Mexican Social Security Institute (IMSS) Pandemic Workforce Administrative Cohort (IMPACT): design and descriptive estimates of surveillance-detected COVID-19 outcomes and primary-series vaccination coverage.
8 affiliations
- 1Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada.
- 2Occupational Health Research Unit, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
- 3Faculty of Pharmacy, Université de Montréal, Montreal, Quebec, Canada.
- 4Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montreal, Quebec, Canada.
- 5Department of Social and Preventive Medicine, Université Laval, Quebec City, Quebec, Canada.
- 6Population Health and Optimal Health Practices Axis, Research Center of the CHU de Québec - Université Laval, Quebec City, Quebec, Canada.
- 7Occupational Health Coordination, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
- 8Directorate of Economic and Social Benefits, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
Abstract
Introduction
The COVID-19 pandemic placed unprecedented strain on health systems and their workers. In Mexico, the health-system workforce faced this crisis amid major population health, socioeconomic and institutional constraints. Despite these challenges, no population-level research platform existed to support pandemic-related research on this occupational group. In this study, we describe the design of the Mexican Social Security Institute (IMSS) Pandemic Workforce Administrative Cohort (IMPACT) and, as its first application, characterise primary-series vaccination coverage and surveillance-detected COVID-19 outcomes.Methods
Using IMSS payroll records, we identified workers employed during the pandemic and linked this roster to additional real-world data sources. Guided by relevant literature, we operationalised variables for baseline characteristics, vaccination status and surveillance-detected COVID-19 outcomes. We defined two analytical cohorts from these linked data (follow-up end: 9 May 2023): a closed cohort comprising workers already employed at pandemic onset and an open cohort that additionally included subsequent hires. Vaccination was assessed in the closed cohort whereas COVID-19 outcomes were assessed in both. Analyses were conducted overall and stratified by work-unit type, job category, department and geography.Results
In the closed cohort (n=434 655), first-dose and full-series coverage exceeded 70% by days 123 and 169 of the rollout, reaching 93.4% (95% CI 93.3% to 93.5%) and 84.0% (95% CI 83.8% to 84.1%) by follow-up end. Over this period, cumulative incidence was 55.4% (95% CI 55.2% to 55.5%) for infection, 0.99% (95% CI 0.96% to 1.02%) for hospitalisation and 0.22% (95% CI 0.21% to 0.24%) for death. In the open cohort (n=506 995), incidence rates per 100 000 person-days were 60.7 (95% CI 60.6 to 60.9) for infection, 0.80 (95% CI 0.77 to 0.83) for hospitalisation and 0.18 (95% CI 0.15 to 0.20) for death. Unstandardised estimates varied substantially across strata.Conclusions
Among workers employed at pandemic onset, vaccination coverage was high, particularly for first doses. Although surveillance-detected infection was common, severe outcomes were infrequently recorded. Stratified analyses identified vaccination gaps and high-burden strata warranting further investigation. IMPACT provides a valuable platform for policy-relevant research into this workforce.
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BibTeX
@article{ortizbrizuela2026mexican,
title = {{Mexican Social Security Institute (IMSS) Pandemic Workforce Administrative Cohort (IMPACT): design and descriptive estimates of surveillance-detected COVID-19 outcomes and primary-series vaccination coverage.}},
author = {Edgar Ortiz-Brizuela and Mireille E Schnitzer and Denis Talbot and Gabriel Alejandro Real Ornelas and Rebeca Velasco Reyna and Mauricio Hernandez-Avila and Mabel Carabali},
journal = {BMJ public health},
year = {2026},
month = oct,
doi = {10.1136/bmjph-2025-004581},
url = {https://europepmc.org/article/MED/42948618},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Mexican Social Security Institute (IMSS) Pandemic Workforce Administrative Cohort (IMPACT): design and descriptive estimates of surveillance-detected COVID-19 outcomes and primary-series vaccination coverage.
AU - Edgar Ortiz-Brizuela
AU - Mireille E Schnitzer
AU - Denis Talbot
AU - Gabriel Alejandro Real Ornelas
AU - Rebeca Velasco Reyna
AU - Mauricio Hernandez-Avila
AU - Mabel Carabali
PY - 2026
DA - 2026/10/20
JO - BMJ public health
DO - 10.1136/bmjph-2025-004581
UR - https://europepmc.org/article/MED/42948618
AB - Introduction The COVID-19 pandemic placed unprecedented strain on health systems and their workers. In Mexico, the health-system workforce faced this crisis amid major population health, socioeconomic and institutional constraints. Despite these challenges, no population-level research platform existed to support pandemic-related research on this occupational group. In this study, we describe the design of the Mexican Social Security Institute (IMSS) Pandemic Workforce Administrative Cohort (IMPACT) and, as its first application, characterise primary-series vaccination coverage and surveillance-detected COVID-19 outcomes.Methods Using IMSS payroll records, we identified workers employed during the pandemic and linked this roster to additional real-world data sources. Guided by relevant literature, we operationalised variables for baseline characteristics, vaccination status and surveillance-detected COVID-19 outcomes. We defined two analytical cohorts from these linked data (follow-up end: 9 May 2023): a closed cohort comprising workers already employed at pandemic onset and an open cohort that additionally included subsequent hires. Vaccination was assessed in the closed cohort whereas COVID-19 outcomes were assessed in both. Analyses were conducted overall and stratified by work-unit type, job category, department and geography.Results In the closed cohort (n=434 655), first-dose and full-series coverage exceeded 70% by days 123 and 169 of the rollout, reaching 93.4% (95% CI 93.3% to 93.5%) and 84.0% (95% CI 83.8% to 84.1%) by follow-up end. Over this period, cumulative incidence was 55.4% (95% CI 55.2% to 55.5%) for infection, 0.99% (95% CI 0.96% to 1.02%) for hospitalisation and 0.22% (95% CI 0.21% to 0.24%) for death. In the open cohort (n=506 995), incidence rates per 100 000 person-days were 60.7 (95% CI 60.6 to 60.9) for infection, 0.80 (95% CI 0.77 to 0.83) for hospitalisation and 0.18 (95% CI 0.15 to 0.20) for death. Unstandardised estimates varied substantially across strata.Conclusions Among workers employed at pandemic onset, vaccination coverage was high, particularly for first doses. Although surveillance-detected infection was common, severe outcomes were infrequently recorded. Stratified analyses identified vaccination gaps and high-burden strata warranting further investigation. IMPACT provides a valuable platform for policy-relevant research into this workforce.
SN - 2753-4294
ER -