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This is a multicenter cohort study including consecutive, hospitalized patients ≥18 years, with moderate to severe COVID-19, carried out to evaluate the relationship between the timing of convalescent plasma administration and 28-day mortality. Data were prospectively collected between May 14, 2020 and October 31, 2020. Patients were grouped according to the timing of administration of convalescent plasma as 7 days. The main outcome variable was 28-day mortality. Independent predictors of mortality were identified by logistic regression. Of 4719 patients receiving convalescent plasma, 3036 (64.3%) were in the general ward, 1171 (24.8%) in the intensive care unit (ICU), and 512 (10.8%) in the ICU on mechanical ventilation. Convalescent plasma was administered to 3113 (66%) patients within the first 3 days of hospital admission, to 1380 (29.2%) between 3 and 7 days, and to 226 after 7 days; 28-day mortality was, respectively, 18.1%, 30.4% and 38.9% (p

ObjectivesTo estimate the protection against laboratory-confirmed SARS-CoV-2 infection, hospitalisations, and death after homologous or heterologous third-dose (booster) in individuals with primary vaccination schemes with rAd26-rAd5, ChAdOx1nCoV-19, BBIBP-CorV or heterologous combinations, during the period of Omicron BA.1 predominance.DesignRetrospective, test-negative, case-control study, with matched analysis.SettingProvince of Buenos Aires, Argentina, between 12/1/21-4/1/21.Participants422,144 individuals ≥50 years who had received two or three doses of COVID-19 vaccines and were tested for SARS-CoV-2.Main outcome measures: Odds ratios of confirmed SARS-CoV-2 infection, hospitalisations and death after administering different boosters, compared to a two-dose primary scheme.ResultsOf 221,933(52.5%) individuals with a positive test, 190,884(45.2%) had received a two-dose vaccination scheme and 231,260(54.8%) a three-dose scheme. The matched analysis included 127,014 cases and 180,714 controls.The three-dose scheme reduced infections (OR 0.81[0.80-0.83]) but after 60 days protection dropped (OR 1.04[1.01-1.06]). The booster dose decreased the risk of hospitalisations and deaths after 15-59 days (ORs 0.28[0.25-0.32] and 0.25[0.22-0.28] respectively), which persisted after administration for 75[66-89] days.Administration of a homologous booster after a primary scheme with vectored-vaccines provided low protection against infections (OR 0.94[0.92-0.97] and 1.05[1.01-1.09] before and after 60 days). Protection against hospitalisations and death was significant (OR 0.30[0.26-0.35] and 0.29[0.25-0.33] respectively) but decreased after 60 days (OR 0.59[0.47-0.74] and 0.51[0.41- 0.64] respectively).The inoculation of a heterologous booster after a primary course with ChAdOx1 nCoV-19, rAd26-rAd5, BBIBP-CorV, or heterologous schemes, offered some protection against infection (OR 0.70[0.68-0.71]), which decreased after 60 days (OR 1.01[0.98-1.04]). The protective effect against hospitalisations and deaths (OR 0.26[0.22-0.31] and 0.22[0.18-0.25] respectively) was clear and persisted after 60 days (OR 0.43[0.35-0.53] and 0.33[0.26-0.41]).ConclusionsThis study shows that, during Omicron predominance, heterologous boosters provide an enhanced protection and longer effect duration against COVID-19-related hospitalisations and death in individuals older than 50, compared to homologous boosters.

ObjectiveThe aim of this study was to assess the immune response after a third dose of SARS-CoV-2 vaccine in patients with rheumatoid arthritis (RA) with undetectable antibody titers after the primary regimen of 2 doses.MethodsPatients with RA with no seroconversion after 2 doses of SARS-CoV-2 vaccine and who received a third dose of either an mRNA or vector-based vaccine were included. Anti-SARS-CoV-2 IgG antibodies, neutralizing activity, and T cell responses were assessed after the third dose.ResultsA total of 21 nonresponder patients were included. At the time of vaccination, 29% were receiving glucocorticoids and 85% biologic disease-modifying antirheumatic drugs (including 6 taking abatacept [ABA] and 4 taking rituximab [RTX]). The majority (95%) received the BNT162b2 vaccine and only one of them received the ChAdOx1 nCoV-19 vaccine. After the third dose, 91% of the patients presented detectable anti-SARS-CoV-2 IgG and 76% showed neutralizing activity. Compared to other treatments, ABA and RTX were associated with the absence of neutralizing activity in 4 out of 5 (80%) patients and lower titers of neutralizing antibodies (median 3, IQR 0-20 vs 8, IQR 4-128;P= 0.20). Specific T cell response was detected in 41% of all patients after the second dose, increasing to 71% after the third dose. The use of ABA was associated with a lower frequency of T cell response (33% vs 87%,P= 0.03).ConclusionIn this RA cohort, 91% of patients who failed to seroconvert after 2 doses of SARS-CoV-2 vaccine presented detectable anti-SARS-CoV-2 IgG after a third dose. The use of ABA was associated with a lower frequency of specific T cell response.

BACKGROUND: Therapies to interrupt the progression of early coronavirus disease 2019 (Covid-19) remain elusive. Among them, convalescent plasma administered to hospitalized patients has been unsuccessful, perhaps because antibodies should be administered earlier in the course of illness. METHODS We conducted a randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adult patients within 72 hours after the onset of mild Covid-19 symptoms. The primary end point was severe respiratory disease, defined as a respiratory rate of 30 breaths per minute or more, an oxygen saturation of less than 93% while the patient was breathing ambient air, or both. The trial was stopped early at 76% of its projected sample size because cases of Covid-19 in the trial region decreased considerably and steady enrollment of trial patients became virtually impossible. RESULTS A total of 160 patients underwent randomization. In the intention-to-treat population, severe respiratory disease developed in 13 of 80 patients (16%) who received convalescent plasma and 25 of 80 patients (31%) who received placebo (relative risk, 0.52; 95% confidence interval [CI], 0.29 to 0.94; P = 0.03), with a relative risk reduction of 48%. A modified intention-to-treat analysis that excluded 6 patients who had a primary end-point event before infusion of convalescent plasma or placebo showed a larger effect size (relative risk, 0.40; 95% CI, 0.20 to 0.81). No solicited adverse events were observed. CONCLUSIONS Early administration of high-titer convalescent plasma against SARS-CoV-2 to mildly ill infected older adults reduced the progression of Covid-19. (Funded by the Bill and Melinda Gates Foundation and the Fundación INFANT Pandemic Fund; Dirección de Sangre y Medicina Transfusional del Ministerio de Salud number, PAEPCC19, Plataforma de Registro Informatizado de Investigaciones en Salud number, 1421, and ClinicalTrials.gov number, NCT04479163.). Fil: Libster, Romina Paula. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Pérez Marc, Gonzalo. Hospital Militar Central, Buenos Aires; Argentina Fil: Wappner, Diego. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Coviello, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Bianchi, Alejandra. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Braem, Virginia. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Esteban, Ignacio. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Caballero, Mauricio Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Wood, Cristian. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Berrueta, Mabel. Hospital Militar Central; Argentina Fil: Rondan, Aníbal. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Lescano, Gabriela Mariel. Hospital Dr. Carlos Bocalandro; Argentina Fil: Cruz, Pablo. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Ritou, Yvonne. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Fernández Viña, Valeria Silvina. Hospital Simplemente Evita; Argentina Fil: Álvarez Paggi, Damián Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Esperante, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Ferreti, Adrián. Hospital Dr. Carlos Bocalandro; Argentina Fil: Ofman, Gaston. University of Oklahoma; Estados Unidos Fil: Ciganda, Álvaro. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal Especializado de Agudos y Cronicos San Juan de Dios.; Argentina Fil: Rodriguez, Rocío. Hospital Simplemente Evita; Argentina Fil: Lantos, Jorge. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Valentini, Ricardo. No especifíca; Fil: Itcovici, Nicolás. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Hintze, Alejandra. No especifíca; Fil: Oyarvide, M. Laura. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Etchegaray, Candela. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Neira, Alejandra. Instituto de Efectividad Clínica y Sanitaria; Argentina Fil: Name, Ivonne. Instituto de Efectividad Clínica y Sanitaria; Argentina Fil: Alfonso, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Swiss Medical Group; Argentina Fil: López Castelo, Rocío. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; Argentina Fil: Caruso, Gisela. Hospital Militar Central; Argentina Fil: Rapelius, Sofía. Hospital Militar Central; Argentina Fil: Alvez, Fernando. Hospital Militar Central; Argentina Fil: Etchenique, Federico. Hospital Militar Central; Argentina Fil: Dimase, Federico. Hospital Militar Central; Argentina Fil: Alvarez, Darío. Hospital Militar Central; Argentina Fil: Aranda, Sofía S.. Hospital Militar Central; Argentina Fil: Sánchez Yanotti, Clara Inés. Hospital Militar Central; Argentina Fil: De Luca, Julián. Hospital Militar Central; Argentina Fil: Jares Baglivo, Sofía. Hospital Militar Central; Argentina Fil: Laudanno, Sofía. Fundación Hematológica Sarmiento; Argentina Fil: Nowogrodzki, Florencia. Swiss Medical Group; Argentina Fil: Larrea, Ramiro. Hospital Municipal San Isidro; Argentina Fil: Silveyra, María. Hospital Militar Central; Argentina Fil: Leberzstein, Gabriel. No especifíca; Fil: Debonis, Alejandra. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Molinos, Juan. Fundación para la Investigación en Infectología Infantil; Argentina Fil: González, Miguel. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Perez, Eduardo. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Kreplak, Nicolás. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Pastor Argüello, Susana. Fundación para la Investigación en Infectología Infantil; Argentina Fil: Gibbons, Luz. Hospital Municipal de San Isidro; Argentina Fil: Althabe, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; Argentina Fil: Bergel, Eduardo. Sanatorio Sagrado Corazón; Argentina Fil: Polack, Fernando Pedro. Provincia de Buenos Aires. Ministerio de Salud; Argentina

BackgroundAlthough paediatric clinical presentations of COVID-19 are usually less severe than in adults, serious illness and death have occurred. Many countries started the vaccination rollout of children in 2021; still, information about effectiveness in the real-world setting is scarce. The aim of our study was to evaluate vaccine effectiveness (VE) against COVID-19-associated-hospitalisations in the 3-17-year population during the Omicron outbreak.MethodsWe conducted a retrospective cohort study including individuals aged 3-17 registered in the online vaccination system of the Buenos Aires Province, Argentina. mRNA-1273 and BNT162b2 were administered to 12-17-year subjects; and BBIBP-CorV to 3-11- year subjects. Vaccinated group had received a two-dose scheme by 12/1/2021. Unvaccinated group did not receive any COVID-19 vaccine between 12/14/2021-3/9/2022, which was the entire monitoring period. Vaccine effectiveness (VE) against COVID-19-associated hospitalisations was calculated as (1-OR) x100.FindingsBy 12/1/2021, 1,536,435 individuals aged 3-17 who had received zero or two doses of SARS-CoV-2 vaccines were included in this study. Of the latter, 1,440,389 were vaccinated and 96,046 not vaccinated. VE were 78·0% [68·7-84·2], 76·4%[62·9-84·5] and 80·0%[64·3-88·0] for the entire cohort, 3-11 subgroup and 12-17 subgroup, respectively. VE for the entire population was 82·7% during the period of Delta and Omicron overlapping circulation and decreased to 67·7% when Omicron was the only variant present.InterpretationThis report provides evidence of high vaccine protection against associated-hospitalisations in the paediatric population during the Omicron outbreak but suggests a decrease of protection when Omicron became predominant. Application of a booster dose in children aged 3-11 warrants further consideration.Research in contextEvidence before this studyThere is limited evidence on the effectiveness of vaccines in the pediatric population, particularly in children aged 3-11 years after the SARS-CoV-2 B.1.1.529 (Omicron) variant’s emergence.We searched preprint and peer-reviewed published articles in PubMed, medRxiv, and SSRN for observational studies, with no language restrictions, using the term “COVID-19 OR SARS-CoV-2” AND “vaccine effectiveness” OR “vaccine impact” AND “children” OR “pediatric” AND “Omicron” published between December 1, 2021, and April 1, 2022. We found 4 studies that included subjects in the 3-17-year population who received a two-dose-scheme of any of the available vaccines-according to each country’s authorisation. Three studies were from the US; two were test-negative-case-control studies and one was a retrospective non-peer-reviewed cohort study. The reported vaccine effectiveness (VE) for 2-doses of BNT162b2-mRNA (Pfizer-BioNTech) in preventing hospitalisations during Omicron predominance was 48-78%; and it was 40-92% for 5-11 and 12-17-year subgroups, respectively. The fourth was a cohort study still in preprint form conducted in Chile and utilized an inactivated vaccine, CoronaVac (SinoVac), widely used in Latin-America. VE for two doses of CoronaVac in the 3-5-year subgroup against hospitalisations was 64% and 69% against ICU admissions.Added value of this studyUp to date, there are no published studies about the effectiveness of the BBIBP-CorV vaccine against hospitalisation in the pediatric population. Additionally, there are no real-world studies from low and middle-income countries about VE in the 12-17 aged population during the Omicron outbreak.This study shows that VE after 14 days or more from two-dose-scheme was 78·0% [68·7-84·2], 76·4% [62·9-84·5] and 80·0% [64·3-88·0] for the 3-17-year entire group, and for 3-11-year (BBIBP-CorV) and 12-17-year (mRNA vaccines) subgroups, respectively. VE for the 3-17-year entire group was 82·7% during the period of Delta and Omicron overlapping circulation and decreased to 67·7% when Omicron was the only variant present. These effects were consistent across all subgroups.Implications of all the available evidenceOur results provide evidence of high vaccine protection against COVID-19 associated-hospitalisations in the pediatric population during the Omicron outbreak, but suggest a decrease of protection when Omicron became predominant. Application of a booster dose in children aged 3-11 warrants further consideration.

Background A first-dose of various vaccines provides acceptable protection against infections by SARS-CoV-2 and evolution to the most severe forms of COVID-19. The recombinant adenovirus (rAd)-based vaccine, Gam-COVID-Vac (Sputnik V), was proven efficacious but information about effectiveness in the real-world setting is lacking. The aim of our study was to investigate the association between the rollout of the first component (rAd26) of Gam-COVID-Vac and PCR-positive tests, hospitalisations and deaths. Methods We conducted a retrospective cohort study which analyzed individuals aged 60-79 who self-registered in the online vaccination system of the Province of Buenos Aires, Argentina, from December 29, 2020 to March 21, 2021. Exclusion criteria were having a previous positive RT-PCR or antigen tests for SARS-CoV-2, having received other vaccines, or two doses of any vaccine. Proportions of new laboratory-confirmed SARS-CoV-2 infections, hospitalisations and deaths until 83 days of vaccination were compared between vaccinated and unvaccinated subjects. Vaccine effectiveness for the three outcomes was calculated as (1–OR) × 100. Kaplan-Meier cumulative incidence curves were constructed. Findings During the study period 415995 registered subjects received the first component of Gam-COVID-Vac; 40387 belonged to the 60-79 age group, and were compared to 38978 unvaccinated. Vaccine effectiveness for preventing laboratory-confirmed infections was 78•6% [CI95% 74·8 - 81·7]; and for reducing hospitalizations and deaths was, respectively, 87·6% [CI95% 80·3 - 92·2] and 84·8% [CI95% 75·0 - 90·7]. Effectiveness was high across all subgroups. Interpretation Similarly to other vaccines, the administration of one dose of Gam-COVID-Vac was effective for a wide range of COVID-19–related outcomes., Facultad de Ciencias Médicas

Recent studies have shown a temporal increase in the neutralizing antibody potency and breadth to SARS-CoV-2 variants in coronavirus disease 2019 (COVID-19) convalescent individuals. Here, we examined longitudinal antibody responses and viral neutralizing capacity to the B.1 lineage virus (Wuhan related), to variants of concern (VOCs: Alpha, Beta, Gamma, and Delta) and a local variant of interest (VOI: Lambda) in volunteers receiving the Sputnik V vaccine in Argentina. A collection of 472 serum samples obtained between January and September 2021 was used. The analysis indicates that while anti-spike IgG levels significantly wane over time, the neutralizing capacity to the first-wave linages of SARS-CoV-2 and VOC are maintained within four months of vaccination. In addition, an improved antibody cross-neutralizing ability to circulating variants of concern (Beta, Gamma and Delta) was observed over time of vaccination. The viral variants that displayed higher escape to neutralizing antibodies with respect to the original virus (Beta and Gamma variants) were the ones showing the largest increase in susceptibility to neutralization over time after vaccination. Our observations indicate that serum neutralizing antibodies are maintained for at least four month and show a reduction of VOC escape over time of vaccination.

Massive vaccination offers great promise for halting the global COVID-19 pandemic. However, the limited supply and uneven vaccine distribution create an urgent need to optimize vaccination strategies. We evaluate SARS-CoV-2-specific antibody responses after Sputnik V vaccination of healthcare workers in Argentina, measuring IgG anti-spike titers and neutralizing capacity after one and two doses in a cohort of naive or previously infected volunteers. By 21 days after receiving the first dose of the vaccine, 94% of naive participants develop spike-specific IgG antibodies. A single Sputnik V dose elicits higher antibody levels and virus-neutralizing capacity in previously infected individuals than in naive ones receiving the full two-dose schedule. The high seroconversion rate after a single dose in naive participants suggests a benefit of delaying administration of the second dose to increase the number of people vaccinated. The data presented provide information for guiding public health decisions in light of the current global health emergency., Graphical abstract, Rossi et al. provide data on antibody responses to Sputnik V vaccine in naive and previously infected volunteers. This study shows a high seroconversion rate following the first dose in naive individuals. In seropositive participants, a single dose of Sputnik V elicits a fast and robust antibody response without apparent benefit from a second dose.

Background: Convalescent plasma, widely utilized in viral infections that induce neutralizing antibodies, has been proposed for COVID-19, and preliminary evidence shows that it might have beneficial effect. Our objective was to determine the risk factors for 28-days mortality in patients who received convalescent plasma for COVID-19 compared to those who did not, who were admitted to hospitals in Buenos Aires Province, Argentina, throughout the pandemic. Methods: This is a multicenter, retrospective cohort study of 2-month duration beginning on June 1, 2020, including unselected, consecutive adult patients with diagnosed COVID-19, admitted to 215 hospitals with pneumonia. Epidemiological and clinical variables were registered in the Provincial Hospital Bed Management System. Convalescent plasma was supplied as part of a centralized, expanded access program. Results: We analyzed 3,529 patients with pneumonia, predominantly male, aged 62±17, with arterial hypertension and diabetes as main comorbidities; 51.4% were admitted to the ward, 27.1% to the Intensive Care Unit (ICU), and 21.7% to the ICU with mechanical ventilation requirement (ICU-MV). 28-day mortality was 34.9%; and was 26.3%, 30.1% and 61.4% for ward, ICU and ICU-MV patients. Convalescent plasma was administered to 868 patients (24.6%); their 28-day mortality was significantly lower (25.5% vs. 38.0%, p, Facultad de Ciencias Médicas

Introducción. El plan de vacunación de la provincia de Buenos Aires ha priorizado los grupos de mayor riesgo epidemiológico, iniciando el proceso de inmunización sobre el Personal de Salud (PS).El presente trabajo tiene por objetivo evaluar el impacto de la vacunación sobre la evolución media de nuevos casos SARS-Cov-2 en PS comparada con la de la población general. Metodología. La información de los casos confirmados se obtuvo del Sistema Nacional de Vigilancia de la Salud, período abril/2020 a marzo/2021. La cantidad de vacunados utilizó la base del sistema VacunatePBA. Resultados. A partir de septiembre, el número de casos comienza a disminuir más pronunciadamente en PS que en la población general. Esta tendencia se consolida con el comienzo del plan de vacunación. Para febrero de 2021 se han inmunizado con la primera dosis el 42% del PS y con la segunda dosis el 24%. Se observa que, en marzo, mientras la cantidad de casos de la Población General aumenta un 10% respecto a febrero, PS disminuye un 35%. Esto indica un descenso significativamente más pronunciado en PS (p-valor < 0.00001). Discusión. A partir de la introducción de la vacuna contra COVID-19 a finales de diciembre en distintos países, se ha comenzado a reportar una baja de la incidencia de nuevos casos de infección por SARS-CoV-2 en PS, coincidente con los hallazgos del presente estudio. Nuestro estudio aporta los primeros datos del país sobre el impacto de las vacunas COVID-19 en PS.

One of the main problems in controlling COVID-19 epidemic spread is the delay in confirming cases. Having information on changes in the epidemic evolution or outbreaks rise before laboratory-confirmation is crucial in decision making for Public Health policies. We present an algorithm to estimate on-stream the number of COVID-19 cases using the data from telephone calls to a COVID-line. By modelling the calls as background (proportional to population) plus signal (proportional to infected), we fit the calls in Province of Buenos Aires (Argentina) with coefficient of determinationR2> 0.85. This result allows us to estimate the number of cases given the number of calls from a specific district, days before the laboratory results are available. We validate the algorithm with real data. We show how to use the algorithm to track on-stream the epidemic, and present the Early Outbreak Alarm to detect outbreaks in advance of laboratory results. One key point in the developed algorithm is a detailed track of the uncertainties in the estimations, since the alarm uses the significance of the observables as a main indicator to detect an anomaly. We present the details of the explicit example in Villa Azul (Quilmes) where this tool resulted crucial to control an outbreak on time. The presented tools have been designed in urgency with the available data at the time of the development, and therefore have their limitations which we describe and discuss. We consider possible improvements on the tools, many of which are currently under development.

Convalescent plasma administration (CPA) is widely used to treat Covid-19, but its effectiveness remains controversial. Here we report the results of an Expanded Access Program of CPA in the province of Buenos Aires, Argentina. We evaluated the relationship between the timing of CPA and 28-day mortality in 4719 hospitalized patients with COVID-19 pneumonia. Early ([≤]3 days from admission) CPA was associated to decreased mortality in patients in the general ward and in the Intensive Care Unit not requiring mechanical ventilation. This suggests that the favorable effect of CPA might be related both to disease acuity and to the therapeutic window., Facultad de Ciencias Médicas

Objetivo: evaluar la persistencia de los anticuerpos IgG contra SARS-CoV2, en trabajadores de salud del subsector público de la Provincia de Buenos Aires, y correlacionarla con variables demográficas (sexo, edad) y otros indicadores de salud (diagnóstico de COVID-19, comorbilidades y embarazo). Metodología: Estudio descriptivo, observacional, de corte transversal. Al personal de salud con un resultado positivo en una primera muestra (N=388) se les realizó una segunda prueba para evaluar la persistencia de anticuerpos mediante ELISA. Resultados: De las 386 personas evaluadas con resultado concluyente, 296 contaban con un primer resultado positivo entre los 30 y los 90 días anteriores a la segunda prueba, el 90% presentó anticuerpos detectables. En aquellas personas con un resultado positivo hacía más de 90 días (45) se observó una caída significativa en la persistencia del 26,7%. No hubo asociaciones significativas entre las variables demográficas y de salud y el resultado de la segunda prueba. Conclusión: Los anticuerpos se mantienen detectables por al menos 90 días en el 90% de los casos analizados. Resulta fundamental continuar este estudio en el tiempo para contar con un período de tiempo mayor entre pruebas. La información aquí mostrada arroja datos interesantes y prometedores en cuanto a la posible protección de nuevos contagios de COVID-19 en personal con alta exposición de riesgo. Estas evidencias podrían contribuir a la toma de decisiones, tanto a nivel local como regional, para la adecuada planificación de la vacunación, así como también, para el manejo de la pandemia ante una posible segunda ola de casos en América Latina.

BackgroundTherapies to interrupt progression of early COVID-19 remain elusive. Among them, convalescent plasma in hospitalized patients was unsuccessful, perhaps because antibody should be administered earlier. We advanced plasma infusions to the first 72 hours of symptoms to arrest COVID-19 progression.MethodsA randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against SARS-CoV2 in elderly subjects within 72 hours of mild COVID-19 symptoms. The primary endpoint was severe respiratory disease defined as a respiratory rate ≥30 and/or an O2satResults160 patients underwent randomization. In the intention-to-treat analysis (ITT), 13/80(16.2%) patients receiving plasma vs. 25/80(31.2%) receiving placebo experienced severe respiratory disease [RR(95%CI)= 0.52(0.29,0.94); p=0.026)] with an RRR=48%.A modified ITT analysis, excluding six subjects who experienced the primary endpoint before infusion, showed a larger effect size [RR(95%CI) = 0.40(0.20, 0.81), p=0.007]. High- and low-titer donor analyses, based on a median IgG titer=1:3,200, evidenced a dose-dependent response with an RRR=73.3% for recipients of high-titer plasma (p=0.016) and a number needed to treat (NNT)=4.4. All secondary endpoints exhibited trends towards protection. No solicited adverse events were observed.ConclusionsEarly administration of high-titer convalescent plasma against SARS-CoV2 to mildly ill infected seniors reduced COVID-19 progression. This safe, inexpensive, outpatient intervention facilitates access to treatment from industrialized to LMIC, can decompress demands on hospitals, and may contribute to save lives.Funded by The Bill & Melinda Gates Foundation and The Fundación INFANT Pandemic Fund. Registered in the Dirección de Sangre y Medicina Transfusional del Ministerio de Salud (PAEPCC19), Plataforma PRIISA (1421), and clinicaltrials.gov (NCT04479163).All authors have completed the ICMJE uniform disclosure form atwww.icmje.org/coi_disclosure.pdfand declare: no support from any organization for the submitted work; RL, GPM, DW and FPP are investigators in a phase 3 SARS CoV2 trial from Pfizer; no other relationships or activities that could appear to have influenced the submitted work.

Introducción: frente a la identificación de la ocurrencia de un brote de COVID19 en el Barrio de Villa Azul y dadas las características de vulnerabilidad del barrio que dificultarían cumplir con el aislamiento domiciliario y las medidas de prevención se implementó una estrategia de aislamiento comunitario como respuesta sanitaria al brote. Objetivo: describir la estrategia de aislamiento comunitario utilizada en el Barrio de Villa Azul para contener y mitigar un brote de COVID19. Métodos: Se identificaron los límites del barrio y se procedió al cierre del mismo con fuerzas de seguridad. Quedó permitida la circulación por dentro del barrio asumiendo que todos los habitantes eran casos sospechosos de COVID19 o bien eran contactos estrechos de algún caso. En los días subsiguientes se continuó con la búsqueda activa de casos sospechosos de COVID19, se realizaron los hisopados en el barrio y se obtuvieron los resultados a las 24 horas. Todos los días, luego de la recepción de los casos se les informaba el resultado a los casos negativos y se iba a las casas de los casos positivos para notificarlos del resultado y sugerirles el aislamiento fuera del barrio para cortar la cadena de contagios. Resultados: En el barrio Villa Azul entre el 22 de mayo y el 20 de junio se registraron 731 casos sospechosos de los cuales 379 fueron casos confirmados para COVID19 (tasa de positividad acumulada del 52,1%). La primera semana hubo entre 20 y 40 casos confirmados diarios con un índice de positividad entre el 66 y 81% pero con el correr del tiempo como consecuencia de la estrategia descripta fueron bajando el número de casos por día y también la positividad. Se trasladaron 193 traslados de pacientes confirmados para aislarse afuera del barrio. Fallecieron 3 personas, todas con comorbilidades (tasa de letalidad 0,8%). Discusión: La estrategia de aislamiento comunitario resultó efectiva para contener el brote de COVID19 en el Barrio de Villa Azul. La posibilidad de garantizar de forma diaria la búsqueda activa de casos, sumado a la posibilidad de hisoparlos en el barrio y a las 24 horas tener el resultado, sugiriendo luego el traslado fuera del mismo de los confirmados para COVID19 fueron algunas de las claves.

Background Convalescent plasma, widely utilized in viral infections that induce neutralizing antibodies, has been proposed for COVID-19, and preliminary evidence shows that it might have beneficial effect. Our objective was to compare epidemiological characteristics and outcomes between patients who received convalescent plasma for COVID-19 and those who did not, admitted to hospitals in Buenos Aires Province, Argentina, throughout the pandemic. Methods This is a multicenter, retrospective cohort study of 2-month duration beginning on June 1, 2020, including unselected, consecutive adult patients with diagnosed COVID-19, admitted to 215 hospitals with pneumonia. Epidemiological and clinical variables were registered in the Provincial Hospital Bed Management System. Convalescent plasma was supplied as part of a centralized, expanded access program. Results We analyzed 3,529 patients with pneumonia, predominantly male, aged 62±17, with arterial hypertension and diabetes as main comorbidities; 51.4% were admitted to the ward, 27.1% to the Intensive Care Unit (ICU), and 21.7% to the ICU with mechanical ventilation requirement (ICU-MV). 28-day mortality was 34.9%; and was 26.3%, 30.1% and 61.4% for ward, ICU and ICU-MV patients. Convalescent plasma was administered to 868 patients (24.6%); their 28-day mortality was significantly lower (25.5% vs. 38.0%, p Logistic regression analysis identified age, ICU admission with and without MV requirement, diabetes and preexistent cardiovascular disease as independent predictors of 28-day mortality, whereas convalescent plasma administration acted as a protective factor. Conclusions Our study suggests that the administration of convalescent plasma in COVID-19 pneumonia admitted to the hospital might be associated with decreased mortality. Key Points Preliminary evidence showed that convalescent plasma might be beneficial in COVID-19. In a cohort of 3,529 patients with pneumonia due to COVID-19, convalescent plasma was administered to 868 patients, without major adverse effects. Convalescent plasma was independently associated with decreased mortality., Facultad de Ciencias Médicas

Objetivo: Evaluar la prevalencia de anticuerpos para SARS Cov-2 en el Barrio Villa Azul, del partido de Quilmes, junto con otras variables demográficas y de movilidad. Métodos: Estudio descriptivo de corte transversal realizado a través de una muestra probabilística sistemática. El tamaño de la muestra fue de 311 casos y consintieron la aplicación del test 284 casos. Fue aplicada una encuesta al 100% de los casos testeados. La información fue procesada con software SPSS 23 y los análisis consideraron la ponderación de la muestra de acuerdo al diseño equiprobabilístico establecido. Resultados: El 61% eran mujeres. La media de edad era de 40 años, la estructura poblacional era similar a la del universo. La presencia de anticuerpos fue del 14,8% de los casos, la mayoría en mujeres y de 40 años que no salieron a trabajar y no utilizaron transporte público. El ser trabajador de la salud no representó un riesgo acrecentado para el contagio. Se observa que de cada un caso sintomático existirían 1,2 asintomáticos. Conclusiones: Hubo una prevalencia mayor de personas con anticuerpos que en otros estudios, aunque comparando territorios similares la prevalencia de anticuerpos fue menor y esto pude ser una consecuencia de un abordaje territorial oportuno. La seroprevalencia fue predominantemente en mujeres y esto no indicaría mayor contagio en este sexo ya que existe incertidumbre en la relación entre infección y anticuerpos. Se observó que los contagios podrían haber sido dentro del hogar o el entorno comunitario ya que afectó a personas que no salían a trabajar.

One of the main problems in controlling COVID-19 epidemic spread is the delay in confirming cases. Having information on changes in the epidemic evolution or outbreaks rise before lab-confirmation is crucial in decision making for Public Health policies. We present an algorithm to estimate on-stream the number of COVID-19 cases using the data from telephone calls to a COVID-line. By modeling the calls as background (proportional to population) plus signal (proportional to infected), we fit the calls in Province of Buenos Aires (Argentina) with coefficient of determination $R^2 > 0.85$. This result allows us to estimate the number of cases given the number of calls from a specific district, days before the lab results are available. We validate the algorithm with real data. We show how to use the algorithm to track on-stream the epidemic, and present the Early Outbreak Alarm to detect outbreaks in advance to lab results. One key point in the developed algorithm is a detailed track of the uncertainties in the estimations, since the alarm uses the significance of the observables as a main indicator to detect an anomaly. We present the details of the explicit example in Villa Azul (Quilmes) where this tool resulted crucial to control an outbreak on time. The presented tools have been designed in urgency with the available data at the time of the development, and therefore have their limitations which we describe and discuss. We consider possible improvements on the tools, many of which are currently under development., 16 pages, 8 figs. Includes details on the Villa Azul outbreak in Argentina

The febrile cholestatic disease as a presentation of Hodgkin's lymphoma is a very unusual condition. We describe here the case of a patient with prolonged fever of unknown origin and progressive jaundice, in whom the diagnosis was made with the analysis of a liver biopsy, given the absence of lymph node involvement that characterizes this disease. We remark the severe and multisystemic involvement of this rapidly progressive disease.

La ictericia febril colestásica como forma de presentación de los linfomas de Hodgkin es un cuadro muy infrecuente. Describimos aquí un caso de síndrome febril prolongado asociado a ictericia progresiva, en el que el diagnóstico de la enfermedad se realiza a través de la biopsia hepática, dada la ausencia de afectación ganglionar que caracteriza a esta enfermedad. Destacamos asimismo el cuadro clínico avanzado y el compromiso multisistémico de una enfermedad rápidamente evolutiva.