ABSTRACT
Objetivo: El objetivo del presente estudio fue proporcionar estimaciones a nivel estatal de la efectividad en el mundo real para reducir las probabilidades de un resultado primario (infección sintomática por COVID-19) y dos resultados secundarios (hospitalización e infección grave por COVID-19) por cuatro vacunas BNT162b2 (Pfizer- BioNTech), ChAdOx1 (AstraZeneca), Ad5-nCoV (CanSinoBIO) y CoronaVac (Sinovac Life Sciences), utilizados en el noreste de México. Diseño: Realizamos un estudio de casos y controles y analizamos los datos de vigilancia en todo el estado desde diciembre de 2020 hasta agosto de 2021;Emplazamiento: Atención primaria y hospitalización. Participantes: Se aplicaron dos criterios de inclusión, edad ≥ 18 años y tener prueba de RT-PCR tiempo real o una prueba rápida para la detección de antígeno en muestras posnasales (N = 164.052). La vacunación se consideró completa si habían transcurrido al menos 14 días desde la aplicación de la dosis única o segunda y el inicio de la sintomatología. Intervenciones: No aplica Mediciones Principales: Se calcularon los puntos e intervalos de confianza (IC) del 95% de la efectividad de la vacuna por tipo de vacuna utilizando la fórmula 1: razón de probabilidades, ajustada por sexo y edad. Resultados: Vacunación completa que ofrece desde ninguna (CoronaVac - Sinovac) hasta 75% (95%IC 71, 77) (BNT162b2 -Pfizer) de efectividad en la reducción de la infección sintomática por COVID-19, independientemente del sexo y la edad. El esquema completo con ChAdOx1 (AstraZeneca) alcanzó la máxima efectividad en hospitalización (80%, 95% IC 69, 87) y el esquema completo con BNT162b2 (Pfizer) la máxima efectividad en gravedad (81%, 95% IC 64, 90). Conclusiones: Se necesitan más estudios para comparar los beneficios de las diferentes vacunas y guiar a los responsables en formulación de políticas a seleccionar la mejor opción para su población.
ABSTRACT
OBJECTIVE: The objective of the present study was to provide statewide estimates of real-world effectiveness in reducing the odds of one primary (symptomatic COVID-19 infection) and two secondary outcomes (hospitalization and severe COVID-19 infection) by four vaccines BNT162b2 (Pfizer-BioNTech), ChAdOx1 (AstraZeneca), Ad5-nCoV (CanSinoBIO), and CoronaVac (Sinovac Life Sciences), used in Northeast Mexico. DESIGN: We conducted a test-negative case-control study and analyzed statewide surveillance data from December 2020 to August 2021. SITE: Primary attention and hospitalization. PARTICIPANTS: Two inclusion criteria were applied, age≥18 years and having a real-time reverse-transcriptase-polymerase-chain-reaction assay or a rapid test for antigen detection in postnasal samples (N=164,052). The vaccination was considered complete if at least 14 days had passed since the application of the single or second dose and the beginning of symptomatology. INTERVENTIONS: Does not apply. MAIN MEASUREMENTS: Point and 95% confidence intervals (CI) of vaccine effectiveness were calculated per type of vaccine using the formula 1 - odds ratio, adjusted by sex and age. RESULTS: Complete vaccination offered from none (CoronaVac - Sinovac) to 75% (95%CI 71, 77) (BNT162b2 - Pfizer) effectiveness in reducing symptomatic COVID-19 infection, regardless of sex and age. The fully ChAdOx1 (AstraZeneca) scheme reached the maximum effectiveness in hospitalization (80%, 95%CI 69, 87) and the fully BNT162b2 (Pfizer) scheme the maximum effectiveness in severity (81%, 95%CI 64, 90). CONCLUSIONS: More studies are needed to compare benefits of different vaccines and guide policy makers select the best option for their population.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Adolescent , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , BNT162 Vaccine , Case-Control Studies , Mexico/epidemiologyABSTRACT
Population-based immunoglobulin G (IgG) seroprevalence studies in asymptomatic individuals in Latin America are scarce. The objective of the study was to estimate the prevalence and geographic distribution of IgG antibodies induced by natural SARS-CoV-2 infection in asymptomatic adults, 5-8 months after the first case was reported in a northeastern state of Mexico. This was a population-based cross-sectional study carried out in Nuevo Leon during August-November 2020. Individuals ≥18 years with no previous diagnosis or symptoms suggestive of COVID-19 were consecutively screened in one of the busiest subway stations. Also, a search for eligible individuals was done from house-to-house, after selecting densely populated geographic sectors of each of the municipalities of the metropolitan area (n = 4495). The IgG antibodies to SARS-CoV-2 nucleocapsid protein were analyzed. The IgG antibody positivity rate was 27.1% (95% confidence interval [CI]: 25.8, 28.4); there were no differences by sex or age (p > 0.05). Analysis by month showed a gradual increase from 11.9% (August) to 31.9% (November); Week 39 had the highest positivity rate (42.2%, 95% CI: 34.2, 50.7). Most people did not have evidence of previous SARS-CoV-2 infection. Preventive measures and promotion of the COVID-19 vaccine should be strengthened.