Browsing by Author "Najera, Manuel"

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    Age as Risk Factor for Death from Pandemic (H1N1) 2009, Chile
    (CENTERS DISEASE CONTROL, 2011) Dabanch, Jeannette; Perret, Cecilia; Najera, Manuel; Gonzalez, Claudia; Guerrero, Andrea; Olea, Andrea; Fasce, Rodrigo; Morales, Cecilia; Vega, Jeanette; Advisory Comm Chilean Minist Hlth
    Pandemic (H1N1) 2009 affected Chile during the winter of 2009. The hospitalization rate was 0.56% overall and 3.47% for persons >= 60 years of age at risk for severe disease and death independent of concurrent conditions. Age >= 60 years was the major risk factor for death from pandemic (H1N1) 2009.
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    Effectiveness and duration of a second COVID-19 vaccine booster
    (2022) Jara, Alejandro; Cuadrado, Cristobal; Undurraga Fourcade, Eduardo Andrés; García, Christian; Najera, Manuel; Bertoglia, María Paz; Vergara, Verónica; Fernández, Jorge; García, Heriberto; Araos, Rafael
    Using a prospective national cohort of 3.75 million individuals aged 20 or older, we evaluated the effectiveness against COVID-19 related ICU admissions and death of mRNA-based second vaccine boosters for four different three-dose background regimes: BNT162b2 primary series plus a homologous booster, and CoronaVac primary series plus an mRNA booster, a homologous booster, and a ChAdOx-1 booster. We estimated the vaccine effectiveness weekly from February 14 to August 15, 2022, by estimating hazard ratios of immunization over non-vaccination, accounting for relevant confounders. The overall adjusted effectiveness of a second mRNA booster shot was 88.2% (95%CI, 86.2-89.9) and 90.5% (95%CI 89.4-91.4) against ICU admissions and death, respectively. Vaccine effectiveness showed a mild decrease for all regimens and outcomes, probably associated with the introduction of BA.4 and BA.5 Omicron sub-lineages and immunity waning. The duration of effectiveness suggests that no additional boosters are needed six months following a second booster shot.