Browsing by Author "Ormazábal, Ivana"

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    Clinical and epidemiological characteristics of SARS-CoV-2 virus in ambulatory children under 2 years old
    (2022) Pérez, Carolina A.; Ormazábal, Ivana; Pérez Valenzuela, Javier; Araya del Pino, Andrea Paz; Medina, Rafael; Perret Pérez, Cecilia
    Background: SARS-CoV-2 is an emerging virus that has mainly affected adults; hence, most clinical information has been derived from that population. Most pediatric cases are mild and with nonspecific symptoms requiring outpatient management. Children are a major source of spread for most traditional respiratory viruses. Their role in SARS-CoV-2 transmission was thought to be relevant. Children under the age of two comprise a group that is more susceptible to infection since vaccines have not been approved for them until recently. The knowledge of clinical manifestation of COVID-19 in young children is scarce. Objectives: To describe the clinical, epidemiological, and demographic characteristics of children under 2 years old with confirmed COVID-19, who did not require hospitalization. Methods: This descriptive study was performed from May, 2020 to June, 2021. Children ages 0-2 years with COVID-19, confirmed by transcriptase-polymerase chain reaction assay that were performed in laboratories of the Red de Salud UC CHRISTUS Health Network, were selected to be contacted. If the parents accepted participating and their children were not hospitalized, a survey was sent to the patients' caregivers. Results: Of the 242 cases, 159 caregivers answered the survey (65.7%). The median age of the subjects was 14 months, and 53.5% were males. Fifty percent had comorbidities, of which one third corresponded to atopy. Ninety eight percent were secondary cases. Most of them were infected within their households (81%). The most frequent sources were their parents, followed by their grandparents. The most common symptom was fever (78%) followed by irritability (67.3%), rhinorrhea (66%), and fatigue (64.8%). Infants less than 6 months old more often presented with conjunctival congestion and less loss of appetite compared to older children (p < 0.05). Conclusions: This study provides valuable insights regarding COVID-19 in ambulatory young children. Most cases of SARS-CoV-2 infection in children under 2 years old do not require hospitalization. There was a slight male predominance, and the majority had been infected within their households. SARS-CoV-2 infection should be suspected in children under 2 years old presenting with fever, irritability, fatigue, and rhinorrhea. Children with positive household contacts and fever should also be tested for COVID-19.
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    Influence of SARS-CoV-2 mRNA Vaccine Booster among Cancer Patients on Active Treatment Previously Immunized with Inactivated versus mRNA Vaccines: A Prospective Cohort Study
    (2023) Mondaca Contreras, Sebastián Patricio; Walbaum, Benjamín; Corre, Nicole Le; Ferrés Garrido, Marcela Viviana; Valdés, Alejandro; Martínez-Valdebenito, Constanza; Ruiz-Tagle, Cinthya; Macanas Pirard, Patricia; Ross, Patricio; Cisternas, Betzabé; Pérez, Patricia; Cabrera, Olivia; Cerda, Valentina; Ormazábal, Ivana; Barrera Vásquez, Aldo Vincen; Prado, María E.; Venegas, María I.; Palma, Silvia; Broekhuizen, Richard; Kalergis, Alexis; Bueno, Susan M.; Espinoza, Manuel A.; Balcells Marty, María Elvira; Nervi Nattero, Bruno
    Cancer patients on chemotherapy have a lower immune response to SARS-CoV-2 vaccines. Therefore, through a prospective cohort study of patients with solid tumors receiving chemotherapy, we aimed to determine the immunogenicity of an mRNA vaccine booster (BNT162b2) among patients previously immunized with an inactivated (CoronaVac) or homologous (BNT162b2) SARS-CoV-2 vaccine. The primary outcome was the proportion of patients with anti-SARS-CoV-2 neutralizing antibody (NAb) seropositivity at 8–12 weeks post-booster. The secondary end points included IgG antibody (TAb) seropositivity and specific T-cell responses. A total of 109 patients were included. Eighty-four (77%) had heterologous vaccine schedules (two doses of CoronaVac followed by the BNT162b2 booster) and twenty-five had (23%) homologous vaccine schedules (three doses of BNT162b2). IgG antibody positivity for the homologous and heterologous regimen were 100% and 96% (p = 0.338), whereas NAb positivity reached 100% and 92% (p = 0.13), respectively. Absolute NAb positivity and Tab levels were associated with the homologous schedule (with a beta coefficient of 0.26 with p = 0.027 and a geometric mean ratio 1.41 with p = 0.044, respectively). Both the homologous and heterologous vaccine regimens elicited a strong humoral and cellular response after the BNT162b2 booster. The homologous regimen was associated with higher NAb positivity and Tab levels after adjusting for relevant covariates.