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Browsing by Author "Abarca, Katia"

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A Booster Dose of CoronaVac Increases Neutralizing Antibodies and T Cells that Recognize Delta and Omicron Variants of Concern
(2022) Schultz, Barbara M.; Melo-Gonzalez, Felipe; Duarte, Luisa F.; Galvez, Nicolas M. S.; Pacheco, Gaspar A.; Soto, Jorge A.; Berrios-Rojas, Roslye, V; Gonzalez, Liliana A.; Moreno-Tapia, Daniela; Rivera-Perez, Daniela; Rios, Mariana; Vazquez, Yaneisi; Hoppe-Elsholz, Guillermo; Andrade-Parra, Catalina A.; Vallejos, Omar P.; Pina-Iturbe, Alejandro; Iturriaga, Carolina; Urzua, Marcela; Navarrete, Maria S.; Rojas, Alvaro; Fasce, Rodrigo; Fernandez, Jorge; Mora, Judith; Ramirez, Eugenio; Gaete-Argel, Aracelly; Acevedo, Monica; Valiente-Echeverria, Fernando; Soto-Rifo, Ricardo; Weiskopf, Daniela; Grifoni, Alba; Sette, Alessandro; Zeng, Gang; Meng, Weining; Gonzalez-Aramundiz, Jose, V; Gonzalez, Pablo A.; Abarca, Katia; Kalergis, Alexis M.; Bueno, Susan M.
CoronaVac is an inactivated SARS-CoV-2 vaccine approved by the World Health Organization (WHO). Previous studies reported increased levels of neutralizing antibodies and specific T cells 2 and 4 weeks after two doses of CoronaVac; these levels were significantly reduced at 6 to 8 months after the two doses. Here, we report the effect of a booster dose of CoronaVac on the anti-SARS-CoV-2 immune response generated against the variants of concern (VOCs), Delta and Omicron, in adults participating in a phase III clinical trial in Chile. Volunteers immunized with two doses of CoronaVac in a 4-week interval received a booster dose of the same vaccine between 24 and 30 weeks after the second dose. Neutralization capacities and T cell activation against VOCs Delta and Omicron were assessed 4 weeks after the booster dose. We observed a significant increase in neutralizing antibodies 4 weeks after the booster dose. We also observed a rise in anti-SARS-CoV-2-specific CD4(+) T cells over time, and these cells reached a peak 4 weeks after the booster dose. Furthermore, neutralizing antibodies and SARS-CoV-2-specific T cells induced by the booster showed activity against VOCs Delta and Omicron. Our results show that a booster dose of CoronaVac increases adults' humoral and cellular anti-SARS-CoV-2 immune responses. In addition, immunity induced by a booster dose of CoronaVac is active against VOCs, suggesting adequate protection. IMPORTANCE CoronaVac is an inactivated vaccine against SARS-CoV-2 that has been approved by WHO for emergency use. Phase III clinical trials are in progress in several countries, including China, Brazil, Turkey, and Chile, and have shown safety and immunogenicity after two doses of the vaccine. This report characterizes immune responses induced by two doses of CoronaVac followed by a booster dose 5 months after the second dose in healthy Chilean adults. The data reported here show that a booster dose increased the immune responses against SARS-CoV-2, enhancing levels of neutralizing antibodies against the ancestral strain and VOCs. Similarly, anti-SARS-CoV-2 CD4(+) T cell responses were increased following the booster dose. In contrast, levels of gamma interferon secretion and T cell activation against the VOCs Delta and Omicron were not significantly different from those for the ancestral strain. Therefore, a third dose of CoronaVac in a homologous vaccination schedule improves its immunogenicity in healthy volunteers.
A Third Amblyomma Species and the First Tick-Borne Rickettsia in Chile
(OXFORD UNIV PRESS INC, 2012) Abarca, Katia; Lopez, Javier; Acosta Jamett, Gerardo; Lepe, Paulina; Soares, Joao Fabio; Labruna, Marcelo B.
During November 2010, three ticks were collected from three dogs living in the rural area of Arica, northern Chile. Morphological analyses of the ticks in the laboratory revealed that they were most similar to Amblyomma maculatum Koch and Amblyomma triste Koch. However, because of unique metatarsal spurs, neither of the Chilean specimens could be assigned with certainty to A. maculatum or A. triste, based on external morphology. The mitochondrial 16S rRNA gene partial sequences obtained from two Chilean specimens were 99.5% identical to A. triste from Uruguay, and 99.0% identical to A. maculatum from the United States. Through phylogenetic analysis inferred from partial 16S rRNA sequences, the Chilean specimens were classified as A. triste. Molecular analyses also showed that one of the three Chilean ticks was infected by Candidatus 'Rickettsia andeanae'. These findings extend the geographical distribution of A. triste to Chile, where no tick-associated rickettsia had been reported previously.
Anaplasma platys in dogs, Chile
(CENTER DISEASE CONTROL, 2007) Abarca, Katia; Lopez, Javier; Perret, Cecilia; Guerrero, Javier; Godoy, Paula; Veloz, Ana; Valiente Echeverria, Fernando; Leon, Ursula; Gutjahr, Constanza; Azocar, Teresa
We conducted a 16S rRNA nested PCR for the genus Ehrlichia and Ehrlichia spp. with blood samples from 30 ill dogs in Chile. Phylogenetic analysis was performed by using groESL gene amplification. We identified Anaplasma platys as 1 of the etiologic agents of canine ehrlichiosis.
Asthma and the Risk of Invasive Pneumococcal Disease: A Meta-analysis
(2020) Castro Rodríguez, Jose; Abarca, Katia; Forno, Erick
Invasive pneumococcal disease (IPD) and pneumonia are a leading cause of morbidity and mortality throughout the world, and asthma is the most common chronic disease of childhood. To evaluate the risk of IPD or pneumonia among children with asthma after the introduction of pneumococcal conjugate vaccines (PCVs). Four electronic databases were searched. We selected all cohorts or case-control studies of IPD and pneumonia in populations who already received PCV (largely 7-valent pneumococcal conjugate vaccine), but not 23-valent pneumococcal polysaccharide, in which authors reported data for children with asthma and in which healthy controls were included, without language restriction. Two reviewers independently reviewed all studies. Primary outcomes were occurrence of IPD and pneumonia. Secondary outcomes included mortality, hospital admissions, hospital length of stay, ICU admission, respiratory support, costs, and additional medication use. Five studies met inclusion criteria; of those, 3 retrospective cohorts (∼26 million person-years) and 1 case-control study (N = 3294 children) qualified for the meta-analysis. Children with asthma had 90% higher odds of IPD than healthy controls (odds ratio = 1.90; 95% confidence interval = 1.63-2.11; I2 = 1.7%). Pneumonia was also more frequent among children with asthma than among controls, and 1 study reported that pneumonia-associated costs increased by asthma severity. None of the identified studies had information of asthma therapy or compliance. Despite PCV vaccination, children with asthma continue to have a higher risk of IPD than children without asthma. Further research is needed to assess the need for supplemental 23-valent pneumococcal polysaccharide vaccination in children with asthma, regardless of their use of oral steroids.
Characterization of the humoral and cellular immunity induced by a recombinant BCG vaccine for the respiratory syncytial virus in healthy adults
(2023) Pacheco, Gaspar A.; Andrade, Catalina A.; Galvez, Nicolas M. S.; Vazquez, Yaneisi; Rodriguez-Guilarte, Linmar; Abarca, Katia; Gonzalez, Pablo A.; Bueno, Susan M.; Kalergis, Alexis M.
IntroductionThe human respiratory syncytial virus (hRSV) is responsible for most respiratory tract infections in infants. Even though currently there are no approved hRSV vaccines for newborns or infants, several candidates are being developed. rBCG-N-hRSV is a vaccine candidate previously shown to be safe in a phase I clinical trial in adults (clinicaltrials.gov identifier #NCT03213405). Here, secondary immunogenicity analyses were performed on these samples. MethodsPBMCs isolated from immunized volunteers were stimulated with hRSV or mycobacterial antigens to evaluate cytokines and cytotoxic T cell-derived molecules and the expansion of memory T cell subsets. Complement C1q binding and IgG subclass composition of serum antibodies were assessed. ResultsCompared to levels detected prior to vaccination, perforin-, granzyme B-, and IFN-& gamma;-producing PBMCs responding to stimulus increased after immunization, along with their effector memory response. N-hRSV- and mycobacterial-specific antibodies from rBCG-N-hRSV-immunized subjects bound C1q. ConclusionImmunization with rBCG-N-hRSV induces cellular and humoral immune responses, supporting that rBCG-N-hRSV is immunogenic and safe in healthy individuals.
Chigger Mites (Acariformes: Trombiculidae) of Chiloe Island, Chile, With Descriptions of Two New Species and New Data on the Genus Herpetacarus
(2021) Carolina Silva-de La Fuente, Maria; Stekolnikov, Alexandr A.; Weitzel, Thomas; Beltrami, Esperanza; Martinez-Valdebenito, Constanza; Abarca, Katia; Acosta-Jamett, Gerardo
Three species of chigger mites are recorded in our collections from four species of cricetid rodents on Chiloe Island (southern Chile, Los Lagos Region), an area endemic to scrub typhus (Orientia sp.). Two species are described as new-Herpetacarus (Abonnencia) eloisae sp. nov. and Quadraseta chiloensis sp. nov. One species, Paratrombicula goffi Stekolnikov and Gonzalez-Acuna 2012, is for the first time recorded on a mammal host (one species of cricetid rodent), and its distribution is extended to the Los Lagos Region of Chile. The genus Proschoengastia Vercammen-Grandjean, 1967 is synonymized with the subgenus Herpetacarus (Abonnencia) Vercammen-Grandjean, 1960, and four new combinations are established: Herpetacarus (Abonnencia) herniosa (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) insolita (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) macrochaeta (Brennan and Jones, 1961), comb. nov., and Herpetacarus (Abonnencia) antarctica (Stekolnikov and Gonzalez-Acuna, 2015), comb. nov.
Clinic and epidemiologic description of Clostridium difficile infection in a pediatric population
(SOC CHILENA INFECTOLOGIA, 2015) Maccioni, Andrea; Cerda, Jaime; Terrazas, Claudia; Abarca, Katia
Background: Clostridium difficile (CD)-associated disease (CDAD) and the role of the hypervirulent strain NAP1 have not been well characterized in Pediatrics. Aims: To describe clinical features of CDAD, and to estimate NAP1 frequency and association with disease severity in Pediatrics. Methods: Descriptive, transversal surveillance of diarrheal episodes in Chilean children, hospitalized between February 2012 and December 2013, positive for CD by molecular diagnosis. Results: A total of 66 episodes of diarrhea with identification of CD occurred thougout the study period in children between 1 month and 19 years of age of which 39% were younger than one year old. CD acquisition was predominantly nosocomial and the most common risk factors were: presence of comorbidities (98.6%), use of antibiotics (93.9%), proton pump inhibitors (84.8%), invasive mechanic ventilation (54.5%), feeding tube (48.5%) and immunosuppression (40.9%). Clinical course was mostly mild, but 12 cases presented an unfavorable course, of which 3/26 occurred in children less than one year. Only one case was positive for NAP1 and had a mild course. Conclusion: Diarrhea with identification of CD was present throughout all pediatric ages, including children less than one year old. Analytical and longitudinal studies are required to better characterize the pathogenic role of CD in this age group. CDAD occurred mostly in patients with risk factors, and the clinical course was predominantly mild.
Clinical and serological profile of asymptomatic and non- severe symptomatic COVID-19 cases: Lessons from a longitudinal study in primary care in Latin America
(2021) Puschel, Klaus; Ferreccio, Catterina; Penaloza, Blanca; Abarca, Katia; Rojas, Maria-Paulina; Tellez, Alvaro; Moore, Philippa; Maria Cea, Ana; Wilson, Carlos; Cid, Vicente; Montero, Joaquin
Background: Chile has one of the highest incidences of COVID-19 infection in the world. Primary care can play a key role in early detection and containment of the disease. There is a lack of information on the clinical profile of patients with suspected COVID-19 in primary care, and controversy on the effectiveness of rapid serologic tests in the diagnosis and surveillance of the disease. Aim: To assess the effectiveness of rapid serologic testing in detection and surveillance of COVID-19 cases in primary care. Design & setting: A longitudinal study was undertaken, which was based on a non-random sample of 522 participants, including 304 symptomatic patients and 218 high -risk asymptomatic individuals. They were receiving care at four primary health clinics in an underserved area in Santiago, Chile. Method: The participants were systematically assessed and tested for COVID-19 with transcriptase- polymerase chain reaction (RT-PCR) and serology at baseline, and were followed clinically and serologically for 3 weeks. Results: The prevalence rate of RT-PCR confirmed COVID-19 cases were 3.5 times higher in symptomatic patients (27.5%; 95% confidence interval [CI] = 22.1 to 32.8) compared with asymptomatic participants (7.9%; 95% CI = 4.3 to 11.6). Similarly, the immune response was significantly different between groups. Sensitivity of serologic testing was 57.8% (95% CI = 44.8 to 70.1) during the third week follow- up and specificity was 98.4% (95% CI = 95.5 to 99.7). Conclusion: Rapid serologic testing is ineffective for detecting asymptomatic or non- severe cases COVID-19 at early stages of the disease, but can be of value for surveillance of immunity response in primary care. The clinical profile and immune response of patients with COVID-19 in primary differs from those in hospital- based populations.
Detection of Rickettsia andeanae in two regions of Chile
(SOC CHILENA INFECTOLOGIA, 2013) Abarca, Katia; Lopez, Javier; Acosta Jamett, Gerardo; Martinez Valdebenito, Constanza
Introduction: Candidatus 'Rickettsia andeanae' is recently recognized specie, with no attributed pathogenic role so far. It has been reported in Amblyomma ticks from Peru, USA and Argentina, and recently in Chile, in one specimen of Amblyomma triste from a rural locality in Arica. Objective: To determine the presence of rickettsial agents in ticks from domestic dogs from two Chilean regions. Methods: A transversal descriptive study in Coquimbo and Araucania regions, Consisted in households sampling in the cities of Coquimbo and Angol and nearby rural localities, in spring-summer 2011-2012. One clog per house was examined and ticks Were collected when present; after taxonomic identification, gltA and ompA genes were amplified and sequenced. Results: 462 dogs were examined, 255 had ticks (55%). In the cities just Rhipicephalus sanguineus was found; in rural localities also Amblyomma tigrinum. Obtained sequences in 12 specimens from A. tigrinum corresponded to Candidatus 'Rickettsia andeanae'. Conclusions: We documented the presence of R. andeanae in two distant Chilean regions, which is added to its recently finding in the Northern extreme of the country. This new rickettsial agent limits to Amblyomma ticks and rural areas, as it was reported in other American countries and corresponds with this tick habitat.
Development of a New Genus-Specific Quantitative Real-Time PCR Assay for the Diagnosis of Scrub Typhus in South America
(2022) Jiang, Ju; Martinez-Valdebenito, Constanza; Weitzel, Thomas; Farris, Christina M.; Acosta-Jamett, Gerardo; Abarca, Katia; Richards, Allen L.
Scrub typhus is a potentially severe rickettsiosis, caused by Orientia tsutsugamushi in the Asia-Pacific region. Recently, however, two distinct pathogens, "Candidatus Orientia chuto" and "Candidatus Orientia chiloensis", have been discovered in the Middle East and South America, respectively. Since the novel pathogens differ significantly from O. tsutsugamushi, many established diagnostic methods are unreliable. This work describes the development and validation of a new quantitative real-time PCR (qPCR) assay (Orien16S) for the detection of all known Orientia species. Based on a 94 bp sequence of the 16S rRNA gene (rrs), Orien16S recognized DNA samples from O. tsutsugamushi (n = 41), Ca. O. chiloensis (n = 5), and Ca. O. chuto (n = 1), but was negative for DNA preparations from closely related rickettsiae and other members of the order Rickettsiales (n = 22) as well as unrelated bacterial species (n = 11). After its implementation in Chile, the assay was verified, correctly identifying all tested eschar and buffy coat samples (n = 28) of clinical suspected cases. Furthermore, Orien16S detected Orientia DNA in trombiculid mites collected in endemic regions in southern Chile. The presented novel qPCR assay provides a useful tool for detecting Orientia and diagnosing scrub typhus from all geographical regions.
Differences in the immune response elicited by two immunization schedules with an inactivated SARS-CoV-2 vaccine in a randomized phase 3 clinical trial
(2022) Galvez, Nicolas M. S.; Pacheco, Gaspar A.; Schultz, Barbara M.; Melo-Gonzalez, Felipe; Soto, Jorge A.; Duarte, Luisa F.; Gonzalez, Liliana A.; Rivera-Perez, Daniela; Rios, Mariana; Berrios, Roslye, V; Vazquez, Yaneisi; Moreno-Tapia, Daniela; Vallejos, Omar P.; Andrade, Catalina A.; Hoppe-Elsholz, Guillermo; Iturriaga, Carolina; Urzua, Marcela; Navarrete, Maria S.; Rojas, Alvaro; Fasce, Rodrigo; Fernandez, Jorge; Mora, Judith; Ramirez, Eugenio; Gaete-Argel, Aracelly; Acevedo, Monica L.; Valiente-Echeverria, Fernando; Soto-Rifo, Ricardo; Weiskopf, Daniela; Grifoni, Alba; Sette, Alessandro; Zeng, Gang; Meng, Weining; Gonzalez-Aramundiz, Jose, V; Johnson, Marina; Goldblatt, David; Gonzalez, Pablo A.; Abarca, Katia; Bueno, Susan M.; Kalergis, Alexis M.
Background: The development of vaccines to control the coronavirus disease 2019 (COVID-19) pandemic progression is a worldwide priority. CoronaVac is an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine approved for emergency use with robust efficacy and immunogenicity data reported in trials in China, Brazil, Indonesia, Turkey, and Chile. Methods: This study is a randomized, multicenter, and controlled phase 3 trial in healthy Chilean adults aged & GE;18 years. Volunteers received two doses of CoronaVac separated by 2 (0-14 schedule) or 4 weeks (0-28 schedule); 2302 volunteers were enrolled, 440 were part of the immunogenicity arm, and blood samples were obtained at different times. Samples from a single center are reported. Humoral immune responses were evaluated by measuring the neutralizing capacities of circulating antibodies. Cellular immune responses were assessed by ELISPOT and flow cytometry. Correlation matrixes were performed to evaluate correlations in the data measured. Results: Both schedules exhibited robust neutralizing capacities with the response induced by the 0-28 schedule being better. No differences were found in the concentration of antibodies against the virus and different variants of concern (VOCs) between schedules. Stimulation of peripheral blood mononuclear cells (PBMCs) with Mega pools of Peptides (MPs) induced the secretion of interferon (IFN)-gamma and the expression of activation induced markers in CD4(+) T cells for both schedules. Correlation matrixes showed strong correlations between neutralizing antibodies and IFN-gamma secretion. Conclusions: Immunization with CoronaVac in Chilean adults promotes robust cellular and humoral immune responses. The 0-28 schedule induced a stronger humoral immune response than the 0-14 schedule.
Eco-epidemiology of rodent-associated trombiculid mites and infection with Orientia spp. in Southern Chile
(2023) Silva de la Fuente, Maria Carolina; Perez, Caricia; Martinez-Valdebenito, Constanza; Perez, Ruth; Vial, Cecilia; Stekolnikov, Alexandr; Abarca, Katia; Weitzel, Thomas; Acosta-Jamett, Gerardo
BackgroundScrub typhus is a potentially severe infection caused by bacteria of the genus Orientia, endemic in Asia-Pacific and recently discovered in southern Chile. The presented study aimed to determine the prevalence and species richness of rodent-associated trombiculid mites and their infection with Orientia spp. in different areas of two regions in southern Chile. Methodology/Principal findingsDuring summer 2020, trombiculid mites were collected from rodents captured in three areas in southern Chile known to be endemic for scrub typhus (Cochamo and Chiloe Island in the Los Lagos Region and Tortel in the Aysen Region). A total of 132 rodents belonging to five species were captured using Sherman-like traps; 89.4% were infested with trombiculids. Mite specimens were morphologically identified and subsequently tested by Orientia-specific qPCR. Six mite species were identified. Among chigger-infested rodents, 33.9% carried Orientia-positive mites; this rate was higher in Tortel (63.8%) than in Cochamo (45.0%) and Chiloe Island (2.0%). The analysis of individual mites (n = 901) revealed that 31.2% of Herpetacarus antarctica samples (n = 202) were positive for Orientia DNA; the prevalence was 7.0% in Paratrombicula neuquenensis (n = 213), 6.9% in Herpetacarus eloisae (n = 144), 3.6% in Argentinacarus expansus (n = 55), and 0% in Paratrombicula goffi (n = 110) and Quadraseta chiloensis (n = 177). The southernmost site (Tortel) showed the highest rates of trombiculid infestation, trombiculid load, and Orientia infection in the captured rodents. Conclusions/SignificanceOur study provides new insights into the trombiculid fauna and prevalence of Orientia in mites collected from wild rodents in southern Chile. Orientia DNA was detected in four of the six mite species. Rates of infestation, mite loads, and Orientia prevalences differed geographically and were highest in the Aysen Region. Our data improve our knowledge on possible vectors of scrub typhus and their distribution in Chile.
Effectiveness of varicella vaccine as post exposure prophylaxis in Chilean children
(SOC CHILENA INFECTOLOGIA, 2012) Pinochet, Constanza; Cerda, Jaime; Hirsch, Tamara; Mieres, Jocelyn; Inostroza, Carolina; Abarca, Katia
Effectiveness of varicella vaccine as post exposure prophylaxis in Chilean children Introduction: Efficacy and effectiveness of varicella vaccine (VV) as post exposure prophylaxis (PEP) strategy have shown discordant results for disease risk reduction, and more consistent results in their ability to attenuate the disease. Aim: To assess the effectiveness of VV as PEP among household contacts. Material and Methods: We followed up 33 children after household exposure to a varicella case, of which 15 received VV as PEP and 18 did not received VV. The presence and severity of the disease were clinically determined. Results: Secondary attack rate was 53% among vaccinated and 89% among non-vaccinated children. Overall effectiveness of VV as PEP was 40% (CI95% 1%-64%). The effectiveness for preventing moderate or severe disease was 63% (CI95% 8%-85%) in the entire group and 77% (CI95% 14%-94%) among children vaccinated during the first 3 days post exposure. Vaccine tolerance was acceptable, with a low number of adverse reactions, all of them mild. Conclusion: The results suggest that VV as PEP is effective among household contacts, especially for reducing the severity of the disease.
Fuente de infección de Bordetella pertussis en lactantes hospitalizados por coqueluche
(SOC MEDICA SANTIAGO, 2011) Perret, Cecilia; Viviani, Tamara; Pena, Anamaria; Abarca, Katia; Ferres, Marcela
Background: Despite pertussis vaccination, very young infants have the highest rates of morbidity and mortality caused by the microorganism. Aim: To determine the source of Pertussis infection in infants aged six months or less in Chile. Material and Methods: Twenty six household contacts of 10 young infants hospitalized with confirmed Pertussis were studied for the presence of Bordetella Pertussis by polymerase chain reaction (PCR). Clinical and demographic data were analyzed. Results: Respiratory symptoms were present in 20 (77%) contacts, being cough the most common. Pertussis cases were identified in every household and in 18 (72%) of the household members. Four members with B.pertussis were asymptomatic. Source of infection was identified in 80% (8/10) of the infant cases with ages ranging from 6 to 62 years. Half of primary cases had positive PR and their cough duration was significantly shorter compared to primary cases with negative PER. Conclusions: B. pertussis transmission to young infants occurred mainly within the household where adults are generally the source of the infection. Risk factors for infant infection are the same as in developed countries. Therefore, the same strategies, such as routine vaccination in adolescents and adults or cocoon strategy, will help to prevent this disease in infants. (Rev Med Chile 2011; 139: 448-454).
Rickettsia felis in Rhipicephalus sanguineus from Two Distant Chilean Cities
(2013) Abarca, Katia; Lopez, Javier; Acosta-Jamett, Gerardo; Martinez-Valdebenito, Constanza
Introduction: Rickettsia felis is an emerging agent considered a human threat; although its natural reservoir and agent of transmission is the cat flea, it has been also found in other vectors. R. felis has been identified in Chile in cat fleas and in one specimen of Rhipicephalus sanguineus collected in the Metropolitan Region. The objective of this study was to detect the presence of Rickettsia spp. in R. sanguineus from dogs of two different and distant geographical areas in Chile.
Identification of trombiculid mites (Acari: Trombiculidae) on rodents from Chiloe Island and molecular evidence of infection with Orientia species
(2020) Acosta-Jamett, Gerardo; Martinez-Valdebenito, Constanza; Beltrami, Esperanza; Carolina Silva-de La Fuente, Maria; Jiang, Ju; Richards, Allen L.; Weitzel, Thomas; Abarca, Katia
Background
Immunogenicity and tolerability of a paediatric presentation of a virosomal hepatitis A vaccine in Chilean children aged 1-16 years
(ELSEVIER SCI LTD, 2011) Abarca, Katia; Ibanez, Isabel; de la Fuente, Pablo; Cerda, Leonardo; Bergeret, Jorge; Froesner, Gert; Ibarra, Humberto
We assessed the immunogenicity of the paediatric dose of Epaxal (R) (0.25 mL) and the degrees of seroprotection achieved with the standard dose (0.5 mL) of Epaxal (R) or a dose of Havrix (R) Junior, in children in an open, randomised, controlled, multi-centre, parallel-group study conducted at 2 Chilean study centres. 360 healthy children and adolescents 12 months to <17 years of age not previously vaccinated against hepatitis A were enrolled. Subjects were randomised 2:2:1 to be vaccinated with either Epaxal (R) 0.25 mL [n = 146], Epaxal (R) 0.5 mL [n = 142] or Havrix (R) Junior In = 72] intramuscularly on Day 1 and after 6 months (26 weeks +/- 14 days). Primary end point was the proportion of subjects seroprotected (anti-HAV antibody concentration >= 10 mIU/mL) in the ATP population at Month 1. All vaccines elicited high seroprotection rates at Month 1: 95.7% with Epaxal (R) 0.25 mL, 99.3% with Epaxal (R) 0.5 mL and 94.0% with Havrix (R) Junior. After the booster vaccination, all subjects demonstrated 100% seroprotection with all vaccines. Antibody concentrations were similarly high in all age groups. The paediatric presentation achieved antibody concentrations similar to those achieved with the 0.5 mL dose across the entire age range, and there were no differences across the range of body weights from 9.0 kg to 82.7 kg. All study vaccines were well tolerated and there were no AEs leading to discontinuation. Thus, the paediatric 0.25 mL dose of Epaxal (R) fulfilled the primary objective of showing non-inferiority to the adult 0.5 mL dose and to Havrix (R) Junior, in terms of seroprotection rates achieved. The results show the paediatric dose of Epaxal (R) to be an attractive option when conducting childhood-vaccination programmes. (C) 2011 Elsevier Ltd. All rights reserved.
Immunogenicity, Safety, and Tolerability of V114, a 15-Valent Pneumococcal Conjugate Vaccine, in Immunocompetent Adults Aged 18-49 Years With or Without Risk Factors for Pneumococcal Disease: A Randomized Phase 3 Trial (PNEU-DAY)
(2022) Hammitt, Laura L.; Quinn, Dean; Janczewska, Ewa; Pasquel, Francisco J.; Tytus, Richard; Reddy, K. Rajender; Abarca, Katia; Khaertynova, Ilsiyar M.; Dagan, Ron; McCauley, Jennifer; Cheon, Kyeongmi; Pedley, Alison; Sterling, Tina; Tamms, Gretchen; Musey, Luwy; Buchwald, Ulrike K.
Background Adults with certain medical and behavioral factors are at increased risk for pneumococcal disease (PD). Sequential vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for at-risk adults in some countries. Methods This phase 3 trial evaluated the safety, tolerability, and immunogenicity of sequential administration of either V114 (a 15-valent PCV containing serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) or PCV13, followed 6 months later by PPSV23, in immunocompetent adults aged 18-49 years with or without predefined risk factors for PD (NCT03547167). Overall, 1515 participants were randomized 3:1 to receive either V114 or PCV13, followed by PPSV23. Results Most common solicited adverse events (AEs) following administration of V114 or PCV13 as well as PPSV23 were injection-site pain and fatigue. The proportion of participants with AEs was comparable in both groups. V114 and PCV13 were immunogenic based on opsonophagocytic activity (OPA) geometric mean titers (GMTs) 30 days postvaccination for all serotypes contained in each respective vaccine. OPA GMTs to the 2 unique serotypes in V114 were robust in the V114 group. PPSV23 was immunogenic for all 15 serotypes contained in V114 in both vaccination groups, including 22F and 33F. Conclusions V114 administered alone or sequentially with PPSV23 is well tolerated and immunogenic for all 15 serotypes, including those not contained in PCV13, in immunocompetent adults aged 18-49 years with or without certain medical or behavioral risk factors for PD.
IRF8 Mutations and Human Dendritic-Cell Immunodeficiency
(MASSACHUSETTS MEDICAL SOC, 2011) Hambleton, Sophie; Salem, Sandra; Bustamante, Jacinta; Bigley, Venetia; Boisson Dupuis, Stephanie; Azevedo, Joana; Fortin, Anny; Haniffa, Muzlifah; Ceron Gutierrez, Lourdes; Bacon, Chris M.; Menon, Geetha; Trouillet, Celine; McDonald, David; Carey, Peter; Ginhoux, Florent; Alsina, Laia; Zumwalt, Timothy J.; Kong, Xiao Fei; Kumararatne, Dinakantha; Butler, Karina; Hubeau, Marjorie; Feinberg, Jacqueline; Al Muhsen, Saleh; Cant, Andrew; Abel, Laurent; Chaussabel, Damien; Doffinger, Rainer; Talesnik, Eduardo; Grumach, Anete; Duarte, Alberto; Abarca, Katia; Moraes Vasconcelos, Dewton; Burk, David; Berghuis, Albert; Geissmann, Frederic; Collin, Matthew; Casanova, Jean Laurent; Gros, Philippe
BACKGROUND
Molecular identification of Ehrlichia canis in a dog from Arica, Chile
(SOC CHILENA INFECTOLOGIA, 2012) Lopez, Javier; Abarca, Katia; Isabel Mundaca, M.; Caballero, Carla; Valiente Echeverria, Fernando
We report a molecular confirmed case of canine ehrlichiosis caused by Ehrlichia canis. A 10-year old female crossbred Siberian from the city of Arica, which was infested by ticks, presented hemorrhagic manifestations (hematomas and snout bleeding) and prostration. Blood cell count revealed thrombocytopenia (30,000 platelets/mm(3)). Immunochromatographic rapid testing for E. canis IgG was positive. Amplification and sequencing of a fragment of the 16S rRNA gen from a blood sample showed 100% homology with E. can is from Peril. This is the first report of E. canis in Chile, an agent with known zoonotic potential.

Browsing by Author "Abarca, Katia"

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