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Background: A 30-second aerosol measles vaccination successfully primes children 12 months of age and older but is poorly immunogenic when given to 9-month-old children. We examined the immune responses when increasing the duration to aerosol exposure in 9-month-olds.Methods: One hundred and thirteen healthy 9-month-old children from Mexico City were enrolled; 58 received aerosol EZ measles vaccine for 2.5 minutes and 55 subcutaneously. Measles-specific neutralizing antibodies and cellular responses were measured before and at 3 and 6 months postimmunization.Results: Adaptive immunity was induced in 97% after aerosol and 98% after subcutaneous administration. Seroconversion rates and GMCs were 95% and 373 mIU/mL (95% confidence interval [CI], 441-843) following aerosol vaccination and 91% and 306 mIU/mL (95% CI, 367-597) after subcutaneous administration at 3 months. The percentage of children with a measles-specific stimulation index ≥3 was 45% and 60% in the aerosol versus 55% and 59% in the subcutaneous group at 3 and 6 months, respectively. CD8 memory cell frequencies were higher in the aerosol group at 3 months compared with the subcutaneous group. Adverse reactions were comparable in both groups.Conclusions: Increasing exposure time to aerosol measles vaccine elicits immune responses that are comparable to those seen when an equivalent dose is administered by the subcutaneous route in 9-month-old infants. [ABSTRACT FROM AUTHOR]

Background: Human rhinovirus (HRV), traditionally recognized as the primary etiological agent of the common cold, has become the second most important viral agent in bronchopulmonary conditions, such as pneumonia and asthma exacerbations. During the COVID-19 pandemic, several viruses exhibited changes in their epidemiological behavior. This study aims to evaluate the clinical and epidemiological characteristics of children with HRV pneumonia before and during the pandemic in Mexico. Methods: A comparative ambispective longitudinal epidemiological study of two cohorts (prepandemic and pandemic periods) was carried out. Two databases were compared: one from 2010 to 2013 and the other from 2021 to 2023. Children under 5 years of age diagnosed with HRV pneumonia were included. Student's t -test, χ 2 tests, and logistic regression were used to assess risk factors associated with severe pneumonia. Incidence density was calculated as HRV cases per 10 new cases of pneumonia per month for each year. Results: During the pandemic, the age of presentation shifted from 5 months to 16 months. There was a higher incidence of HRV pneumonia in children during the pandemic, particularly in the second half of 2021, with a peak in July and August. In addition, there was an increase in severity (53% vs. 63%, p =0.006) and coinfections (51.3% vs. 76% p < 0.001). A higher prevalence of all risk factors was observed in the second cohort. Conclusions: During the pandemic, a shift toward older age, a higher percentage of coinfections, and increased severity associated to HRV pneumonia were observed. These findings highlight the need for the development and implementation of targeted prevention and treatment measures for HRV., Competing Interests: Maria del Carmen Espinosa-Sotero is a member of the Pfizer, Sanofi, and MSD speaker's bureau; Daniel E. Noyola has participated as a member of the AbbVie, Sanofi Pasteur, and AstraZeneca speakers' bureau and served on the advisory board for Sanofi Pasteur, GSK, and Pfizer. Rosa María Wong-Chew is a member of the Seegene, Asofarma, AstraZeneca, and Sanofi Pasteur speaker's bureau and served on the advisory board for Sanofi Pasteur, Asofarma, and AstraZeneca. The rest of the authors declare no conflicts of interest., (Copyright © 2024 Fanny Yasmin Ortega-Vargas et al.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

A balanced microbiota-microorganisms that live in the gut-is crucial in the early years of a child's life, while dysbiosis-altered microbiota-has been linked to the development of various diseases. Probiotics, such as Alkalihalobacillus clausii , are commonly used to restore the balance of gut microbiota and have shown additional antimicrobial and immunomodulatory properties. Intake of micronutrients can affect the structure and function of the gut barrier and of the microbiota by having multiple effects on cellular metabolism (e.g., immunomodulation, gene expression, and support structure proteins). An inadequate zinc intake increases the risk of deficiency and associated immune dysfunctions; it is responsible for an increased risk of developing gastrointestinal diseases, respiratory infections, and stunting. Paediatric zinc deficiency is a public health concern in many countries, especially in low-income areas. Currently, zinc supplementation is used to treat childhood diarrhoea. This review examines how combining A. clausii and zinc could improve dysbiosis, gut health, and immunity. It suggests that this combination could be used to prevent and treat infectious diseases and diarrhoea in children up to adolescence.

Background: SARS-CoV2 induces flu-like symptoms that can rapidly progress to severe acute lung injury and even death. The virus also invades the central nervous system (CNS), causing neuroinflammation and death from central failure. Intravenous (IV) or oral dexamethasone (DXM) reduced 28 d mortality in patients who required supplemental oxygen compared to those who received conventional care alone. Through these routes, DMX fails to reach therapeutic levels in the CNS. In contrast, the intranasal (IN) route produces therapeutic levels of DXM in the CNS, even at low doses, with similar systemic bioavailability., Aims: To compare IN vs. IV DXM treatment in hospitalized patients with COVID-19., Methods: A controlled, multicenter, open-label trial. Patients with COVID-19 (69) were randomly assigned to receive IN-DXM (0.12 mg/kg for three days, followed by 0.6 mg/kg for up to seven days) or IV-DXM (6 mg/d for 10 d). The primary outcome was clinical improvement, as defined by the National Early Warning Score (NEWS) ordinal scale. The secondary outcome was death at 28 d between IV and IN patients. Effects of both treatments on biochemical and immunoinflammatory profiles were also recorded., Results: Initially, no significant differences in clinical severity, biometrics, and immunoinflammatory parameters were found between both groups. The NEWS-2 score was reduced, in 23 IN-DXM treated patients, with no significant variations in the 46 IV-DXM treated ones. Ten IV-DXM-treated patients and only one IN-DXM patient died., Conclusions: IN-DMX reduced NEWS-2 and mortality more efficiently than IV-DXM, suggesting that IN is a more efficient route of DXM administration., Competing Interests: Conflict of Interest The authors have no other relevant affiliations or financial involvement with any organization or entity that has a financial interest in, or financial conflict with, the subject matter or materials discussed in the manuscript, except as stated., (Copyright © 2024. Published by Elsevier Inc.)

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., (Copyright: © 2024 Permanyer.)

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., Competing Interests: D.E.N. has participated as a member of the speakers’ bureau of AbbVie and Astra-Zeneca, speakers’ bureau and advisory board for Sanofi Pasteur and advisory board for Pfizer. R.M.W.-C. has participated as a member of advisory board for Sanofi Pasteur. The other authors have no conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Human respiratory syncytial virus (hRSV) is the leading cause of acute lower respiratory tract infections in children under five years of age and older adults worldwide. During hRSV infection, host cells undergo changes in endomembrane organelles, including mitochondria. This organelle is responsible for energy production in the cell and plays an important role in the antiviral response. The present study focuses on characterizing the ultrastructural and functional changes during hRSV infection using thin-section transmission electron microscopy and RT-qPCR. Here we report that hRSV infection alters mitochondrial morphodynamics by regulating the expression of key genes in the antiviral response process, such as Mfn1, VDAC2, and PINK1. Our results suggest that hRSV alters mitochondrial morphology during infection, producing a mitochondrial phenotype with shortened cristae, swollen matrix, and damaged membrane. We also observed that hRSV infection modulates the expression of the aforementioned genes, possibly as an evasion mechanism in the face of cellular antiviral response. Taken together, these results advance our knowledge of the ultrastructural alterations associated with hRSV infection and might guide future therapeutic efforts to develop effective antiviral drugs for hRSV treatment.

Background: The incidence of postoperative spinal infection (PSI) ranges from 0% to 10%, with devastating effects on the patient prognosis because of higher morbidity while increasing costs to the health care system. PSIs are elusive and difficult to diagnose, especially in the early postoperative state, because of confusing clinical symptoms, rise in serum biomarkers, or imaging studies. Current research on diagnosis has focused on serum biomarkers; nevertheless, most series rely on retrospective cohorts where biomarkers are studied individually and at different time points., Objective: This paper presents the protocol for a systematic review that aims to determine the inflammatory biomarker behavior profile of patients following elective degenerative spine surgery and their differences compared to those coursing with PSIs., Methods: The proposed systematic review will follow the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. This protocol was registered at PROSPERO on January 19, 2022. We will include studies related to biomarkers in adult patients operated on for degenerative spinal diseases and those developing PSIs. The following information will be extracted from the papers: (1) study title; (2) study author; (3) year; (4) evidence level; (5) research type; (6) diagnosis group (elective postoperative degenerative disease or PSI); (7a) region (cervical, thoracic, lumbosacral, and coccygeal); (7b) type of infection by anatomical or radiological site; (8) surgery type (including instrumentation or not); (9) number of cases; (10) mean age or individual age; (11) individual serum biomarker values from the preoperative state up to 90 days postoperative for both groups, including (10a) interleukin-6, (10b) presepsin, (10c) erythrocyte sedimentation rate, (10d) leukocyte count, (10e) neutrophil count, (10f) C-reactive protein, (10g) serum amyloid, (10h) white cell count, (10i) albumin, (10j) prealbumin, (10k) procalcitonin, (10l) retinol-associated protein, and (10m) Dickkopf-1; (11) postoperative days at symptoms or diagnosis; (12) type of organism; (13) day of starting antibiotics; (14) duration of treatment; and (15) any biases (including comorbidities, especially those affecting immunological status). All data on biomarkers will be presented graphically over time., Results: No ethical approval will be required, as this review is based on published data and does not involve interaction with human participants. The search for this systematic review commenced in February 2021, and we expect to publish the findings in mid-2023., Conclusions: This study will provide the behavior profile of biomarkers for PSI and patients following elective surgery for degenerative spinal diseases from the preoperative period up to 90 days postoperative, providing cutoff values on the day of diagnosis. This research will provide clinicians with highly trustable cutoff reference values for PSI diagnosis. Finally, we expect to provide a basis for future research on biomarkers that help diagnose more accurately and in a timely manner in the early stages of illness, ultimately impacting the patient's physical and mental health, and reducing the disease burden., Trial Registration: PROSPERO CRD42022304645; https://www.crd.york.ac.uk/prospero/display&#95;record.php?RecordID=304645., International Registered Report Identifier (irrid): DERR1-10.2196/41555., (©José Alberto Israel Romero Rangel, Fiacro Jiménez Ponce, Rosa Maria Wong Chew, Juan Osvaldo Talavera Piña, Adolfo Martínez Tovar. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 28.04.2023.)

Background: After the initial outbreak in China (December 2019), the World Health Organization declared COVID-19 a pandemic on March 11 th , 2020. This paper aims to describe the first 2 years of the pandemic in Mexico., Design and Methods: This is a population-based longitudinal study. We analyzed data from the national COVID-19 registry to describe the evolution of the pandemic in terms of the number of confirmed cases, hospitalizations, deaths and reported symptoms in relation to health policies and circulating variants. We also carried out logistic regression to investigate the major risk factors for disease severity., Results: From March 2020 to March 2022, the coronavirus disease 2019 (COVID-19) pandemic in Mexico underwent four epidemic waves. Out of 5,702,143 confirmed cases, 680,063 were hospitalized (11.9%), and 324,436 (5.7%) died. Even if there was no difference in susceptibility by gender, males had a higher risk of death (CFP: 7.3 vs. 4.2%) and hospital admission risk (HP: 14.4 vs. 9.5%). Severity increased with age. With respect to younger ages (0-17 years), the 60+ years or older group reached adjusted odds ratios of 9.63 in the case of admission and 53.05 (95% CI: 27.94-118.62) in the case of death. The presence of any comorbidity more than doubled the odds ratio, with hypertension-diabetes as the riskiest combination. While the wave peaks increased over time, the odds ratios for developing severe disease (waves 2, 3, and 4 to wave 1) decreased to 0.15 (95% CI: 0.12-0.18) in the fourth wave., Conclusion: The health policy promoted by the Mexican government decreased hospitalizations and deaths, particularly among older adults with the highest risk of admission and death. Comorbidities augment the risk of developing severe illness, which is shown to rise by double in the Mexican population, particularly for those reported with hypertension-diabetes. Factors such as the decrease in the severity of the SARS-CoV2 variants, changes in symptomatology, and advances in the management of patients, vaccination, and treatments influenced the decrease in mortality and hospitalizations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Loza, Wong-Chew, Jiménez-Corona, Zárate, López, Ciria, Palomares, García-López, Iša, Taboada, Rosales, Boukadida, Herrera-Estrella, Mojica, Rivera-Gutierrez, Muñoz-Medina, Salas-Lais, Sanchez-Flores, Vazquez-Perez, Arias and Gutiérrez-Ríos.)

The prevalence of undernutrition in Mexican children younger than 5 years old has been 14% since 2006. There are clinical practice guidelines for mild to moderate malnutrition in children in the Mexican health system; however, they are not applied. In addition, the knowledge and practices of health professionals (HP) to treat malnutrition in health centers are insufficient to perform adequate assessments and correct treatments. An impact evaluation of an interdisciplinary educational intervention was carried out on 78 HPs for the treatment of children with mild to moderate malnutrition of low resources, with 39 in the intervention group and 37 in the counterfactual group, estimated as the comparison group. A Food and Agriculture Organization (FAO)-validated questionnaire adapted to child malnutrition about knowledge, attitudes, and practices was applied before, after, and 2 months after a malnutrition workshop. The difference-in-differences analysis showed that the educational intervention group had a significant improvement in knowledge, attitudes, and practices before and after the intervention (grades of 54.6 to 79.2 respectively, p = 0.0001), compared with the comparison group (grades of 79.2 and 53.4, respectively, p = 0.0001), which was maintained over two months (grades of 71.8 versus 49.8, p = 0.0001, respectively). The multivariate analysis showed that the probability of improvement in learning by 30% was 95-fold higher in the educational intervention group versus the comparison group, OR = 95.1 (95% CI 14.9-603.0), and this factor was independent of sex, age, education, or hospital position. Despite the availability of clinical practice guidelines for the assessment and treatment for child malnutrition, education in malnutrition for HPs is effective and needed to achieve a significant improvement in children's health.

Introduction: SARS-CoV-2 continues to have a high rate of contagion worldwide. The new variant of concern, Omicron, has mutations that decrease the effectiveness of vaccines and evade antibodies from previous infections resulting in a fourth wave of the pandemic. It was identified in Mexico in December 2021., Methods: The Traveler's Preventive Care Clinic from the Faculty of Medicine UNAM at Mexico City International Airport has performed rapid antigen and PCR SARS CoV2 tests since January 2021 to comply with the new travel requirements. Demographic and clinical characteristics were collected from each passenger and the fourth wave of the pandemic in Mexico mainly caused by Omicron was analyzed in the travelers., Results: A total of 5176 travelers attended the clinic between the second half of December 2021 and January 2022. Ten percent of all the tests performed were positive (13% of PCR and 9.3% of antigens, p = 0.001). Most of the SARS CoV2 positive cases were asymptomatic (78%), with a ratio of 3.5:1 over the symptomatic. By age groups, this ratio was higher for those under 20 years old (8.7:1)., Discussion: This study shows the rapid escalation of positivity that occurred in Mexico, detected in travelers, from the second half of December 2020 and throughout the month of January 2021. The incidence of COVID-19 was extremely high in travelers who were mostly asymptomatic for the period under study., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: In the paediatric population, coronavirus disease (COVID-19) is usually asymptomatic or mild, but there are also severe and fatal cases., Methods: We analysed data on COVID-19 cases from the national and state-level databases of the Federal Ministry of Health of Mexico and the Department of Health of Mexico City to determine the clinical characteristics and risk factors for mortality in children. We used Cox proportional hazards regression analysis to calculate the risk of death., Results: The national and Mexico City databases had recorded a total of 18,465 (2.8%) and 5,733 (4.2%) confirmed cases of COVID-19, respectively, in individuals aged less than 18 years as of September 2020. The median age at diagnosis was 12 years (range: 0-17). The differences between cases in the national vs Mexico City databases were: 12.5% vs 8.2% of patients were hospitalised; 6% vs 3.5% had pneumonia; 2.4% vs 1.9% were admitted to the intensive care unit (ICU), and 1.3% vs 0.7% died. The independent risk factors significantly associated with a higher probability of death were pneumonia, hypertension, obesity, immunosuppression and intubation., Conclusion: In Mexico, 2.8% of all confirmed cases of COVID-19 occurred in individuals under 18 years, with a median age of 12 years and a mortality of 1.3%. The identified predictors of mortality were pneumonia, admission to the ICU, obesity, hypertension, immunosuppression, diabetes, chronic lung disease and renal disease., (© 2021 Asociación Española de Pediatría. Published by Elsevier España, S.L.U.)

Introduction: The gut microbiota affects the development of the gut immune system in early life. Perturbations to microbiota structure and composition during this period can have long-term consequences on the health of the individual, through its effects on the immune system. Research in the last few decades has shown that probiotic administration can reverse these effects in strain- and environment-specific ways. Bacillus clausii ( B. clausii ) has been in use for many decades as a safe and efficacious probiotic, but its mode of action has not yet been completely elucidated., Areas Covered: In this review, we discuss how the gut immune system works, the factors that affect its functioning, and the plethora of research highlighting its role in various diseases. We also discuss the known modes of action of Bacillus probiotics, and highlight the preclinical and clinical evidence that reveal how B. clausii acts to bolster gut defense., Expert Opinion: We anticipate that the treatment and/or prevention of dysbiosis will be central to managing human health and disease in the future. Discovering the pathophysiology of autoimmune diseases, infections, allergies, and some cancers will aid our understanding of the key role played by microbial communities in these diseases.

In this study, we analyzed the sequences of SARS-CoV-2 isolates of the Delta variant in Mexico, which has completely replaced other previously circulating variants in the country due to its transmission advantage. Among all the Delta sublineages that were detected, 81.5 % were classified as AY.20, AY.26, and AY.100. According to publicly available data, these only reached a world prevalence of less than 1%, suggesting a possible Mexican origin. The signature mutations of these sublineages are described herein, and phylogenetic analyses and haplotype networks are used to track their spread across the country. Other frequently detected sublineages include AY.3, AY.62, AY.103, and AY.113. Over time, the main sublineages showed different geographical distributions, with AY.20 predominant in Central Mexico, AY.26 in the North, and AY.100 in the Northwest and South/Southeast. This work describes the circulation, from May to November 2021, of the primary sublineages of the Delta variant associated with the third wave of the COVID-19 pandemic in Mexico and highlights the importance of SARS-CoV-2 genomic surveillance for the timely identification of emerging variants that may impact public health.

During the coronavirus disease 2019 (COVID-19) pandemic, the emergence and rapid increase of the B.1.1.7 (Alpha) lineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first identified in the United Kingdom in September 2020, was well documented in different areas of the world and became a global public health concern because of its increased transmissibility. The B.1.1.7 lineage was first detected in Mexico during December 2020, showing a slow progressive increase in its circulation frequency, which reached its maximum in May 2021 but never became predominant. In this work, we analyzed the patterns of diversity and distribution of this lineage in Mexico using phylogenetic and haplotype network analyses. Despite the reported increase in transmissibility of the B.1.1.7 lineage, in most Mexican states, it did not displace cocirculating lineages, such as B.1.1.519, which dominated the country from February to May 2021. Our results show that the states with the highest prevalence of B.1.1.7 were those at the Mexico-U.S. border. An apparent pattern of dispersion of this lineage from the northern states of Mexico toward the center or the southeast was observed in the largest transmission chains, indicating possible independent introduction events from the United States. However, other entry points cannot be excluded, as shown by multiple introduction events. Local transmission led to a few successful haplotypes with a localized distribution and specific mutations indicating sustained community transmission. IMPORTANCE The emergence and rapid increase of the B.1.1.7 (Alpha) lineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) throughout the world were due to its increased transmissibility. However, it did not displace cocirculating lineages in most of Mexico, particularly B.1.1.519, which dominated the country from February to May 2021. In this work, we analyzed the distribution of B.1.1.7 in Mexico using phylogenetic and haplotype network analyses. Our results show that the states with the highest prevalence of B.1.1.7 (around 30%) were those at the Mexico-U.S. border, which also exhibited the highest lineage diversity, indicating possible introduction events from the United States. Also, several haplotypes were identified with a localized distribution and specific mutations, indicating that sustained community transmission occurred in the country.

Background: By end December of 2021, COVID-19 has infected around 276 million individuals and caused over 5 million deaths worldwide. Infection results in dysregulated systemic inflammation, multi-organ dysfunction, and critical illness. Cells of the central nervous system are also affected, triggering an uncontrolled neuroinflammatory response. Low doses of glucocorticoids, administered orally or intravenously, reduce mortality among moderate and severe COVID-19 patients. However, low doses administered by these routes do not reach therapeutic levels in the CNS. In contrast, intranasally administered dexamethasone can result in therapeutic doses in the CNS even at low doses., Methods: This is an approved open-label, multicenter, randomized controlled trial to compare the effectiveness of intranasal versus intravenous dexamethasone administered in low doses to moderate and severe COVID-19 adult patients. The protocol is conducted in five health institutions in Mexico City. A total of 120 patients will be randomized into two groups (intravenous vs. intranasal) at a 1:1 ratio. Both groups will be treated with the corresponding dexamethasone scheme for 10 days. The primary outcome of the study will be clinical improvement, defined as a statistically significant reduction in the NEWS-2 score of patients with intranasal versus intravenous dexamethasone administration. The secondary outcome will be the reduction in mortality during hospitalization., Conclusions: This protocol is currently in progress to improve the efficacy of the standard therapeutic dexamethasone regimen for moderate and severe COVID-19 patients., Trial Registration: ClinicalTrials.gov NCT04513184 . Registered November 12, 2020. Approved by La Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS) with identification number DI/20/407/04/36. People are currently being recruited., (© 2022. The Author(s).)

Introduction: Several reports have emerged describing the long-term consequences of COVID-19 and its effects on multiple systems., Methods: As further research is needed, we conducted a longitudinal observational study to report the prevalence and associated risk factors of the long-term health consequences of COVID-19 by symptom clusters in patients discharged from the Temporary COVID-19 Hospital (TCH) in Mexico City. Self-reported clinical symptom data were collected via telephone calls over 90 days post-discharge. Among 4670 patients, we identified 45 symptoms across eight symptom clusters (neurological; mood disorders; systemic; respiratory; musculoskeletal; ear, nose, and throat; dermatological; and gastrointestinal)., Results: We observed that the neurological, dermatological, and mood disorder symptom clusters persisted in >30% of patients at 90 days post-discharge. Although most symptoms decreased in frequency between day 30 and 90, alopecia and the dermatological symptom cluster significantly increased ( p  < 0.00001). Women were more prone than men to develop long-term symptoms, and invasive mechanical ventilation also increased the frequency of symptoms at 30 days post-discharge., Conclusion: Overall, we observed that symptoms often persisted regardless of disease severity. We hope these findings will help promote public health strategies that ensure equity in the access to solutions focused on the long-term consequences of COVID-19., Competing Interests: Conflict of interest statement: The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The Carlos Slim Foundation funded this study. The funding source was involved in the design of the study, analysis, interpretation of data, and in writing the manuscript. R.R.V.V., E.X.R.C., C.A.R.V., M.L.R.C., S.A.F., M.S.F., H.H.B., L.M.C., M.A.A., J.A.H.C., N.A.M., L.F.C., L.R.G.C., and A.J.F. are employees of the Temporary COVID-19 Hospital. J.L.G., L.M.J., L.A.M.J., D-A.A-H., H.G-R., and R.T-C. are employees of The Carlos Slim Foundation. All authors confirm that they had full access to all the study data and accept responsibility to submit for publication., (© The Author(s), 2022.)

Annual influenza vaccination is recommended as a preventive measure for all patients with asthma since asthma exacerbations in children and adults are associated to viral infections including influenza. There is concern about the adequate immune response in asthmatics with ICS treatment. The production of antibodies to influenza in asthmatics has been demonstrated. However, cellular immunity is poorly understood. The aim of the study was to compare the humoral and cellular immune responses to influenza vaccine in asthmatic and healthy subjects. Twenty-five asthmatic patients attending the Allergy and Clinical Immunology Service at the Hospital General de Mexico and 25 healthy adults were included. Blood samples were obtained before, 4 and 12 months after immunization with influenza vaccine, influenza-specific antibodies were determined by the hemagglutination inhibition test and influenza-specific memory B, TCD4+, and TCD8 + lymphocytes were determined by flow cytometry. All the asthmatic patients received ICS treatment. The Geometric Mean titers for all influenza serotypes were similar in both groups; seropositivity and the cellular immune response increased in both groups over time and was comparable. Influenza vaccination in asthmatic patients with immunotherapy and ICS achieved protective antibody levels and cellular immunity over time comparable to healthy subjects.

Introduction: Patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may develop coronavirus disease 2019 (COVID-19). Risk factors associated with death vary among countries with different ethnic backgrounds. We aimed to describe the factors associated with death in Mexicans with confirmed COVID-19., Material and Methods: We analysed the Mexican Ministry of Health's official database on people tested for SARS-CoV-2 infection by real-time reverse transcriptase-polymerase chain reaction (rtRT-PCR) of nasopharyngeal fluids. Bivariate analyses were performed to select characteristics potentially associated with death, to integrate a Cox-proportional hazards model., Results: As of May 18, 2020, a total of 177,133 persons (90,586 men and 86,551 women) in Mexico received rtRT-PCR testing for SARS-CoV-2. There were 5332 deaths among the 51,633 rtRT-PCR-confirmed cases (10.33%, 95% CI: 10.07-10.59%). The median time (interquartile range, IQR) from symptoms onset to death was 9 days (5-13 days), and from hospital admission to death 4 days (2-8 days). The analysis by age groups revealed that the significant risk of death started gradually at the age of 40 years. Independent death risk factors were obesity, hypertension, male sex, indigenous ethnicity, diabetes, chronic kidney disease, immunosuppression, chronic obstructive pulmonary disease, age > 40 years, and the need for invasive mechanical ventilation (IMV). Only 1959 (3.8%) cases received IMV, of whom 1893 were admitted to the intensive care unit (96.6% of those who received IMV)., Conclusions: In Mexico, highly prevalent chronic diseases are risk factors for death among persons with COVID-19. Indigenous ethnicity is a poorly studied factor that needs more investigation., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2020 Termedia & Banach.)

Human rhinovirus (HRV) affects the lower and upper respiratory tract, however, some studies suggest that HRV infection can lead to extrapulmonary complications in critical illness. Moreover, some reports have shown the presence of HRV in patients with Central Nervous System (CNS) disease. During a CNS infection, the microglia cells are the first line of defense against pathogens. In this study, the susceptibility of the human microglial clone 3 cell line (HMC3) to HRV infection was analyzed. Our findings demonstrate for the first time that HRV is capable of completing the entire viral cycle in microglial cells., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Pneumonia caused 704,000 deaths in children younger than 5 years in 2015. Zinc is an important micronutrient due to its role in immune function. Since 2004, WHO recommends zinc supplementation for children with diarrhea to shorten the duration and decrease severity. Zinc supplementation for children with pneumonia is controversial. Methods: A randomized controlled clinical trial was conducted, and 103 children 1 month to 5 years old with pneumonia were included. Zinc or placebo was given during hospitalization. Clinical symptoms were recorded, and a blood draw was obtained to determine serum zinc levels, lymphoproliferation, and cytokines at hospitalization and at discharge of the patient; a nasal wash was obtained to detect viral or bacterial pathogens by multiplex RT-PCR. Results: Zinc supplementation improved in fewer hours the clinical status (76 ± 7 vs. 105 ± 8, p = 0.01), the respiratory rate (37 ± 6 vs. 57 ± 7, p = 0.04), and the oxygen saturation (53 ± 7 vs. 87 ± 9, p = 0.007) compared to the placebo group. An increase in IFNγ and IL-2 after treatment in the zinc group was observed. Conclusions: Zinc supplementation improved some clinical symptoms in children with pneumonia in fewer hours and induced a cellular immune response. Clinical Trial Registration: The trial was retrospectively registered in ClinicalTrials.gov, identifier NCT03690583, URL https://clinicaltrials.gov/ct2/show/NCT03690583?term=zinc+children&cond=Pneumonia&draw=2&rank=1., (Copyright © 2019 Acevedo-Murillo, García León, Firo-Reyes, Santiago-Cordova, Gonzalez-Rodriguez and Wong-Chew.)

Malnutrition in children younger than 5 years old has persisted in time (13.5% in 1988 to 12.3% in 2012) in Mexico City. A quasi-experimental study was performed. An educational intervention was given twice a month for 6 months to mothers of mild to moderate malnourished children 1 to 5 years old. Weight, height, and body mass index of the children were obtained at the beginning and 3 and 6 months after the intervention. Thirteen mothers and 15 children were included. The baseline mean weight/age in Z score was -1.49 ± 0.65, which improved to -1.19 ± 0.60 ( P = 0.001; per protocol analysis). Linear regression analysis showed a P of 0.006 of the mothers' adherence to improve children's weight. The educational intervention decreased the weight deficit after 6 months with the same economic resources of the family; hence, the adherence of the mothers to the educational intervention is relevant to improve the nutritional status of their children., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Sonia Sanchez-Encalada and Myrna M. Talavera-Torres declare that they do not have a commercial or other association that might pose a conflict of interest. Rosa M. Wong-Chew has received personal fees from Sanofi as speaker and GSK and Abbvie as consultant outside the submitted work., (© The Author(s) 2019.)

Introduction: Necrotizing fasciitis (NF) is a severe infectious condition associated with significant morbidity and mortality and characteristically has a higher incidence in adults; pediatric cases are very rare. In this case report we describe, the clinical presentation, management and outcome of a patient with necrotizing fasciitis of the neck and head complicated with chronic osteomyelitis., Presentation of the Case: An 18 month-old, latin, male, diagnosed with rickets and Crouzon syndrome, twenty-four hours post- craniofacial remodeling surgery presented tissue edema, indurated skin and violaceous and well delimited lesions in the neck and head. The patient developed septic shock, acute osteomyelitis and infection of the cranial grafts. Multiple surgical lavages, debridation of the necrotic tissue and resection of the affected bone, in combination with multiple antibiotics, laboratory test methods, VAC therapy and hyperbaric oxygen were required for successful treatment and full recovery of the patient., Discussion: Although early antibiotic therapy and critical care are basic for the treatment of patients with NF, early aggressive surgical treatment is crucial for an adequate outcome. Adjuvant treatment for NF such as the Vacuum-assisted closure and the hyperbaric oxygen therapy are very useful to accelerate wound healing. Moreover, special laboratory test methods such as the checkerboard can be used to determine the adequate antimicrobial combination of drugs in the case of multi resistant organisms., Conclusions: Early diagnosis, adequate antibiotic therapy and aggressive surgical debridement of the necrotic tissue combined with VAC and hyperbaric oxygen therapy played an important role in the successful treatment of NF., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Acute respiratory infections are the leading cause of mortality in children worldwide, especially in developing countries. Pneumonia accounts for 16% of all deaths of children under 5 years of age and was the cause of death of 935000 children in 2015. Despite its frequency and severity, information regarding its etiology is limited. The aim of this study was to identify respiratory viruses associated with community-acquired pneumonia (CAP) in children younger than 5 years old., Methods: One thousand four hundred and four children younger than 5 years of age with a clinical and/or radiological diagnosis of CAP in 11 hospitals in Mexico were included. Nasal washes were collected, placed in viral medium, and frozen at -70°C until processing. The first 832 samples were processed using the multiplex Bio-Plex/Luminex system and the remaining 572 samples using the Anyplex multiplex RT-PCR. Clinical data regarding diagnosis, clinical signs and symptoms, radiographic pattern, and risk factors were obtained and recorded., Results: Of the samples tested, 81.6% were positive for viruses. Respiratory syncytial virus (types A and B) was found in 23.7%, human enterovirus/rhinovirus in 16.6%, metapneumovirus in 5.7%, parainfluenza virus (types 1-4) in 5.5%, influenza virus (types A and B) in 3.6%, adenovirus in 2.2%, coronavirus (NL63, OC43, 229E, and HKU1) in 2.2%, and bocavirus in 0.4%. Co-infection with two or more viruses was present in 22.1%; 18.4% of the samples were negative. Using biomass for cooking, daycare attendance, absence of breastfeeding, and co-infections were found to be statistically significant risk factors for the presence of severe pneumonia., Conclusions: Respiratory syncytial virus (types A and B), human enterovirus/rhinovirus, and metapneumovirus were the respiratory viruses identified most frequently in children younger than 5 years old with CAP. Co-infection was present in an important proportion of the children., (Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

We report the complete genome sequence of the first Mexican human coronavirus (HCoV) OC43, obtained by new-generation sequencing and a metagenomic approach, isolated from a child hospitalized with pneumonia. The genome is closely related to the other OC43 genome sequences available, ranging from 99.8% to 98.2% nucleotide sequence identity., (Copyright © 2016 Taboada et al.)

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.

Background: Most of the studies characterizing the incidence of rhinovirus (RV) have been carried out in hospitalized children and in developed countries. In those studies, RV-C has been associated with more severe respiratory tract infections than RV species A and B. In this study we determined the frequency and diversity of RV strains associated with upper and lower respiratory tract infections (URTI, LRTI) in Mexico, and describe the clinical characteristics of the illness associated with different RV species., Methods: A prospective surveillance of 526 and 250 children with URTI and LRTI was carried out. Respiratory samples were analyzed by RT-PCR for viruses. The 5' untranslated region of the RV genome was amplified and sequenced., Results: In the case of URTI, 17.5% were positive for RV, while this virus was found in 24.8% of LRTI. The RV species was determined in 73 children with URTI: 61.6% were RV-A, 37% RV-C and, 1.4% RV-B; and in 43 children with LRTI: 51.2% were RV-A, 41.8% RV-C, and 7% RV-B. No significant differences in clinical characteristics were found in patients with RV-A or RV-C infections. A high genetic diversity of RV strains was found in both URTI and LRTI., Conclusions: Both RV-A and RV-C species were frequently found in hospitalized as well as in outpatient children. This study underlines the high prevalence and genetic diversity of RV strains in Mexico and the potential severity of disease associated with RV-A and RV-C infections.

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.

Viruses are the most frequent cause of respiratory disease in children. However, despite the advanced diagnostic methods currently in use, in 20 to 50% of respiratory samples a specific pathogen cannot be detected. In this work, we used a metagenomic approach and deep sequencing to examine respiratory samples from children with lower and upper respiratory tract infections that had been previously found negative for 6 bacteria and 15 respiratory viruses by PCR. Nasal washings from 25 children (out of 250) hospitalized with a diagnosis of pneumonia and nasopharyngeal swabs from 46 outpatient children (out of 526) were studied. DNA reads for at least one virus commonly associated to respiratory infections was found in 20 of 25 hospitalized patients, while reads for pathogenic respiratory bacteria were detected in the remaining 5 children. For outpatients, all the samples were pooled into 25 DNA libraries for sequencing. In this case, in 22 of the 25 sequenced libraries at least one respiratory virus was identified, while in all other, but one, pathogenic bacteria were detected. In both patient groups reads for respiratory syncytial virus, coronavirus-OC43, and rhinovirus were identified. In addition, viruses less frequently associated to respiratory infections were also found. Saffold virus was detected in outpatient but not in hospitalized children. Anellovirus, rotavirus, and astrovirus, as well as several animal and plant viruses were detected in both groups. No novel viruses were identified. Adding up the deep sequencing results to the PCR data, 79.2% of 250 hospitalized and 76.6% of 526 ambulatory patients were positive for viruses, and all other children, but one, had pathogenic respiratory bacteria identified. These results suggest that at least in the type of populations studied and with the sampling methods used the odds of finding novel, clinically relevant viruses, in pediatric respiratory infections are low.

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.

The immune response to influenza vaccination in children with cancer is controversial. The objective of this study was to characterize the cellular and humoral immune responses to an influenza vaccine in children with cancer who were receiving chemotherapy. In this study, children with cancer, who were not previously immunized, received an influenza vaccine via intramuscular injection. Blood samples were obtained prior to and at 4 weeks after immunization. Antibodies were measured using a hemagglutination inhibition (HI) assay. Cell-mediated immunity was measured by specific lymphoproliferation with (3)H-thymidine incorporation and by measuring cell frequencies following staining with monoclonal antibodies (CD8, CD4, CD19, CD45RA and CD27) using flow cytometry following incubation with the influenza antigen for 5 days. Geometric mean titers (GMT), mean counts per minute (cpm), cell frequencies prior to and following vaccination and percentage patient responses were compared using the Mann-Whitney non-parametric U and Chi-square tests; where p<0.05 was considered to indicate a statistically significant result. A total of 56 children were included. Their mean age was 6.64±3.61 years. Acute lymphoblastic leukemia (ALL) was diagnosed in 75, solid tumors in 23 and lymphoma in 2% of the children. Subjects with titers ≥40 hemagglutination units (HU) increased from 43% prior to vaccination to 73% following vaccination (p=0.01), whereas the GMT increased from 31.35 [95% confidence interval (CI), 29-111] to 143.45 HU (95% CI, 284-640) following vaccination (p<0.001). An increase in CD45RA expression in CD8(+) T cells was observed following vaccination (p=0.01). An increase in CD27 expression was observed in the CD4/8-negative cell population stimulated with the influenza antigen following vaccination (p<0.05). No serious adverse effects were observed. An increase in the seropositivity rate and GMT values following influenza vaccination were also observed. Influenza immunization was well tolerated among these children with cancer and increased the humoral and cellular immune responses with the activation of probable lymphoid precursors.

Objective: To describe the frequency of respiratory viruses and clinical characteristics in children with respiratory signs and symptoms in a tertiary care center in Mexico., Material and Methods: Patients with a clinical diagnosis of respiratory infection and a positive immunofluorescence result (Light Diagnostics) from January 2004 to October 2006 were included., Results: From the 986 nashopharyngeal samples, 138 (14%) were positive by immunofluorescence. The frequency was: 80% RSV, 8% parainfluenza 1, 5% parainfluenza 3, 2% adenovirus, 2% influenza A, 1% parainfluenza 2 and 1% influenza B., Conclusions: Respiratory viruses were detected in 14% of samples tested. RSV was the most frequently identified virus and was associated with pneumonia and bronchiolitis in children younger than 3 years old.

Objective: The objective of the study was to evaluate the immune response to measles vaccine of HIV-infected adults in comparison to HIV non-infected adults., Design: We conducted a cross-sectional study to identify adults lacking measles antibodies. 26 HIV-infected patients and 22 controls found to be measles seronegative in the cross-sectional study, received the MMR vaccine. We prospectively followed patients and measured measles antibodies, and cellular proliferative responses against measles antigens. We registered all adverse events at baseline, 3 and 12 months after vaccination., Methods: We determined measles antibodies by ELISA and cellular proliferative response in PBMC's at baseline, and repeated measurements at 3 and 12 months after vaccination., Results: The humoral immune response to the vaccine between HIV-infected adults and the HIV-uninfected group was not statistically different at 3 months (81% vs. 86% respectively). One year after vaccination, a higher proportion of HIV-infected adults had lost measles antibodies in contrast to controls. The cellular response was not statistically different between the groups at baseline, 3 and 12 months after immunization despite the waning of antibodies at 12 months. No severe adverse events were observed. Most patients were receiving HAART and had a mean CD4+ cell count of 496 cells/mL., Conclusions: The initial humoral immune response to measles vaccine was not different between HIV-infected adults and HIV-uninfected adults. However, HIV-infected adults have a rapid decline of measles antibodies despite their high CD4+ cell count and sustained cellular proliferative response.

Booster doses of MMR vaccine equal in dosage to injected doses were aerosolized into a 3/4 l bag that inflated in 4s. The bag was then attached to valved masks, and its contents rapidly inhaled in one or two deep breaths by preschool Mexican children. Antibody responses in the children exposed to the aerosolized measles component were superior to those noted after injection, while responses to the mumps and rubella components were equivalent. The new method appears to be effective, safe, and has several advantages over previously used methods. Further explorations of the approach seem merited.

Unlabelled: Aerosol measles vaccination has been found to be more immunogenic than subcutaneous administration as a booster in school aged children, and immunogenic in 12-month-old children as a primary dose. The objective of the study was to evaluate immunogenicity to aerosol measles vaccine in 9-month-old children., Methods: Nine-months-old infants received Edmonston-Zagreb measles vaccine by aerosol (10(3.58) CCID50/0.1 mL, estimated retained dose 10(2.81) CCID50 or subcutaneous route (10(4.28) CCID50/0.5 mL); cellular and humoral immunity and adverse events were assessed., Results: Measles-specific T cell proliferative responses developed in 42% of children given aerosolized vaccine compared with 67% of those who received subcutaneous vaccine (p = 0.01); the mean stimulation index (SI) was 4.4+/-0.7 versus 6.9+/-1, respectively, (p = 0.05). Seroconversion rates were 33 and 92% after aerosol or subcutaneous immunization (p < 0.001). Among infants who developed serologic responses, measles geometric mean titers (GMT; 95% CI) by neutralizing antibody assay were 215 mIU/mL (115-400) in aerosol vaccine recipients and 411 mIU/mL (345-490) in those given subcutaneous vaccine (p = 0.06)., Conclusions: The proportion of 9-month-old infants who developed cellular and/or humoral immunity to measles was lower in the aerosol group but measles antibody and T cell responses were comparable among those who developed measles immunity. Differences in response rates are attributable to the lower aerosol dose. Improving aerosol delivery or increasing the dose may enhance immunogenicity of primary aerosol measles vaccination in this age group.

Infants were immunized by aerosol (10(3.6) plaque-forming units [pfu]/dose) or subcutaneous (sc) (10(4.27) pfu/dose) administration of Edmonston-Zagreb measles vaccine. Measles-specific T cell proliferative responses with a stimulation index of > or =3 developed in 72% of children given aerosol-administered vaccine, compared with 87% given s.c.-administered vaccine (P =.06). Seroconversion rates were 90% after aerosol-administered vaccine and 100% after s.c.-administered vaccine (P=.01), and measles geometric mean titers were 237 milli-international units (mIU) (95% confidence interval [CI], 146-385 mIU) and 487 mIU (95% CI, 390-609 mIU) in each group, respectively (P=.01). Measles-specific T and B cell responses were weaker after aerosol than after sc vaccination, indicating a need to use a higher aerosol dose to achieve optimal immunogenicity.

The objective of this study was to characterize the kinetics of the cellular and humoral immune responses elicited by measles vaccine given to previously immune adults. The cellular and humoral immune responses to measles were measured in seven healthy adults, before vaccination and at 1, 2, 3, and 4 weeks and 3 months after vaccination, using measles-specific T-cell proliferation and plaque reduction neutralization assays. All study subjects had detectable measles antibodies, but only six (85%) showed protective titers, defined as >1:120, before immunization. However measles-specific T-cell proliferation was not detectable before vaccination in any of the subjects. The six subjects with protective titers showed a positive stimulation index (SI) of >3.0 within the first 4 weeks after vaccination, an SI of 5 at the 4th week, and an SI of 3 at 3 months after vaccination. The subject with a low antibody titer (1:99) before vaccination developed a high SI at 3 months after vaccination. This subject was the only participant whose neutralizing antibody titers increased more than 4-fold by 3 months after vaccination. No significant increases in geometric mean titers were detected in the other six subjects during the follow-up period. These data suggest that high measles antibody titers interfere with the humoral response in subjects who receive a booster immunization, whereas the cellular response is boosted at least transiently, after revaccination., (Copyright 2003 Wiley-Liss, Inc.)