ABSTRACT
Este artículo investiga el desempeño de los mercados accionarios desarrollados y emergentes, un año antes y después del primer brote de Covid-19. Para lo anterior, se utiliza el Alfa de Jensen, a partir del modelo de 5 factores de Fama & French, estimado por mínimos cuadrados generalizados. Los resultados indican que durante la crisis, los mercados accionarios de Alemania, Austria, España, Holanda, Portugal, Brasil, Chile, Malasia, Rusia, Sudáfrica y Tailandia destruyen valor mientras que China y Corea del Sur presentan un buen desempeño asociado a políticas monetarias y fiscales exitosas, representando así una opción para el refugio de inversionistas globales.Alternate :This article investigates developed and emerging equity markets performance, one year before and one year after the first Covid-19 outbreak. In order to do this, the Jensen's Alpha is used, based on Fama & French five factors model, estimated by generalized least squares. The results indicate that during the crisis, the stock markets of Germany, Austria, Spain, the Netherlands, Portugal, Brazil, Chile, Malaysia, Russia, South Africa and Thailand destroy value while China and South Korea show a superior performance due to the effectiveness of their monetary andfiscal policies, and thus, becoming a relevant option for the refuge of global investors.Alternate :Este documento investiga o desempenho dos mercados bolsistas desenvolvidos e emergentes, um ano antes e um ano depois do primeiro surto de Covid-19. Para este fim, utilizamos o "Alfa de Jensen", baseado no modelo de 5 factores de Fama & French, estimado por mínimos quadrados generalizados. Os resultados indicam que durante a crise, os mercados bolsistas da Alemanha, Austria, Espanha, Holanda, Portugal, Brasil, Chile, Malásia, Russia, África do Sule Tailandia destroem valor, enquanto a China e a Coreia do Sulapresentam um bom desempenho associado apolíticas monetárias efiscais bem sucedidas, representando assim uma opçaopara o refugio dos investidores globais.
ABSTRACT
The SARS-CoV-2 Omicron variant has increased infectivity and immune escape compared with previous variants, and caused the surge of massive COVID-19 waves globally. Despite a vast majority (~90%) of the population of Santa Fe city, Argentina had been vaccinated and/or had been infected by SARS-CoV-2 when Omicron emerged, the epidemic wave that followed its arrival was by far the largest one experienced in the city. A serosurvey conducted prior to the arrival of Omicron allowed to assess the acquired humoral defences preceding the wave and to conduct a longitudinal study to provide individual-level real-world data linking antibody levels and protection against COVID-19 during the wave. A very large proportion of 1455 sampled individuals had immunological memory against COVID-19 at the arrival of Omicron (almost 90%), and about half (48.9%) had high anti-spike immunoglobulin G levels (>200 UI/ml). However, the antibody titres varied greatly among the participants, and such variability depended mainly on the vaccine platform received, on having had COVID-19 previously and on the number of days elapsed since last antigen exposure (vaccine shot or natural infection). A follow-up of 514 participants provided real-world evidence of antibody-mediated protection against COVID-19 during a period of high risk of exposure to an immune-escaping highly transmissible variant. Pre-wave antibody titres were strongly negatively associated with COVID-19 incidence and severity of symptoms during the wave. Also, receiving a vaccine shot during the follow-up period reduced the COVID-19 risk drastically (15-fold). These results highlight the importance of maintaining high defences through vaccination at times of high risk of exposure to immune-escaping variants.