Browsing by Author "García Salum, Tamara Cristal"

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    Long-lasting neutralizing antibody responses in SARS-CoV-2 seropositive individuals are robustly boosted by immunization with the CoronaVac and BNT162b2 vaccines
    (2021) Muena, Nicolás A.; García Salum, Tamara Cristal; Pardo Roa, Catalina; Serrano García, Eileen Francisca; Levicán Asenjo, Jorge Enrique; Avendaño, María José; Almonacid Cárdenas, Leonardo Iván; Valenzuela Galaz, Gonzalo Hernán; Poblete Cárdenas, Estefany Aracely; Strohmeier, Shirin; Salinas Ortíz, Erick David; Haslwanter, Denise; Dieterle, Maria Eugenia; Jangra, Rohit K.; Chandran, Kartik; González, Claudia; Riquelme Pérez, Arnoldo Javier; Krammer, Florian; Tischler, Nicole D.; Medina, Rafael
    The durability of circulating neutralizing antibody (nAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their boosting by vaccination remains to be defined. We show that outpatient and hospitalized SARS-CoV-2 seropositive individuals mount a robust neutralizing antibody (nAb) response that peaks at days 23 and 27 post-symptom onset, respectively. Although nAb titers remained higher in hospitalized patients, both study groups showed long-lasting nAb responses that can persist for up to 12 months after natural infection. These nAb responses in previously seropositive individuals can be significantly boosted through immunization with two doses of the CoronaVac (Sinovac) or one dose of the BNT162b2 (BioNTech/Pfizer) vaccines, suggesting a substantial induction of B cell memory responses. Noteworthy, three obese previously seropositive individuals failed to mount a booster response upon vaccination, warranting further studies in this population. Immunization of naïve individuals with two doses of the CoronaVac vaccine or one dose of the BNT162b2 vaccine elicited similar levels of nAbs compared to seropositive individuals 4.2 to 13.3 months post-infection with SARS-CoV-2. Thus, this preliminary evidence suggests that both, seropositive and naïve individuals, require two doses of CoronaVac to ensure the induction of robust nAb titers.
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    Respuesta inmune humoral inducida por la vacuna influenza en niños con diagnóstico de leucemia linfoblástica aguda
    (Sociedad Chilena de Infectología, 2020) Cerda Valenzuela, Carolina Angélica; Martínez Valdebenito, Constanza Pamela; Barriga Cifuentes, Francisco José; Contreras, Marcela; Vidal, Marcela; Moreno, Rosa; Claverie, Ximena; Contreras, Paola; Huenuman, Lesly; García Salum, Tamara Cristal; Rathnasighe, Raveen; Medina Silva, Rafael Andrés; Ferrés Garrido, Marcela Viviana; Le Corre Pérez, Monique Nicole
    Background: Patients with acute lymphoblastic leukemia (ALL) have high risk of severe influenza infection and vaccination is highly recommended. The immunogenicity and effectiveness of vaccination are lower than in healthy people. Aim: To evaluate the immune response induced by influenza vaccine in children with ALL and observe effectiveness. Method: Children with ALL in maintenance phase and healthy children were recruited. Blood samples were taken at vaccination day (D0) and at day 28 (D28). Humeral response was evaluated by hemaglutination inhibition test (HAI) against H1N1. Patients were followed up for one year, clinical data and influenza episodes were recorded. Results: 34 children with ALL and 9 healthy children were included. Concerning HAI on D28, 12/34 patients and 5/8 healthy children had titers >= 1/40, with seroprotection rates of 35 and 63% respectively. Seroprotected children were older than non-seroprotected ones. During follow-up, only 3 patients non seroprotected, presented influenza infection, without oxygen supplementation or critical care support. Discussion: Children with ALL had a lower seroprotection rate than healthy children. Nevertheless, none of the seroprotected children presented influenza infection, reinforcing the annual vaccination recommendation.