Person: Vial, Pablo
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Publication Seroprevalence and estimation of the impact of SARS-CoV-2 infection in older adults residing in Long-term Care Facilities in Chile(2022) Rubilar, Paola; Hirmas Adauy, Macarena; Matute, María Isabel; Browne, Jorge; Little, Cedric; Ruz, Gonzalo; Aguilera, Ximena; Avila, Carlos; Vial, Pablo; Gutknecht Mackenzie, TaniaIntroduction Older adults are at a higher risk of severe illness and death from COVID-19. This vulnera bility increases in those who live in long-term care facilities due to overcrowding, greater physical dependence, and contact with health workers. Evidence on the impact of the pan demic on these establishments in low- and middle-income countries has been scant. This study aims to determine the seroprevalence of SARS-CoV-2 in older people residing in long-term care facilities and estimate the impact of infection after the first wave of the pandemic. Methods A cross-sectional design with 2099 residents in three regions of Chile was carried out be tween September and November 2020. Measurement of antibodies was performed with a rapid test. The impact of SARS-CoV-2 infection was estimated with seropositive residents, those who had a history of positive polymerase chain reaction tests, and those who died from COVID-19. Bivariate analysis with the region, sex, age, history of COVID-19, physical dependence, and serological results were performed. In addition, we performed a correla tion analysis between the seroprevalence of the centers by the municipality and the rate of confirmed cases. Results The seroprevalence of SARS-CoV-2 antibodies in the three regions was 14.7% (95% confi dence interval: 13.2 to 16.3%), the infection impact was 46.4%, and the fatality rate was 19.6%. A significant correlation was found between the seroprevalence of older adults re siding in long-term care facilities and the cumulative incidence by municipalities. Conclusions The seroprevalence of older adults residing in long-term care facilities was higher than the general population. The high impact of infection among this population at the end of the first wave of the COVID-19 pandemic is similar to other countries. The centers' environ ment is directly related to COVID-19 infection. Morbidity and mortality monitoring sys tems should be implemented promptly to establish prevention and control measurPublication 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, Juan; Nuñez-Franz, Loreto; Rubilar, Paola; Apablaza, Mauricio; Vial Cox, María Cecilia; Cortes Salinas, Lina Jimena; González, Natalia; Vial, Pablo; Said, Macarena; Gonzalez Wiedmaier, Claudia; Olivares, Kathya; Aguilera, Ximena; Ramírez-Santana, MurielThe study compared immunity to the original SARS-CoV-2 virus (Wuhan) and the Omicron variant using neutralizing antibodies (NAbs), that provide a good approximation of protective immunity. The results might help determine immunization strategies. Design and methods: Unlike previous studies, we analyzed NAbs in a random sample of 110 IgG positive sera from individuals who participated in a population-based seroprevalence transversal study, carried out in May 2022 in two Chilean cities, a country with high vaccination coverage. Results: Our findings indicate that 98.2% of individuals had NAbs against Wuhan, 65.5% against Omicron, and 32.7% tested positive for Wuhan but not Omicron. Factors influencing protective immunity included a prior natural infection and the number of vaccines received. NAbs titers against the original virus were high, demonstrating vaccine effectiveness in the population. However, the level of antibodies decreased when measuring NAbs against Omicron, particularly among older individuals, indicating a decline in vaccine protection. Previous COVID-19 episodes acted as a natural booster, increasing NAbs titers against both virus strains. Conclusions: Protective immunity against the original Wuhan SARS-CoV-2 virus is reduced when compared to Omicron variant. Updating vaccine to target emerging variants and continued monitoring of effectiveness at the population level are necessary.Publication Viral shedding and viraemia of Andes virus during acute hantavirus infection: a prospective study(2024) Ferrés, Marcela; Martínez, Constanza; Henriquez, Carolina; Marco, Claudia; Barrera, Aldo; Palma, Carlos; Barriga, Gonzalo; Cuiza, Analia; Ferreira, Leonila; Rioseco, María; Calvo, Mario; Fritz, Ricardo; Bravo, Sebastián; Bruhn, Alejandro; Graf, Jerónimo; Llancaqueo, Alvaro; Rivera, Gonzalo; Cerda, Carolina; Tischler, Nicole; Valdivieso, Francisca; Vial, Pablo; Mertz, Gregory; Vial Cox, María Cecilia; Le Corre, NicoleBackground: Andes virus (ANDV) is a zoonotic Orthohantavirus leading to hantavirus cardiopulmonary syndrome. Although most transmissions occur through environmental exposure to rodent faeces and urine, rare person-to-person transmission has been documented, mainly for close contacts. This study investigates the presence and infectivity of ANDV in body fluids from confirmed cases and the duration of viraemia. Methods: In this prospective study, 131 participants with confirmed ANDV infection were enrolled in Chile in a prospective study between 2008 and 2022. Clinical samples (buffy coat, plasma, gingival crevicular fluid [GCF], saliva, nasopharyngeal swabs [NPS], and urine) were collected weekly for 3 weeks together with clinical and epidemiological data. Samples were categorised as acute or convalescent (up to and after 16 days following onset of symptoms). Infectivity of positive fluids was assessed after the culture of samples on Vero E6 cells and use of flow cytometry assays to determine the production of ANDV nucleoprotein. Findings: ANDV RNA was detected in 100% of buffy coats during acute phase, declining to 95% by day 17, and to 93% between days 23-29. ANDV RNA in GCF and saliva decreased from 30% and 12%, respectively, during the acute phase, to 12% and 11% during the convalescent phase. Successful infectivity assays of RT-qPCR-positive fluids, including GCF, saliva, NPS, and urine, were observed in 18 (42%) of 43 samples obtained during the acute phase of infection. After re-culture, the capacity to infect Vero E6 cells was maintained in 16 (89%) of 18 samples. Severity was associated with the presence of ANDV RNA in one or more fluids besides blood (odds ratio 2·58 [95% CI 1·42-5·18]). Interpretation: ANDV infection is a systemic and viraemic infection, that affects various organs. The presence of infectious particles in body fluids contributes to our understanding of potential mechanisms for person-to-person transmission, supporting the development of preventive strategies. Detection of ANDV RNA in additional fluids at hospital admission is a predictor of disease severity. Funding: National Institutes of Health and Agencia de Investigación y Desarrollo.Publication Post-COVID-19 condition: a sex-based analysis of clinical and laboratory trends(2024) Delfino, Carlos; Poli Harlowe, María Cecilia; Vial Cox, María Cecilia; Vial, Pablo; Martínez, Gonzalo; Riviotta, Amy; Arbat, Catalina; Mac-Guire, Nicole; Hoppe, Josefina; Carvajal, Cristóbal; Munoz Venturelli, PaulaBackground and aim: Post-COVID-19 condition (PCC) encompasses long-lasting symptoms in individuals with COVID-19 and is estimated to affect between 31-67% of patients, with women being more commonly affected. No definitive biomarkers have emerged in the acute stage that can help predict the onset of PCC, therefore we aimed at describing sex-disaggregated data of PCC patients from a local cohort and explore potential acute predictors of PCC and neurologic PCC. Methods: A local cohort of consecutive patients admitted with COVID-19 diagnosis between June 2020 and July 2021 were registered, and clinical and laboratory data were recorded. Only those <65 years, discharged alive and followed up at 6 and 12 months after admission were considered in these analyses. Multivariable logistic regression analysis was performed to explore variables associated with PCC (STATA v 18.0). Results: From 130 patients in the cohort, 104 were contacted: 30% were women, median age of 42 years. At 6 months, 71 (68%) reported PCC symptoms. Women exhibited a higher prevalence of any PCC symptom (87 vs. 60%, p = 0.007), lower ferritin (p = 0.001) and procalcitonin (p = 0.021) and higher TNF levels (p = 0.042) in the acute phase compared to men. Being women was independently associated to 7.60 (95% CI 1.27-45.18, p = 0.026) higher risk for PCC. Moreover, women had lower return to normal activities 6 and 12 months. Conclusion: Our findings highlight the lasting impact of COVID-19, particularly in young women, emphasising the need for tailored post-COVID care. The lower ferritin levels in women are an intriguing observation, warranting further research. The study argues for comprehensive strategies that address sex-specific challenges in recovery from COVID-19.