Longevity and Neutralizing Capacity of IgG Antibodies against SARS-CoV-2 Generated by the Application of BNT162b2, AZD1222, Convidecia, Sputnik V, and CoronaVac Vaccines: a Cohort Study in the Mexican Population.

The WHO has approved the use of several vaccines during the COVID-19 pandemic; experience over the last 2 years has indicated that dose demand can only be covered using more than one design. Therefore, having scientific evidence of the performance of the different vaccines applied in a country is highly relevant. In Mexico, 5 vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were used, allowing a cohort study to analyze the generation of anti-S1/S2 IgG antibodies and anti-RBD antibodies with neutralizing activity at 0, 21, 90, and 180 days after vaccination. Five groups of participants were formed on the basis of the type of vaccine received and were divided on the basis of whether they previously had or did not have COVID-19. After completing the vaccination schedule, the seroprevalence was 95.5, 97.5, 81.0, 95.2, and 90.0% (BNT162b2, AZD1222, Convidecia, Sputnik V, and CoronaVac, respectively). Among the participants without COVID-19 prior to vaccination, the largest amount of antibodies in the 90-day period was observed in the BNT162b2 group, and the amount of antibodies in the Sputnik V group decreased the least over time. Even though the percentages of seroconversion obtained in this study were lower than those currently reported in other parts of the world, the tested vaccines are able, in most cases, to induce a good production of IgG antibodies anti-S1/S2 and neutralizing capacity. The fact that there are people who have not produced antibodies during the study leaves open some questions that must be investigated to avoid the appearance of serious cases of COVID-19. IMPORTANCE Since the start of the vaccination programs against COVID-19 in 2020, it was evident that due to global shortages, the demand for the dose required in Mexico could only be covered by acquiring different vaccines. Therefore, determining the effectiveness of these and the longevity of acquired immunity is extremely important in a scenario where SARS-CoV-2 circulation becomes endemic and booster doses are required periodically. Our data reveal significant differences both in the generation of antibodies as well as in their longevity for the vaccines applied in the country but suggest that, in general, the Mexican population can reach a high capacity to neutralize the virus, therefore, regarding less the variant for which they were designed.

Vaccine Effectiveness of CanSino (Adv5-nCoV) Coronavirus Disease 2019 (COVID-19) Vaccine Among Childcare Workers-Mexico, March-December 2021.

BACKGROUND: Beginning in March 2021, Mexico vaccinated childcare workers with a single-dose CanSino Biologics (Adv5-nCoV) coronavirus disease 2019 (COVID-19) vaccine. Although CanSino is currently approved for use in 10 Latin American, Asian, and European countries, little information is available about its vaccine effectiveness (VE). METHODS: We evaluated CanSino VE within a childcare worker cohort that included 1408 childcare facilities. Participants were followed during March-December 2021 and tested through severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction or rapid antigen test if they developed any symptom compatible with COVID-19. Vaccination status was obtained through worker registries. VE was calculated as 100% × (1 - hazard ratio for SARS-CoV-2 infection in fully vaccinated vs unvaccinated participants), using an Andersen-Gill model adjusted for age, sex, state, and local viral circulation. RESULTS: The cohort included 43 925 persons who were mostly (96%) female with a median age of 32 years; 37 646 (86%) were vaccinated with CanSino. During March-December 2021, 2250 (5%) participants had laboratory-confirmed COVID-19, of whom 25 were hospitalized and 6 died. Adjusted VE was 20% (95% confidence interval [CI], 10%-29%) against illness, 76% (95% CI, 42%-90%) against hospitalization, and 94% (95% CI, 66%-99%) against death. VE against illness declined from 48% (95% CI, 33%-61%) after 14-60 days following full vaccination to 20% (95% CI, 9%-31%) after 61-120 days. CONCLUSIONS: CanSino vaccine was effective at preventing COVID-19 illness and highly effective at preventing hospitalization and death. It will be useful to further evaluate duration of protection and assess the value of booster doses to prevent COVID-19 and severe outcomes.

Plataforma CLIMSS como herramienta de alfabetización en salud durante la crisis sanitaria de Covid-19.

OBJETIVO: Describir a la plataforma Cursos en Línea Masivos del IMSS (CLIMSS) como herramienta de alfabetización en salud, a través de la evaluación de la eficiencia terminal, la ganancia de competencias y satisfacción de los usuarios de cursos en línea masivos en el tema de Covid-19. Material y métodos. Se analizaron datos de 20 cursos ofertados entre marzo y octubre de 2020. Se evaluaron las calificaciones pre y pos, el número total de registros, el total de cursos terminados y la satisfacción del usuario. RESULTADOS: Se registraron un total de 4.9 millones de usuarios y 10 millo-nes de inscripciones, en todos los estados de la República mexicana, con una eficiencia terminal de 85%, una ganancia de competencias de 30% y una satisfacción de 9.34 (10). CONCLUSIONES: La plataforma CLIMSS ha mostrado ser una herramienta para la alfabetización en salud con un alcance de millones de mexicanos en temas relacionados con la crisis sanitaria Covid-19.

Leading causes of excess mortality in Mexico during the COVID-19 pandemic 2020-2021: A death certificates study in a middle-income country.

Background: The death toll after SARS-CoV-2 emergence includes deaths directly or indirectly associated with COVID-19. Mexico reported 325,415 excess deaths, 34.4% of them not directly related to COVID-19 in 2020. In this work, we aimed to analyse temporal changes in the distribution of the leading causes of mortality produced by COVID-19 pandemic in Mexico to understand excess mortality not directly related to the virus infection. Methods: We did a longitudinal retrospective study of the leading causes of mortality and their variation with respect to cause-specific expected deaths in Mexico from January 2020 through December 2021 using death certificate information. We fitted a Poisson regression model to predict cause-specific mortality during the pandemic period, based on the 2015-2019 registered mortality. We estimated excess deaths as a weekly difference between expected and observed deaths and added up for the entire period. We expressed all-cause and cause-specific excess mortality as a percentage change with respect to predicted deaths by our model. Findings: COVID-19 was the leading cause of death in 2020-2021 (439,582 deaths). All-cause total excess mortality was 600,590 deaths (38⋅2% [95% CI: 36·0 to 40·4] over expected). The largest increases in cause-specific mortality, occurred in diabetes (36·8% over expected), respiratory infections (33·3%), ischaemic heart diseases (32·5%) and hypertensive diseases (25·0%). The cause-groups that experienced significant decreases with respect to the expected pre-pandemic mortality were infectious and parasitic diseases (-20·8%), skin diseases (-17·5%), non-traffic related accidents (-16·7%) and malignant neoplasm (-5·3%). Interpretation: Mortality from COVID-19 became the first cause of death in 2020-2021, the increase in other causes of death may be explained by changes in the health service utilization patterns caused by hospital conversion or fear of the population using them. Cause-misclassification cannot be ruled out. Funding: This study was funded by Conacyt.

Risk factors for COVID-19 hospitalisations and deaths in Mexican children and adolescents: retrospective cross-sectional study.

OBJECTIVE: To describe the epidemiology and risk factors for hospitalisation and death in Mexican children under 18 years of age with COVID-19. DESIGN: Retrospective, cross-sectional and analytical study. SETTING: Mexican Ministry of Health open databases with COVID-19 cases occurred from 7 March 2020 to 30 September 2021. PARTICIPANTS: Mexican children under 18 years of age with COVID-19. MAIN OUTCOME MEASURES: COVID-19 hospitalisations and deaths were characterised by age group, sex, presence of pneumonia and comorbidities, intubation and intensive care unit admission, and institution that provided medical care. Cumulative incidence, mortality, case fatality rates and ORs for hospitalisation and death were estimated by age group. RESULTS: 5.5% (204 641) of national COVID-19 cases were children under 18 years of age: 2.9% under 1 year, 12.5% from 1 to 5 years, 15% from 6 to 9 years and 69.4% from 10 to 17 years. 4.6% of all cases were hospitalised, from which 54.6% were male, 35.3% were children under 1 year old, 39.6% were adolescents and 34% had pneumonia. Pneumonia developed in 2.3% of cases, from which 50% were adolescents. Case fatality rate was higher in children less than 1 year old (4.2%). Risk analyses showed that male sex (OR 1.16-1.28), history of pneumonia (OR 29.7-65.4), immunosuppression (OR 5.3-42.9), cardiovascular disease (OR 4.4-14.6) and other comorbidities (OR 5.4-19.1), as well as age less than 1 year (OR 20.1, 95% CI 18.8 to 21.4), confer a greater risk of hospitalisation; in addition to comorbidities, age less than 1 year (OR 16.6, 95% CI 14.1 to 19.6), history of pneumonia (OR 14.1-135.1) and being an adolescent from an indigenous community (OR 2.6, 95% CI 1.23 to 5.54, p=0.012) increase the risk of death. CONCLUSIONS: In Mexico, children less than 1 year old with COVID-19 have higher risk of hospitalisation and death than older children. Adolescents with COVID-19 in association with comorbidities develop adverse outcomes more frequently.

Comportamiento epidemiológico de SARS-CoV-2 en población trabajadora afiliada al Instituto Mexicano del Seguro Social.

Objetivo. Describir el comportamiento de la epidemia de SARS-CoV-2 entre los trabajadores afiliados al Instituto Mexicano del Seguro Social (IMSS). Material y métodos. Se analizaron las incapacidades temporales para el trabajo por enfermedades respiratorias (ITT-ER), las hospitalizaciones y defunciones asociadas durante el periodo del 1 marzo al 31 diciembre 2020. Se estimó la tasa de ataque (TA) por SARS-CoV-2, así como los riesgos relativos (RR) de ITT-ER, hos-pitalización y defunción. Resultados. De los trabajadores afiliados al IMSS, 8.8% (n=1 730 334) recibió al menos una ITT-ER. La TA fue mayor en mujeres y en ambos sexos fue menor en el grupo de >60 años. Los RR de hospitalización y defunción fueron mayores en hombres y aumentaron con la edad. Comparado con las ITT-ER de 2015-2019, Durango, Tamaulipas y Nuevo León tuvieron un RR mayor de ITT-ER que el resto del país. Conclusiones. La epidemia de SARS-CoV-2 tuvo repercusiones importantes en los trabajadores afiliados al IMSS; se observó un exceso de ITT-ER de 4.6 veces respecto a la frecuencia esperada y cerca de un millón de casos de SARS-CoV-2. Los datos sugieren que el sistema de ITT-ER puede ser utilizado como elemento adicional para la vigilancia epidemiológica de enfermedades emergentes.

Use of Private Sector Workforce Respiratory Disease Short-Term Disability Claims to Assess SARS-CoV-2, Mexico, 2020.

We examined respiratory disease short-term disability claims submitted to the Mexican Social Security Institute during 2020. A total of 1,631,587 claims were submitted by 19.1 million insured workers. Cumulative incidence (8.5%) was 3.6 times higher than that for January 2015‒December-2019. Workers in healthcare, social assistance, self-service, and retail stores were disproportionately affected.

Criterios de retorno al trabajo y determinación del valor de vulnerabilidad por Covid-19.

Objetivo. Establecer criterios médicos de retorno al trabajo en personal con riesgo de complicaciones por Covid-19. Material y métodos. Se realizó una revisión sistemática para identificar las condiciones y las características clínicas que influyen en el riesgo de desarrollar Covid-19 grave. Resultados. Se ha demostrado incremento del riesgo en obesidad, edad >60 años, diabetes mellitus, hipertensión arterial, enfermedad pulmonar obstructiva crónica, enfermedad cardiovascular, enfermedad renal crónica y cáncer. Solamente en diabetes se ha estudiado si el control previo influye. Se proponen condiciones específicas y el nivel de riesgo epidemiológico para el retorno al trabajo. Conclusiones. El retorno laboral de estos grupos debe priorizarse buscando favorecer el control de la enfermedad, identificando el estado de salud que incrementa el riesgo y protegiendo el derecho al trabajo. Se presentan recomendaciones para guiar la reincorporación al trabajo.

Estimación del exceso de mortalidad por todas las causas durante la pandemia del Covid-19 en México.

 Objetivo. Estimar el exceso de defunciones por todas las causas en México durante 2020. Material y métodos. Se construyó un canal endémico con las defunciones (2015- 2019), estableciendo el umbral epidémico en el percentil 90, y se comparó con las actas de defunción para estimar el exceso de mortalidad. Resultados. A la semana 53, ocurrieron 326 612 defunciones en exceso (45.1%), con un máximo en la semana 28 (98.0%) y un mínimo en la semana 41 (35.2%); después de la semana 4 los hombres (51.3%), principalmente de 45-64 años de edad, sin embargo, en los de 60 años o más ocurrió el mayor nú-mero de defunciones. Conclusión. En México, el exceso de mortalidad ha sido prolongado en comparación con otros países, con alta variabilidad interestatal. Esto podría deberse a las condiciones socioeconómicas y a la alta prevalencia de comorbilidades que aumentan el riesgo de morir en la población mexicana.

Mexico: Lessons learned from the 2009 pandemic that help us fight COVID-19.

In April 2009, Mexican, American, and Canadian authorities announced a novel influenza that became the first pandemic of the century. We report on lessons learned in Mexico. The Mexican Pandemic Influenza Preparedness and Response Plan, developed and implemented since 2005, was a decisive element for the early response. Major lessons-learned were the need for flexible plans that consider different scenarios; the need to continuously strengthen routine surveillance programs and laboratory capacity and strengthen coordination between epidemiological departments, clinicians, and laboratories; maintain strategic stockpiles; establish a fund for public health emergencies; and collaboration among neighboring countries. Mexico responded with immediate reporting and transparency, implemented aggressive control measures and generous sharing of data and samples. Lessons learned induced changes leading to a better response to public health critical events.