All FSI News News October 29, 2021

COVID-19 and End-of-Year Holiday Gatherings in Mexico City

Mexico City was hit hard by COVID-19 at the end of 2020, which may have been due in part to big holiday gatherings and public festivals. The SHP modeling team is warning that the sprawling metropolitan area could face another winter surge — by offering evidence of how the numbers spiked after the holidays and into the new year.
Christmas decorations in Mexico City
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With the 2021-22 holiday season approaching, a team of Stanford researchers who use data analyses and simulation models to make COVID-19 projections is concerned that if end-of-year’s festivities in Mexico City Metropolitan Area (MCMA) are anything like the last, the city could once again experience a spike in deaths and hospital overcapacity.

These end-of-year holidays are traditionally marked by big family gatherings and crowded festivals in Mexico. Those traditions among the more than 20 million residents in MCMA could create perfect storm conditions for another winter surge.

By mid-December 2020, Mexico had the 12th highest number of confirmed COVID-19 cases in the world and the second-largest number of deaths in Latin America. Today, Mexico has the 16th highest number of coronavirus cases in the world — and ranks fourth in deaths, behind the United States, Brazil, and India.

In a study conducted last year to inform policy that was recently published in the journal MDM Policy and Practice, the SC-COSMO Consortium projected that following high levels of holiday contacts last year — even with no in-person schooling — the MCMA would have some 900,000 additional COVID cases by March 2021. They also estimated that hospitalization demand would peak at 26,000 by January 25, 2021, with a 97% chance of exceeding the 9,667 hospital beds prepared for coronavirus patients.

That’s exactly what happened. The peak in cases occurred during the third week of January, 2021, at which time COVID-19 hospitalizations largely reached capacity.

“Unfortunately, social distancing and non-pharmaceutical interventions were implemented late and not comprehensively, so we saw a high COVID-19 death rate and spiking hospital demand  at the beginning of 2021 in the metropolitan area,” said Fernando Alarid-Escudero, an assistant professor at the Center for Research and Teaching in Economics (CIDE) in Mexico and lead author on the study. He is also a co-founder of the SC-COSMO Consortium, which has conducted dozens of studies to inform jurisdictions including Mexico City and the state of California as well as California’s correctional facilities regarding planning for and mitigating COVID-19.

Simulation models and policy analyses are important tools. They can support policymakers and public health officials faced with uncertain and difficult decisions.
Fernando Alarid-Escudero
Assistant Professor at the Center for Research and Teaching in Economics in Mexico

“The question now is, how will it play out in the 2021 end-of-year holiday season. Our study demonstrates how intertwined COVID-19 policies can be in different spheres,” said Jeremy Goldhaber-Fiebert, an professor of health policy at Stanford and senior author of the MDM study and also a co-founder of the SC-COSMO Consortium. “The study’s projections into 2021 — especially when compared to what actually happened — suggest that existing policies and levels of preventive behaviors like physical distancing and use of non-pharmaceutical interventions around the end-of-year holidays were not sufficient to address a large surge in cases in MCMA.”

Goldhaber-Fiebert noted insufficient control in Mexico City resulted in two key outcomes.

“First, health-care outcomes were worse than they could have been -- there were more hospitalizations and deaths than might have been otherwise possible,” said Goldhaber-Fiebert. “Second, failure to adequately control transmission and cases from this wave made the safe resumption of in-person schooling extremely challenging, forcing difficult trade-offs between public health and educational benefits.”

The SC-COSMO Consortium has done work on numerous states in Mexico, including MCMA, and the State of Hidalgo. Alarid-Escudero said that working with Goldhaber-Fiebert and other members of the consortium has been fundamental to the advice given to public health officials in Mexico.

“Simulation models and policy analyses are important tools,” said Alarid-Escudero, “They can support policymakers and public health officials faced with uncertain and difficult decisions.”

Fernando Alarid-Escudero

Assistant Professor, Center for Research and Teaching in Economics
Statistical & analytical modeling to prevent, control & treat diseases
Fernando Alarid-Escudero

Jeremy Goldhaber-Fiebert

Professor of Health Policy
Decision science, simulation modeling & cost-effectiveness analysis
jeremy fisch headshot

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