[Risk factors for COVID-19 severe complications comparing three major epidemiological waves: An approach from primary health care in Mexico].

Objectives: To describe the association between chronic noncommunicable diseases and age with hospitalization, death and severe clinical outcomes for COVID-19 in confirmed cases within the mexican population, comparing the first three epidemiological waves of the pandemic in Mexico.

Design: We performed an analysis using Mexico's Government Epidemiological Surveillance System database for COVID-19.

Emplacement: Mexico's Epidemiological Surveillance System for Respiratory Diseases.

[Not Available].

Objetivo: Analizar la asociación de la concentración de con-taminantes atmosféricos y los indicadores epidemiológicos de Covid-19 en la Zona Metropolitana del Valle de México (ZMVM). Material y métodos. Se diseñó un estudio epidemiológico ecológico.