RUBILAR RAMIREZ, PAOLA ANDREA
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RUBILAR RAMIREZ, PAOLA ANDREA
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pramirez@udd.cl
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57031794200

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Dataset - Immunization and SARS-CoV-2 Antibody Seroprevalence in a Country with High Vaccination Coverage: Lessons from Chile

2022 , AGUILERA SANHUEZA, XIMENA PAZ , GONZALEZ WIEDMAIER, CLAUDIA MARTA , APABLAZA SALINAS, MAURICIO IVÁN , RUBILAR RAMIREZ, PAOLA ANDREA , CORTES SALINAS, LINA JIMENA

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First wave of SARS-CoV-2 in Santiago Chile: Seroprevalence, asymptomatic infection and infection fatality rate

2022 , VIAL CLARO, PABLO AGUSTIN , GONZALEZ WIEDMAIER, CLAUDIA MARTA , APABLAZA SALINAS, MAURICIO IVÁN , VIAL COX, MARIA CECILIA , Gloria Icaza , ARAOS BRALIC, RAFAEL IGNACIO , RUBILAR RAMIREZ, PAOLA , Juan Correa , Andrei Florea , PEREZ ACUÑA, CLAUDIA VERONICA , Paula Concha , Diego Bastías , María Paz Errázuriz , Ruth Pérez , M.Estela Lavín , OLEA NORMANDIN, ANDREA MARIA , MUNITA SEPULVEDA, JOSE MANUEL , AGUILERA SANHUEZA, XIMENA PAZ , Francisco Guzmán , Eugenio Guzmán

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SARS-CoV-2 Neutralizing Antibodies in Chile after a Vaccination Campaign with Five Different Schemes

2022 , AGUILERA SANHUEZA, XIMENA PAZ , HORMAZABAL CASTILLO, JUAN PATRICIO , VIAL COX, MARIA CECILIA , CORTES SALINAS, LINA JIMENA , GONZALEZ WIEDMAIER, CLAUDIA MARTA , RUBILAR RAMIREZ, PAOLA , APABLAZA SALINAS, MAURICIO IVÁN , Muriel Ramírez-Santana , Gloria Icaza , Loreto Nuñez-Franz , Rubén Quezada-Gate , Macarena Said , PEREZ ACUÑA, CLAUDIA VERONICA , CASTILLO LABORDE, CARLA CECILIA , Carolina Sacristán Ramírez , VIAL CLARO, PABLO AGUSTIN

Using levels of neutralizing antibodies (nAbs), we evaluate the successful Chilean SARS-CoV-2 vaccine campaign, which combines different vaccine technologies and heterologous boosters. From a population-based study performed in November 2021, we randomly selected 120 seropositive individuals, organized into six groups of positive samples (20 subjects each) according to natural infection history and the five most frequent vaccination schemes. We conclude that the booster dose, regardless of vaccine technology or natural infection, and mRNA vaccines significantly improve nAbs response.

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Seroprevalence of Natural and Acquired Immunity against the SARS-CoV-2 Virus in a Population Cohort from Two Chilean Cities, 2020–2022

2023 , Loreto Núñez-Franz , Muriel Ramírez-Santana , RUBILAR RAMIREZ, PAOLA , Macarena Said , VIAL COX, MARIA CECILIA , Luis Canales , GONZALEZ WIEDMAIER, CLAUDIA MARTA , APABLAZA SALINAS, MAURICIO IVÁN , Gloria Icaza , HORMAZABAL CASTILLO, JUAN PATRICIO , Rubén Quezada-Gaete , VIAL CLARO, PABLO AGUSTIN , Kathya Olivares , CORTES SALINAS, LINA JIMENA , AGUILERA SANHUEZA, XIMENA PAZ

Background: Chile has achieved the highest coverage for vaccines against the SARS-CoV-2 virus worldwide. Objective: To assess the progression of immunity (natural and acquired by vaccine) in a cohort from two Chilean cities. Methods: Individuals (n = 386) who participated in three phases of population-based serial prevalence studies were included (2020–2021 and 2022). Presence of SARS-CoV-2 antibodies was measured in serum. Data including time of vaccination and type of vaccine received were analysed with descriptive statistics. Results: Seroprevalence was 3.6% in the first round and increased to 96.9% in the second and 98.7% in the third. In the third round, 75% of individuals who had received the basal full scheme were seropositive at 180 days or more since their last dose; 98% of individuals who received one booster dose were seropositive at 180 days or more, and 100% participants who received two boosters were seropositive, regardless of time since their last dose. Participants receiving mRNA vaccines had higher seroprevalence rates over time. Conclusions: The high vaccination coverage in Chile enabled the population to maintain high levels of antibodies. Vaccination boosters are essential to maintain immunity over time, which also depends on the type of vaccine administered.

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Overcoming Health Inequities: Spatial Analysis of Seroprevalence and Vaccination Against COVID-19 in Chile

2024 , Muriel Ramírez-Santana , Juan Correa , Loreto Núñez Franz , APABLAZA SALINAS, MAURICIO IVÁN , RUBILAR RAMIREZ, PAOLA ANDREA , VIAL COX, MARIA CECILIA , CORTES SALINAS, LINA JIMENA , HORMAZABAL CASTILLO, JUAN PATRICIO , Luis Canales , VIAL CLARO, PABLO AGUSTIN , AGUILERA SANHUEZA, XIMENA PAZ

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Seroprevalence, spatial distribution, and social determinants of SARS-CoV-2 in three urban centers of Chile

2022 , VIAL CLARO, PABLO AGUSTIN , GONZALEZ WIEDMAIER, CLAUDIA MARTA , Gloria Icaza , Muriel Ramirez-Santana , Rubén Quezada-Gaete , Loreto Núñez-Franz , VIAL COX, MARIA CECILIA , APABLAZA SALINAS, MAURICIO IVÁN , RUBILAR RAMIREZ, PAOLA , Juan Correa , PEREZ ACUÑA, CLAUDIA VERONICA , Andrei Florea , Eugenio Guzmán , María-Estela Lavín , Paula Concha , Manuel Nájera , AGUILERA SANHUEZA, XIMENA PAZ

Abstract Background Seroprevalence studies provide an accurate measure of SARS-CoV-2 spread and the presence of asymptomatic cases. They also provide information on the uneven impact of the pandemic, pointing out vulnerable groups to prioritize which is particularly relevant in unequal societies. However, due to their high cost, they provide limited evidence of spatial spread of the pandemic specially in unequal societies. Our objective was to estimate the prevalence of SARS-CoV-2 antibodies in Chile and model its spatial risk distribution. Methods During Oct–Nov 2020, we conducted a population-based serosurvey in Santiago, Talca, and Coquimbo–La Serena (2493 individuals). We explored the individual association between positive results and socio-economic and health-related variables by logistic regression for complex surveys. Then, using an Empirical Bayesian Kriging model, we estimated the infection risk spatial distribution using individual and census information, and compared these results with official records. Results Seroprevalence was 10.4% (95% CI 7.8–13.7%), ranging from 2% (Talca) to 11% (Santiago), almost three times the number officially reported. Approximately 36% of these were asymptomatic, reaching 82% below 15 years old. Seroprevalence was associated with the city of residence, previous COVID-19 diagnosis, contact with confirmed cases (especially at household), and foreign nationality. The spatial model accurately interpolated the distribution of disease risk within the cities finding significant differences in the predicted probabilities of SARS-CoV-2 infection by census zone (IQR 2.5–15.0%), related to population density and education. Conclusions Our results underscore the transmission heterogeneity of SARS-CoV-2 within and across three urban centers of Chile. Socio-economic factors and the outcomes of this seroprevalence study enable us to identify priority areas for intervention. Our methodological approach and results can help guide the design of interdisciplinary strategies for urban contexts, not only for SARS-CoV-2 but also for other communicable diseases.

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Immunization and SARS-CoV-2 Antibody Seroprevalence in a Country with High Vaccination Coverage: Lessons from Chile

2022 , AGUILERA SANHUEZA, XIMENA PAZ , Gloria Icaza , GONZALEZ WIEDMAIER, CLAUDIA MARTA , RUBILAR RAMIREZ, PAOLA , APABLAZA SALINAS, MAURICIO IVÁN , Muriel Ramírez-Santana , PEREZ ACUÑA, CLAUDIA VERONICA , CORTES SALINAS, LINA JIMENA , Loreto Núñez-Franz , Rubén Quezada-Gaete , CASTILLO LABORDE, CARLA CECILIA , Juan Correa , Macarena Said , HORMAZABAL CASTILLO, JUAN PATRICIO , VIAL COX, MARIA CECILIA , VIAL CLARO, PABLO AGUSTIN

Chile is among the most successful nations worldwide in terms of its COVID-19 vaccine rollout. By 31 December 2021, 84.1% of the population was fully vaccinated, and 56.1% received booster doses using different COVID-19 vaccines. In this context, we aimed to estimate the prevalence of anti-SARS-CoV-2 antibodies following the infection and vaccination campaign. Using a three-stage stratified sampling, we performed a population-based cross-sectional serosurvey based on a representative sample of three Chilean cities. Selected participants were blood-sampled on-site and answered a short COVID-19 and vaccination history questionnaire using Wantai SARS-CoV-2 Ab ELISA to determine seroprevalence. We recruited 2198 individuals aged 7–93 between 5 October and 25 November 2021; 2132 individuals received COVID-19 vaccinations (97%), 67 (3.1%) received one dose, 2065 (93.9%) received two doses, and 936 received the booster jab (42.6%). Antibody seroprevalence reached 97.3%, ranging from 40.9% among those not vaccinated to 99.8% in those with booster doses (OR = 674.6, 154.8–2938.5). SARS-CoV-2 antibodies were associated with vaccination, previous COVID-19 diagnosis, age group, and city of residence. In contrast, we found no significant differences in the type of vaccine used, education, nationality, or type of health insurance. We found a seroprevalence close to 100%, primarily due to the successful vaccination program, which strongly emphasizes universal access.

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Seroprevalence and estimation of the impact of SARS-CoV-2 infection in older adults residing in Long-term Care Facilities in Chile

2022 , RUBILAR RAMIREZ, PAOLA , Jorge Browne , MATUTE WILLEMSEM, MARIA ISABEL , HIRMAS ADAUY, MACARENA SOLEDAD , Cedric Little , Gonzalo Ruz , Carlos Ávila , Tania Gutknecht Mackenzie , AGUILERA SANHUEZA, XIMENA PAZ , VIAL CLARO, PABLO AGUSTIN

Introducción Las personas mayores tienen más riesgo de enfermar gravemente y fallecer por COVID-19. Esta vulnerabilidad aumenta en quienes viven en establecimientos de larga estadía, debido a hacinamiento, mayor dependencia física y contacto con los trabajadores. La evidencia sobre el impacto de la pandemia de estos establecimientos en países de medianos y bajos ingresos ha sido escasa. El objetivo es determinar la seroprevalencia de la infección por SARS-CoV-2 en personas mayores que residen en establecimientos de larga estadía. Así como estimar el impacto global de la infección después de la primera ola de la pandemia. Métodos Diseño transversal con 2099 residentes en tres regiones de Chile, realizado entre septiembre y noviembre 2020. Anticuerpos fueron medidos con test rápido contra SARS-CoV-2. Se estimó el impacto de la infección con los residentes seropositivos, los residentes con antecedentes de reacción en cadena de la polimerasa de transcripción inversa positiva, y residentes que murieron por COVID-19. Análisis bivariado entre el resultado serológico y región, sexo, edad, antecedentes de COVID-19 y dependencia física fueron realizados. Además, realizamos un análisis de correlación entre la seroprevalencia de los centros por municipio y la tasa acumulada de casos confirmados. Resultados La seroprevalencia de anticuerpos en las tres regiones fue 14,7% (intervalo de confianza del 95%: 13,2 a 16,3%). El impacto real de la infección se estimó en 46,4% y la tasa de letalidad en 19,6%. La seroprevalencia de los residentes de los centros por comuna se correlacionó positiva y significativamente con la frecuencia de la enfermedad a nivel comunal. Conclusiones Seroprevalencia superior a la de la población general, observándose un alto impacto de la infección por COVID-19 al final de la primera ola de la pandemia. El lugar en el que se encuentran los establecimientos está directamente relacionado con la tasa de seroprevalencia en ellos. Sistemas de vigilancia epidemiológica deben aplicarse con prontitud para establecer medidas de prevención y control.

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Factors influencing neutralizing antibody response to the original SARS-CoV-2 virus and the Omicron variant in a high vaccination coverage country, a population-based study

2023 , HORMAZABAL CASTILLO, JUAN PATRICIO , Loreto Nuñez-Franz , RUBILAR RAMIREZ, PAOLA ANDREA , APABLAZA SALINAS, MAURICIO IVÁN , VIAL COX, MARIA CECILIA , CORTES SALINAS, LINA JIMENA , Macarena Said , Kathya Olivares , VIAL CLARO, PABLO AGUSTIN , Muriel Ramírez-Santana , GONZALEZ WIEDMAIER, CLAUDIA MARTA , Natalia González , AGUILERA SANHUEZA, XIMENA PAZ

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Attention deficit hyperactivity disorder and its association with heavy metals in children from northern Chile

2020 , María Pía Muñoz , RUBILAR RAMIREZ, PAOLA , Macarena Valdés , María Teresa Muñoz-Quezada , Andrea Gómez , Marta Saavedra , Verónica Iglesias

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