Design of an observational multi-country cohort study to assess immunogenicity of multiple vaccine platforms (InVITE)

In response to the COVID-19 pandemic, COVID-19 vaccines have been developed, and the World Health Oraganization (WHO) has granted emergency use listing to multiple vaccines. Studies of vaccine immunogenicity data from implementing COVID-19 vaccines by national immunization programs in single studies spanning multiple countries and continents are limited but critically needed to answer public health questions on vaccines, such as comparing immune responses to different vaccines and among different populations.

Low Incidence and Mortality by SARS-CoV-2 Infection Among Healthcare Workers in a Health National Center in Mexico: Successful Establishment of an Occupational Medicine Program

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Healthcare workers (HCWs) constitute a population which is significantly affected by SARS-CoV-2 infection worldwide. In Mexico, the Instituto Nacional de Enfermedades Respiratorias (INER) is the principal national reference of respiratory diseases.

Aim: To evaluate the efficiency of the INER-POL-TRAB-COVID19 program to mitigate the SARS-CoV-2 infection risk among the INER-healthcare workers (INER-HCW).

Methods: Currently, the INER has 250 beds and 200 respiratory ventilators to support COVID-19 patients in critical condition. On March 1st, 2020, the INER-POL-TRAB-COVID19 program was launched to mitigate the SARS-CoV-2 infection risk among the INER-HCW.

Findings: From March 1st to October 1st, 2020, 71.5% of INER-HCWs were tested for SARS-CoV-2 infection, and 77% of them were frontline workers. Among the tested INER-HCWs, 10.4% were positive for SARS-CoV-2 infection. Nonetheless, nosocomial infection represented only 3.8% of the cases and the mortality was null. Fifty-three of INER-HCWs positive to SARS-CoV-2 had a negative test 42–56 days post-diagnosis and were returned to service. Finally, although a change in the PPE implemented on May 11th, 2020, the incidence of SARS-CoV-2 infection was not affected.

Conclusion: INER has a lower incidence of HCWs infected with SARS-CoV-2 as compared to the mean of the national report. The implementation of the INER-POL-TRAB-COVID19 program is efficient to decrease the risk of infection among the HCWs. Our findings suggest that the implementation of a similar program at a national level can be helpful to provide a safe environment to HCWs and to prevent the collapse of health institutions.

Tobacco control in Mexico: a decade of progress and challenges

Mexico was the first country in the Americas to sign and ratify the World Health Organization's (WHO) Framework Convention on Tobacco Control (FCTC) in 2004. More than a decade later, it is appropriate to evaluate legislative and regulatory progress and the associated challenges; and also, to propose a roadmap to prioritize the problems to be addressed to achieve long-term sustainable solutions. Mexico has made substantial progress in tobacco control. However, regulations have been only weakly enforced. The tobacco industry continues to interfere with full implementation of the WHO-FCTC. As a result, tobacco consumption remains stable at about 17.6%, with a trend upwards among vulnerable groups: adolescents, women and low-income groups. The growing popularity of new tobacco products (electronic cigarettes or e-cigs) among young Mexicans is an increasing challenge. Our review reveals the need to implement all provisions of the WHO-FCTC in its full extent, and that laws and regulations will not be effective in decreasing the tobacco epidemic unless they are strictly enforced.

EV-D68 infection in children with asthma exacerbation and pneumonia in Mexico City during 2014 autumn

BACKGROUND

Human enterovirus D68 (EV-D68) recently caused an increase in mild-to-severe pediatric respiratory cases in North America and some European countries. Even though few of these children presented with acute paralytic disease, direct causal relationship cannot yet be assumed.

OBJECTIVES

The purposes of this report were to describe the clinical findings of an outbreak of EV-D68 infection in Mexico City and identify the genetic relationship with previously reported strains.

PATIENTS/METHODS

Between September and December 2014, 126 nasopharyngeal samples (NPS) of hospitalized children <15 years of age with ARI were tested for the presence of respiratory viruses using a multiplex RT-qPCR and EV-D68-specific RT-qPCR. Clinical, epidemiological, and demographic data were collected and associated with symptomatology and viral infections. Phylogenetic analyses were performed using VP1 region.

RESULTS

Enterovirus/rhinovirus infection was detected in 40 patients (31·7%), of which 24 patients were EV-D68-positive. EV-D68 infection prevailed over September and October 2014 and was associated with neutrophilia and lymphopenia, and patients were more likely to develop hypoxemia. Phylogenetic analyses showed that Mexican EV-D68 belongs to the new B1 clade.

CONCLUSIONS

This is the first EV-D68 outbreak described in Mexico and occurred few weeks after the United States reported similar infections. Although EV-D68 belongs to new B1 clade, no neurological affection was observed.

Genetic Risk Determinants for Cigarette Smoking Dependence in Mexican Mestizo Families

INTRODUCTION

Tobacco smoking is a leading cause of mortality in developed and developing countries. Despite antitobacco and smoke-free policies, the prevalence of active smokers in Mexican urban populations has remained stable. Mexican smokers differ from Caucasian and other ethnic groups, probably due to sociocultural and genetic background characteristics. This study explored the effect of known genetic variants on smoking behavior in Mexico City residents.

METHODS

Three hundred sixty-four Mexican Mestizo Mexico City residents from 87 families with at least one smoker were assessed for association of 12 gene variants of six candidate genes (CHRNA4, CHRNB2, DRD2, ANKK1, SLC6A3, and CYP2A6) with cigarette consumption, age of initiation and smoking duration. The Family Based Association Test, an extension of the Transmission Disequilibrium Test, was used to perform family-based association analysis.

RESULTS

The Family Based Association Test showed statistically significant association between the rs2072658 polymorphism of the CHRNB2 gene and smoking-related phenotypes such as: smoking status (SS), age of onset (AO), years of smoking, and psychological dependence (PD) evaluated by the Glover-Nilsson Smoking Behavior Questionnaire. After Bonferroni correction, only the association with AO remained significant (P = .003). Statistically significant association was also observed for the CYP2A6 rs28399433 T allele with SS (P = .003) and PD (P = .003).

CONCLUSIONS

Our results indicate effects of the rs2072658 CHRNB2 and rs28399433 CYP2A6 gene variants on AO, SS and PD in Mexican Mestizo smokers. A mild effect of other analyzed gene variants, which may contribute to a putative polygenic predisposition for smoking, is suggested.

IMPLICATIONS

The understanding of genetic and environmental determinants in the Mexican population is important for other Latin American populations as well, living in their own countries or moving to other ones, particular due to the current migration characteristics and particular genetic background like the Mexican Mestizo and other Central American populations with similar characteristics and migrating to neighbor developed countries, introducing their own smoking behavior and contributing importantly to the genetic pool of the receptor country.

[Effect of tobacco smoking, respiratory symptoms and asthma on spirometry among adults attending a check-up clinic in Mexico City]

OBJECTIVE

To evaluate the effect of tobacco smoking, respiratory symptoms, and asthma on lung function among Mexican adults who were evaluated during a medical exam in a private health clinic.

MATERIAL AND METHODS

Reference prediction equations were generated for spirometry parameters [forced vital capacity (FVC), forced expired volume in one second (FEV1) and FEV1/FVC] based on multiple linear regression models. The effect of tobacco smoking, respiratory symptoms and asthma on these equations were explored.

RESULTS

Spirometry tests were performed on 919 subjects from 14 to 86 years of age. Asthma decreased FVC and FEV1 in men with a R2 change <1%. Respiratory symptoms decreased the FEV1/FVC ratio in both sexes. Tobacco smoking was associated with a significant reduction in FEV in women.

CONCLUSIONS

Asthma lightly reduced lung function in males while tobacco smoking decreased FEV, particularly in females.

Frequency and Correlates of Adverse Events in a Respiratory Diseases Hospital in Mexico City

OBJECTIVES

To estimate the frequency of severe adverse events (AEs) during hospital stay as well as their type and correlates in a referral hospital for respiratory diseases, using methods similar to those used in the Harvard Medical Malpractice Study.

DESIGN

Retrospective review of medical records in a stratified sample of 836 patients drawn from a total of 4,555 hospital admissions registered during the year 2001.

SETTING

A referral tertiary-care hospital for patients with respiratory diseases located in Mexico City.

MAIN OUTCOME MEASURES

Weighted prevalence of AEs and odds ratios for correlates.

RESULTS

The overall weighted prevalence for AEs was 9.1% (95% confidence interval, 7.5 to 10.4%). Of these patients, 17% had a related transient disability, 52% had a prolonged hospital stay, and 26% had an AE that according to the reviewers contributed to their death. Of the total number of AEs, 74% were qualified as potentially preventable. Among all types of AEs, we identified as most relevant for a chest hospital the delayed surgical treatment of empyema, representing 11% of the total.

CONCLUSIONS

The frequency of AEs in a tertiary-care respiratory hospital is similar to that reported in general hospitals. A strategy to improve the treatment of empyema is needed.

[Characteristics of Mexican asthmatic subjects attending an outpatient service]

BACKGROUND

Despite the high prevalence of asthma in Mexico, studies describing general characteristics of these patients are scarce.

OBJECTIVE

To analyze the sociodemographic, clinical and respiratory functional profile of asthmatic patients attending for the first time the outpatient service of a tertiary-level hospital, as well as to investigate treatments already received and the abandonment rate.

METHODS

Adolescent and adult asthmatic subjects seen from February 2000 to November 2002 in the outpatient service of the National Institute of Respiratory Diseases, in Mexico City, were prospectively studied. Sociodemographic information was gathered and clinical and spirometric evaluations were carried out. The severity of the disease was classified according to international criteria.

RESULTS

A total of 1403 patients between 12 and 82 years of age, with predominance of the female gender, were included in the analysis. An 88.7% of patients had the mildest forms of the disease, 10% had moderate asthma, and 1.3% had severe asthma. While 21.4% had never received anti-asthma treatment, about one third of the remaining patients had received corticosteroids, independently of the asthma severity, indicating an over-treatment of the intermittent form of the disease and an under-treatment of persistent forms. A high abandonment rate (65.7%) was observed. A positive bronchodilator test was observed in 30.3% of patients with intermittent asthma, though this proportion increased to about 67% in those with moderate and severe asthma.

CONCLUSION

Mildest forms of the disease predominate among asthmatic patients attending for the first time an outpatient service, with a still very high frequency of inadequate use of corticosteroids.

Spirometric variability in a longitudinal study of school-age children

OBJECTIVES

To describe spirometric reproducibility in a longitudinal study of students from Mexico City, and also the frequency of subjects fulfilling quality criteria proposed for children.

SUBJECTS AND METHODS

Three thousand three hundred forty-seven participants from the third through sixth grades of elementary school were recruited to perform biannual spirometry, yielding a maximum of seven evaluations and a total of 15,563 tests. Standard recommendations of the American Thoracic Society (ATS) were followed, using dry rolling-seal volume spirometers.

RESULTS

During their first spirometric test, > 95% of the subjects fulfilled each of the quality criteria proposed by ATS for adults, though not all of them did so simultaneously. For example, only 72.4% obtained three acceptable maneuvers, reproducibility for FEV(1) and FVC to < 200 mL, and a small back-extrapolated volume that increased to 92.3% by the second test. Between phase 1 and phase 7 of the study, spirometry quality increased significantly, as a result of subject and technician training. Intratest and intertest (with a 6-month difference) spirometric variability was less in boys than in girls. Intratest variability was also lower in younger and taller subjects. Technicians contributed significantly to intratest and intertest variability, the latter decreasing if the same technician performed both evaluations.

CONCLUSION

Children > 7 years old can fulfill ATS criteria of quality after the first spirometric evaluation. To maintain quality of spirometric tests in longitudinal studies of children, a strict control is required, especially of technician performance.

Spirometric function in children of Mexico City compared to Mexican-American children

We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of age, using internationally accepted equipment and methodology, and to compare it to values reported for Mexican-American children. Out of a total of 6,803 students from primary school to high school studied cross-sectionally in the Mexico City metropolitan area, we selected 4,009 asymptomatic, nonobese, nonsmoker subjects to generate spirometric prediction equations. We describe regression equations for the main spirometric variables (log transformed) based on age, height, and weight, and separated for males and females. Spirometric function in the population studied was above that predicted for European (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142) or Mexican-American children, for the same age, height, and gender. On average, forced expiratory volume in 1 sec (FEV(1)) in Mexican children was 9.5% above that of Europeans (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142), 14% and 5% above Hispanics reported by (Coultas et al. [1988] Am Rev Respir Dis 138:1386-1392) and (Hsu et al. [1979] J Pediatr 95:14-23), respectively, and 5% above Mexican-Americans from the third National Health and Nutrition Examination Survey study. Similarly, FVC was 8%, 14%, 8%, and 5.6% above the figures predicted by the same authors. The largest errors of prediction of foreign equations occurred in extremely tall or short subjects, and therefore a single proportional adjustment is unfeasible.

[Reproducibility of spirometry in Mexican workers and international reference values]

OBJECTIVE

To describe spirometric function and adjustment to foreign prediction equations in Mexican workers claiming work related disability.

MATERIAL AND METHODS

We reviewed 5771 spirometries done at the Mexican National Institute of Respiratory Diseases performed with equipment and methods proposed by the American Thoracic Society. With the spirometries we generated multiple regression equations separated for men and women based on age and height, compared to other in common use reported by Knudson and Hankinson in North America and by Quanjer in europeans.

RESULTS

80% of the tests were reproducible for FVC and FEV1 according to ATS, whereas 10% were reproducible for neither. Mean FVC in men was 12% above values reported by Quanjer, 22% above Knudson, 3% above Hankinson and 6% above Rodriguez-Reynaga, whereas similar values for women were 18%, 10%, 0% and 1%. Excluding obese and those who had less than 2 acceptable maneuvers, the numbers increase by 1-2%. FEV1 was also above predicted.

CONCLUSIONS

Most workers requesting disability are able to generate a reproducible spirometry. However for the same gender, age and height, workers had a FEV1 and a FVC above normal values reported by Knudson and Quanjer and are more similar to those reported by Hankinson in Mexican-Americans. While a set of appropriate reference values are obtained, regression equations obtained from the studied group will generate less error in the evaluation of disability in mexican workers. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

[The domestic inhalation of the smoke from firewood and of other biological materials. A risk for the development of respiratory diseases]

A high proportion of the world population, especially in developing countries, is exposed to indoor pollutants produced by inefficient biomass stoves. The levels of pollutants, including toxins and carcinogens in the kitchen are usually very high. This potential pathogenic exposure has been scarcely studied. The exposure to biomass smoke has been associated to chronic bronchitis and chronic airflow obstruction in adults and to acute respiratory infections in children. At the National Institute of Pulmonary Diseases in Mexico, we have observed the entire spectrum of diseases associated with tobacco in people who never smoked and who were exposed to wood smoke. Women exposed to wood smoke had a five-fold risk of chronic bronchitis and chronic airflow obstruction, as compared to the non-exposed, according to a recent case-control study done at our Institute. The indoor levels of suspended particles smaller than 10 microns were frequently above 1,000 micrograms/m3 in a rural community in the state of Mexico. This information supports a causal role for biomass smoke for the genesis of several respiratory diseases, representing a potentially public health problem.

[Normal ventilatory response to hypoxia and hypercapnia at an altitude of 2240 meters]

OBJECTIVE

To evaluate the ventilatory response to hypoxia and hypercapnia in healthy residents of Mexico City at 2240 m above sea level.

METHODS

15 healthy subjects, 10 women and 5 men, were studied (mean age 38; range 26-76). All completed one or two tests of ventilatory response to hypoxia and hypercapnia as described by Rebuck-Campbell and Read, respectively. The results were analyzed by linear regression using the minute ventilation as the dependent variable and SaO2 (hypoxia) or PCO2 (hypercapnia) as the independent variables.

RESULTS

Seven subjects had very low or no response to hypoxia. The mean hypoxia slope was 0.7 +/- 0.6 L/min/% (+/- SD) and the hypercapnia slope was 3.0 +/- 1.4 L/min/mmHg. The intercepts were 176 +/- 278 for SaO2 and 3.0 +/- 7 for PCO2.

CONCLUSIONS

A low respiratory response to hypoxia was found in Mexico City Healthy residents. The response to hypercapnia was similar in slope to other studies but had an intercept shifted to lower values. The Mexico City residents showed a behavior typical of patients with chronic hypoxemia or of dwellers at high altitudes.