Decrease in COVID-19 adverse outcomes in adults during the Delta and Omicron SARS-CoV-2 waves, after vaccination in Mexico.

Mexico, one of the countries severely affected by COVID-19, accumulated more than 5. 1 all-cause excess deaths/1,000 inhabitants and 2.5 COVID-19 confirmed deaths/1,000 inhabitants, in 2 years. In this scenario of high SARS-CoV-2 circulation, we analyzed the effectiveness of the country's vaccination strategy that used 7 different vaccines from around the world, and focused on vaccinating the oldest population first. We analyzed the national dataset published by Mexican health authorities, as a retrospective cohort, separating cases, hospitalizations, deaths and excess deaths by wave and age group. We explored if the vaccination strategy was effective to limit severe COVID-19 during the active outbreaks caused by Delta and Omicron variants. Vaccination of the eldest third of the population reduced COVID-19 hospitalizations, deaths and excess deaths by 46-55% in the third wave driven by Delta SARS-CoV-2. These adverse outcomes dropped 74-85% by the fourth wave driven by Omicron, when all adults had access to vaccines. Vaccine access for the pregnant resulted in 85-90% decrease in COVID-19 fatalities in pregnant individuals and 80% decrease in infants 0 years old by the Omicron wave. In contrast, in the rest of the pediatric population that did not access vaccination before the period analyzed, COVID-19 hospitalizations increased >40% during the Delta and Omicron waves. Our analysis suggests that the vaccination strategy in Mexico has been successful to limit population mortality and decrease severe COVID-19, but children in Mexico still need access to SARS-CoV-2 vaccines to limit severe COVID-19, in particular those 1-4 years old.

[Influence of risk factors on mortality from COVID-19]. / Influencia de factores de riesgo sobre mortalidad por COVID-19.

Background: The main risk factors studied that have an influence on mortality from COVID-19 have so far been inconclusive in the world literature, mainly in relation to the male gender. Objective: To determine which are the main risk factors that influence a higher mortality from COVID-19. Material and methods: A case-control study was conducted, including 1190 patients with positive RT-PCR. The risk factors studied were: gender, age, systemic arterial hypertension (SAH), Diabetes mellitus (DM), obesity, Chronic Obstructive Pulmonary Disease (COPD), asthma, smoking, immunosuppressants, Human Immunodeficiency Virus (HIV), influenza vaccine. In the Group of Cases: they died from COVID-19 (n = 576), while in the Controls group: they survived (n = 614). The statistical plan included cross-tables and multivariate logistic regression model to determine the influence of these risk factors on mortality from COVID-19. Results: We found no statistically significant differences between cases and controls in relation to gender. However, the cases were aged >60 years, SAH, DM, obesity compared to controls. Conclusions: Male gender was not a risk factor for mortality from COVID-19, however, other risk factors such as age over 60 years, being hypertensive, diabetic and obese, were corroborated as such for a higher mortality from COVID-19.

Introducción: los principales factores de riesgo estudiados que tienen influencia sobre la mortalidad por COVID-19 han sido hasta el momento inconclusos en la literatura mundial, principalmente en relación al sexo masculino. Objetivo: determinar cuáles son los principales factores de riesgo que influyen sobre una mayor mortalidad por COVID-19. Material y métodos: se realizó un estudio de casos y controles, incluyendo a 1190 pacientes con PCR-RT positiva. Los factores de riesgo estudiados fueron: sexo, edad, presencia de hipertensión arterial sistémica (HAS), diabetes mellitus (DM), obesidad, enfermedad pulmonar obstructiva crónica (EPOC), asma, tabaquismo, pacientes con ingesta de inmunosupresores, portadores del virus de inmunodeficiencia humana (VIH) y vacuna de influenza. En el grupo de casos fallecieron por COVID-19 (n = 576), mientras que en el de controles sobrevivieron (n = 614). El plan estadístico incluyó tablas cruzadas y modelo de regresión logística multivariable para determinar la influencia de estos factores de riesgo sobre la mortalidad por COVID-19. Resultados: no encontramos diferencias estadísticamente significativas entre casos y controles en relación al sexo. Sin embargo, los casos presentaron: edad > 60 años, HAS, DM y obesidad, en comparación con los controles. Conclusiones: el sexo masculino no fue factor de riesgo para mortalidad por COVID-19, sin embargo, otros factores de riesgo como edad mayor de 60 años, ser hipertenso, diabético y obeso, sí se corroboraron como tales para una mayor mortalidad por COVID-19.