ABSTRACT
Since December 2020, the detection of emerging viral variants of SARS-CoV-2 has attracted the attention of the scientific community and governments at the national and international levels. Some versions of the virus characterized by genetic/evolutionary, epidemiological and/or phenotypic changes have been classified by the WHO as alerts for further monitoring, variants of interest (VOI), or variants of concern (VOC). At the international level, the current situation of variants reflects the sustained advance of the VOC Delta, driving new waves in much of the globe. On the other hand, South America, which exhibits an exceptional landscape of variants dominated by the regionally emerged Gamma (VOC) and Lambda (VOI) begins to face Delta's entry into a dynamic equilibrium of tension between viral evolution, immunity of the population associated with the second wave, and the asymmetry of vaccination campaigns and regional health policies. In this review, we present an update of the latest advances regarding the study of these variants, their potential impact on the epidemiological dynamics and vaccine effectiveness, with a special focus on the Latin American situation of the COVID-19 pandemic, in the second half of 2021.
Desde el mes de diciembre de 2020, la detección de variantes virales emergentes del SARS-CoV-2 ha llamado la atención de la comunidad científica y de los gobiernos a nivel nacional e internacional. Algunas versiones del virus caracterizadas por cambios genéticos, epidemiológicos y/o fenotípicos han sido clasificados por la OMS como variantes para monitoreo adicional, variantes de interés (VOI) o variantes de preocupación (VOC). A nivel internacional la situación actual de variantes refleja el avance sostenido de la VOC Delta, impulsando nuevas olas de infecciones en gran parte del mundo. Por otro lado, América del Sur exhibe un paisaje particular de linajes circulantes, dominado por las variantes de emergencia regional Gamma (VOC) y Lambda (VOI). Esta región empieza a afrontar el ingreso de Delta en un equilibrio dinámico de tensión entre la evolución viral, la inmunidad adquirida de la población asociada a la segunda ola, y la asimetría en las campañas de vacunación y en las políticas sanitarias regionales. En esta revisión presentamos una actualización de los últimos avances relativos al estudio de las variantes virales emergentes del SARS-CoV-2, su potencial impacto en la dinámica epidemiológica y en la efectividad vacunal, con especial foco en la situación regional latinoamericana de pandemia de la COVID-19 en el segundo semestre de 2021.
ABSTRACT
Objetivo: Conocer la efectividad de la vacuna de la gripe de la temporada 2018/2019 para la prevención de casos graves de gripe en un hospital terciario. Método: Estudio de casos y controles. Se incluyeron todos los pacientes hospitalizados con gripe confirmada por laboratorio durante la temporada 2018/2019. Los que cumplieron criterios de caso grave de gripe (neumonía, fallo multiorgánico, shock séptico, ingreso en la unidad de cuidados intensivos o muerte) se consideraron caso. Los que no cumplían criterios de gravedad se consideraron controles. Se calculó la efectividad de la vacuna (EV) cruda y ajustada (para prevenir casos graves de gripe), así como su intervalo de confianza del 95%, mediante la fórmula EV = (1 − odds ratio) × 100. Resultados: La efectividad ajustada por grupo de edad y comorbilidad fue del 60,7% (20,5-80,5). En el análisis ajustado y restringido a cada sexo, grupo de edad y presencia de comorbilidad, la vacuna de la gripe tuvo un efecto positivo en todos los grupos y categorías, siendo la efectividad del 55,0% (2,6-79,2) en el grupo de edad de 65 años o más. Conclusiones: La vacunación antigripal redujo la gravedad de la gripe en los pacientes hospitalizados. Estos hallazgos deberían tenerse en cuenta para mejorar las estrategias de vacunación y alcanzar mejores coberturas vacunales en la población de riesgo, con la finalidad no solo de disminuir los casos de gripe, sino también su gravedad. (AU)
Objective: To know the effectiveness of the 2018/2019 flu vaccine for the prevention of severe cases of flu in a tertiary hospital. Method: Case-control study. We included all patients hospitalized with influenza confirmed by laboratory during 2018/2019 season. Those who met the criteria of severe case of influenza (pneumonia, multiorgan failure, septic shock, ICU admission or death) were considered as cases. Non severe cases of influenza were included in the control group. We calculated the effectiveness of the raw and adjusted vaccine (to prevent severe cases of influenza) and its 95% confidence interval using formula VE = (1 − odds ratio) × 100. Results: Effectiveness of flu vaccine adjusted by age group and comorbidities was 60.7% (20.5-80.5). In the analysis adjusted and restricted to each sex, age group and presence of comorbidities, the influenza vaccine had a positive effect in all groups and categories, with effectiveness in the age group 65 years or more being 55.0% (2.6-79.2). Conclusions: Flu vaccination reduced the severity of influenza in hospitalized patients. These findings should be taken into account to improve vaccination strategies and achieve better vaccination coverage in the high-risk population in order not only to decrease flu cases, but also their severity. (AU)
Subject(s)
Humans , Influenza Vaccines , Influenza B virus , Influenza A Virus, H3N2 Subtype , Case-Control Studies , Aging , SeasonsABSTRACT
OBJECTIVE: To know the effectiveness of the 2018/2019 flu vaccine for the prevention of severe cases of flu in a tertiary hospital. METHOD: Case-control study. We included all patients hospitalized with influenza confirmed by laboratory during 2018/2019 season. Those who met the criteria of severe case of influenza (pneumonia, multiorgan failure, septic shock, ICU admission or death) were considered as cases. Non severe cases of influenza were included in the control group. We calculated the effectiveness of the raw and adjusted vaccine (to prevent severe cases of influenza) and its 95% confidence interval using formula VE=(1-odds ratio)×100. RESULTS: Effectiveness of flu vaccine adjusted by age group and comorbidities was 60.7% (20.5-80.5). In the analysis adjusted and restricted to each sex, age group and presence of comorbidities, the influenza vaccine had a positive effect in all groups and categories, with effectiveness in the age group 65 years or more being 55.0% (2.6-79.2). CONCLUSIONS: Flu vaccination reduced the severity of influenza in hospitalized patients. These findings should be taken into account to improve vaccination strategies and achieve better vaccination coverage in the high-risk population in order not only to decrease flu cases, but also their severity.
