescents' exposure to digital food and beverage marketing during recreational internet use. METHODS: A crowdsourcing strategy was used to recruit 347 participants during the COVID-19 lockdown. Participants completed a survey and recorded 45 minutes of their device's screen time using screen-capture software. Food marketing was identified and nutrition information for each marketed product was collected. Healthfulness of products was determined using the Pan-American Health Organization and the Mexican Nutrient Profile Model (NPM). A content analysis was undertaken to assess marketing techniques. RESULTS: Overall, 69.5% of children and adolescents were exposed to digital food marketing. Most frequently marketed foods were ready-made foods. Children and adolescents would typically see a median of 2.7 food marketing exposures per hour, 8 daily exposures during a weekday and 6.7 during a weekend day. We estimated 47.3 food marketing exposures per week (2461 per year). The most used marketing technique was brand characters. Marketing was appealing to children and adolescents yet most of the products were not permitted for marketing to children according to the NPMs (>90%). CONCLUSIONS: Mexican children and adolescents were exposed to unhealthy digital food marketing. The Government should enforce evidence-based mandatory regulations on digital media.

Protection of hybrid immunity against SARS-CoV-2 reinfection and severe COVID-19 during periods of Omicron variant predominance in Mexico.

Background: With the widespread transmission of the Omicron SARS-CoV-2 variant, reinfections have become increasingly common. Here, we explored the role of immunity, primary infection severity, and variant predominance in the risk of reinfection and severe COVID-19 during Omicron predominance in Mexico. Methods: We analyzed reinfections in Mexico in individuals with a primary infection separated by at least 90 days from reinfection using a national surveillance registry of SARS-CoV-2 cases from March 3rd, 2020, to August 13th, 2022. Immunity-generating events included primary infection, partial or complete vaccination, and booster vaccines. Reinfections were matched by age and sex with controls with primary SARS-CoV-2 infection and negative RT-PCR or antigen test at least 90 days after primary infection to explore reinfection and severe disease risk factors. We also compared the protective efficacy of heterologous and homologous vaccine boosters against reinfection. Results: We detected 231,202 SARS-CoV-2 reinfections in Mexico, most occurring in unvaccinated individuals (41.55%). Over 207,623 reinfections occurred during periods of Omicron (89.8%), BA.1 (36.74%), and BA.5 (33.67%) subvariant predominance and a case-fatality rate of 0.22%. Vaccination protected against reinfection, without significant influence of the order of immunity-generating events and provided >90% protection against severe reinfections. Heterologous booster schedules were associated with ~11% and ~ 54% lower risk for reinfection and reinfection-associated severe COVID-19, respectively, modified by time-elapsed since the last immunity-generating event, when compared against complete primary schedules. Conclusion: SARS-CoV-2 reinfections increased during Omicron predominance. Hybrid immunity provides protection against reinfection and associated severe COVID-19, with potential benefit from heterologous booster schedules.