Protection of homologous and heterologous boosters after primary schemes of rAd26-rAd5, ChAdOx1 nCoV-19 and BBIBP-CorV during the omicron outbreak in adults of 50 years and older in Argentina: a test-negative case-control study.

Background: After primary vaccination schemes with rAd26-rAd5 (Sputnik V), ChAdOx1 nCoV-19, BBIBP-CorV or heterologous combinations, the effectiveness of homologous or heterologous boosters (Sputnik V, ChAdOx, Pfizer-BioNTech, Moderna) against SARS-CoV-2 infections, hospitalisations and deaths has been scarcely studied. Methods: Test-negative, case-control study, conducted in Argentina during omicron BA.1 predominance, in adults ≥50 years old tested for SARS-CoV-2 who had received two or three doses of COVID-19 vaccines. Outcomes were COVID-associated infections, hospitalisations and deaths after administering mRNA and vectored boosters, < or ≥60 days from the last dose. Findings: Of 422,124 individuals tested for SARS-CoV-2, 221,993 (52.5%) tested positive; 190,884 (45.2%) and 231,260 (54.8%) had received 2-dose and 3-dose vaccination schemes, respectively. The 3-dose scheme reduced infections, hospitalisations and death (OR 0.81 [0.80-0.83]; 0.28 [0.25-0.32] and 0.25 [0.22-0.28] respectively), but protection dropped after 60 days to 1.04 [1.01-1.06]; 0.52 [0.44-0.61] and 0.38 [0.33-0.45]). Compared with 2-dose-schemes, homologous boosters after primary schemes with vectored-vaccines provided lower protection against infections < and ≥60 days (0.94 [0.92-0.97] and 1.05 [1.01-1.09], respectively) but protected against hospitalisations (0.30 [0.26-0.35]) and deaths (0.29 [0.25-0.33]), decreasing after 60 days (0.59 [0.47-0.74] and 0.51 [0.41-0.64], respectively). Heterologous boosters protected against infections (0.70 [0.68-0.71]) but decreased after 60 days (1.01 [0.98-1.04]) and against hospitalisations and deaths (0.26 [0.22-0.31] and 0.22 [0.18-0.25], respectively), which also decreased after 60 days (0.43 [0.35-0.53] and 0.33 [0.26-0.41], respectively). Heterologous boosters protected against infections when applied <60 days (0.70 [0.68-0.71], p < 0.001), against hospitalisations when applied ≥60 days (0.43 [0.35-0.53], p < 0.01), and against deaths < and ≥60 days (0.22 [0.18-0.25], p < 0.01 and 0.33 [0.26-0.41], p < 0.001). Interpretation: During omicron predominance, heterologous boosters such as viral vectored and mRNA vaccines, following Sputnik V, ChAdOx1, Sinopharm or heterologous primary schemes might provide better protection against death; this effect might last longer in individuals aged ≥50 than homologous boosters. Funding: None.

Utilización precoz de tocilizumab en pacientes internados con COVID-19 grave y crítica: un estudio multicéntrico en la Provincia de Buenos Aires / Early use of tocilizumab in hospitalized patients with severe and critical COVID-19 in the Province of Buenos Aires: a multicentric study

Resumen Introducción: El objetivo principal del estudio fue evaluar la mortalidad en los pacientes con COVID-19 graves y críticos, que recibieron tocilizumab (TCZ) -un antagonista monoclonal del receptor de IL-6- de forma temprana vs. tardía. Métodos: Cohorte retrospectiva multicéntrica de pacientes >18 años internados con COVID-19 desde el 1/7/2021-1/8/2022, con 5-7 puntos de gravedad inicial (GI) según Escala de la OMS. Se consideró adminis tración temprana o tardía a la infusión de TCZ ≤ ó > a 48 h del ingreso. Las variables de resultado fueron mortalidad a 28 días y cambio de la GI. Los factores relacionados con la mortalidad fueron evaluados con regresión de Cox. Resultados: Se incluyeron 266 pacientes, 159(60%) varones; edad 58(± 15); con hipertensión arterial (43%), obesidad (37%) y diabetes (27%);70 presentaban GI = 5 (oxígeno suplementario), 143 GI = 6 (ventilación no inva siva o cánula nasal de alto flujo) y 53 GI = 7 (ventilación mecánica invasiva). La mortalidad a 28 días fue 42%, asociada independientemente a: edad, obesidad, GI, días entre la internación y administración del TCZ, y días entre la fecha de inicio de síntomas y el TCZ. La mortalidad para GI 5, 6 y 7 fue 26%, 39% y 72%, respectivamente; 76% y 62% de los pacientes permanecieron estables o mejoraron la GI a los días 3 y 7 de la infusión de TCZ. La mortalidad a 28 días fue 39% (TCZ temprano) vs. 57% (TCZ tardío); p = 0.02; HR = 0.63[0.41-0.99, p = 0.05]). Discusión: Estos resultados apoyan la administración temprana de TCZ en pacientes con COVID-19 grave y crítica.

Abstract Introduction: Tocilizumab (TCZ), an IL-6 receptor antagonist monoclonal antibody is warranted in severe and critically-ill COVID-19 patients. The objective was to evaluate 28-day mortality of patients with severe or critical COVID-19 treated with early vs delayed TCZ. Methods: Multicenter, retrospective cohort study in cluding patients>18 years hospitalized between 7/1/2021- 8/1/2022 with confirmed COVID-19, with 5, 6 and 7 points of WHO Ordinal Initial Severity Scale [SS]. Early or late administration was considered if TCZ was administered before or after 48 hours from admission. Outcomes were28-day mortality and change of SS. Factors related to 28-day mortality were evaluated with Cox regression. Results: 266 patients were included, 159(60%) male; aged 58(± 15); frequent comorbidities were hypertension (42%), obesity (37%) and diabetes (27%). Seventy patients had a SS = 5 (Supplemental O2), 143 had SS = 6 (NIV/ HFNC), and 53 had SS = 7 (IMV). 28-day mortality was 42%(112/266); predictors were age, obesity, higher SS, days between hospitalization and TCZ administration, and fewer days between symptoms onset and TCZ. Mortality of SS 5, 6 and 7 was 26%, 39% and 72% respectively. Com pared with baseline SS points, 76% and 62% of patients remained stable or improved on days 3 and 7 since TCZ administration. 28-day mortality was lower when TCZ was administered before 48 hours (39% vs 57%; p = 0.02; HR = 0.63;[0.41-0.99, p = 0.05]). Discussion: This study supports the early use of TCZ in patients with severe or critical COVID-19.

[Early use of tocilizumab in hospitalized patients with severe and critical COVID-19 in the Province of Buenos Aires: a multicentric study]. / Utilización precoz de tocilizumab en pacientes internados con COVID-19 grave y crítica: un estudio multicéntrico en la Provincia de Buenos Aires.

INTRODUCTION: Tocilizumab (TCZ), an IL-6 receptor antagonist monoclonal antibody is warranted in severe and critically-ill COVID-19 patients. The objective was to evaluate 28-day mortality of patients with severe or critical COVID-19 treated with early vs delayed TCZ. METHODS: Multicenter, retrospective cohort study including patients >18 years hospitalized between 7/1/2021-8/1/2022 with confirmed COVID-19, with 5, 6 and 7 points of WHO Ordinal Initial Severity Scale [SS]. Early or late administration was considered if TCZ was administered before or after 48 hours from admission. Outcomes were 28-day mortality and change of SS. Factors related to 28-day mortality were evaluated with Cox regression. RESULTS: 266 patients were included, 159(60%) male; aged 58(± 15); frequent comorbidities were hypertension (42%), obesity (37%) and diabetes (27%). Seventy patients had a SS = 5 (Supplemental O2), 143 had SS = 6 (NIV/ HFNC), and 53 had SS = 7 (IMV). 28-day mortality was 42%(112/266); predictors were age, obesity, higher SS, days between hospitalization and TCZ administration, and fewer days between symptoms onset and TCZ. Mortality of SS 5, 6 and 7 was 26%, 39% and 72% respectively. Compared with baseline SS points, 76% and 62% of patients remained stable or improved on days 3 and 7 since TCZ administration. 28-day mortality was lower when TCZ was administered before 48 hours (39% vs 57%; p = 0.02; HR = 0.63;[0.41-0.99, p = 0.05]). DISCUSSION: This study supports the early use of TCZ in patients with severe or critical COVID-19.

Introducción: El objetivo principal del estudio fue evaluar la mortalidad en los pacientes con COVID-19 graves y críticos, que recibieron tocilizumab (TCZ) -un antagonista monoclonal del receptor de IL-6- de forma temprana vs. tardía. Métodos: Cohorte retrospectiva multicéntrica de pacientes > 18 años internados con COVID-19 desde el 1/7/2021-1/8/2022, con 5-7 puntos de gravedad inicial (GI) según Escala de la OMS. Se consideró administración temprana o tardía a la infusión de TCZ = ó > a 48 h del ingreso. Las variables de resultado fueron mortalidad a 28 días y cambio de la GI. Los factores relacionados con la mortalidad fueron evaluados con regresión de Cox. Resultados: Se incluyeron 266 pacientes, 159(60%) varones; edad 58(± 15); con hipertensión arterial (43%), obesidad (37%) y diabetes (27%);70 presentaban GI = 5 (oxígeno suplementario), 143 GI = 6 (ventilación no invasiva o cánula nasal de alto flujo) y 53 GI = 7 (ventilación mecánica invasiva). La mortalidad a 28 días fue 42%, asociada independientemente a: edad, obesidad, GI, días entre la internación y administración del TCZ, y días entre la fecha de inicio de síntomas y el TCZ. La mortalidad para GI 5, 6 y 7 fue 26%, 39% y 72%, respectivamente; 76% y 62% de los pacientes permanecieron estables o mejoraron la GI a los días 3 y 7 de la infusión de TCZ. La mortalidad a 28 días fue 39% (TCZ temprano) vs. 57% (TCZ tardío); p = 0.02; HR = 0.63[0.41-0.99, p = 0.05]). Discusión: Estos resultados apoyan la administración temprana de TCZ en pacientes con COVID-19 grave y crítica.

Immune Response to SARS-CoV-2 Third Vaccine in Patients With Rheumatoid Arthritis Who Had No Seroconversion After Primary 2-Dose Regimen With Inactivated or Vector-Based Vaccines.

OBJECTIVE: The 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. METHODS: Patients 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. RESULTS: A 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). CONCLUSION: In 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.

Immunogenicity and reactogenicity of heterologous immunization against SARS CoV-2 using Sputnik V, ChAdOx1-S, BBIBP-CorV, Ad5-nCoV, and mRNA-1273.

Heterologous vaccination against coronavirus disease 2019 (COVID-19) provides a rational strategy to rapidly increase vaccination coverage in many regions of the world. Although data regarding messenger RNA (mRNA) and ChAdOx1 vaccine combinations are available, there is limited information about the combination of these platforms with other vaccines widely used in developing countries, such as BBIBP-CorV and Sputnik V. Here, we assess the immunogenicity and reactogenicity of 15 vaccine combinations in 1,314 participants. We evaluate immunoglobulin G (IgG) anti-spike response and virus neutralizing titers and observe that a number of heterologous vaccine combinations are equivalent or superior to homologous schemes. For all cohorts in this study, the highest antibody response is induced by mRNA-1273 as the second dose. No serious adverse events are detected in any of the schedules analyzed. Our observations provide rational support for the use of different vaccine combinations to achieve wide vaccine coverage in the shortest possible time.

Effectiveness of BBIBP-CorV, BNT162b2 and mRNA-1273 vaccines against hospitalisations among children and adolescents during the Omicron outbreak in Argentina: A retrospective cohort study.

Background: Although 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. Methods: We 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 and 3/9/2022, which was the entire monitoring period. Vaccine effectiveness (VE) against COVID-19-associated hospitalisations was calculated as (1-OR)x100. Findings: By 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-year (BBIBP-CorV) subgroup and 12-17 (mRNA vaccines) 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. Interpretation: This 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-year warrants further consideration. Funding: None.

Timing of convalescent plasma administration and 28-day mortality in COVID-19 pneumonia.

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 <3 days, between 3 and 7 days, and >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<0.001). In the regression model, convalescent plasma administration within the first 3 days of admission was associated with reduced 28-day mortality, compared with the administration after 7 days (OR 0.40, 95% CI 0.30 to 0.53). Early convalescent plasma administration was associated to a significant decreased mortality in patients in the general ward (OR 0.45, 95% CI 0.29 to 0.69) and in the ICU (OR 0.35, 95% CI 0.19 to 0.64), but not in those requiring mechanical ventilation (OR 0.52, 95% CI 0.27 to 1.01). In conclusion, this study suggests that early administration of convalescent plasma to patients with COVID-19 pneumonia is critical to obtain therapeutic benefit.

Efectos de la pandemia en muertes no COVID-19: Análisis en la provincia de Buenos Aires, Argentina, 2020 / Effects of the pandemic on non-COVID-19 deaths: analysis in the province of Buenos Aires, Argentina, 2020

INTRODUCCIÓN: El impacto de la pandemia por COVID-19 sobre la mortalidad abarca tanto sus efectos directos, las defunciones atribuidas al virus SARS-CoV-2, como indirectos sobre otras causas de muerte. "El objetivo del estudio fue determinar la variación sobre causas de muerte no COVID-19 en la provincia de Buenos Aires durante 2020. MÉTODOS: Se realizó un estudio descriptivo de base poblacional, utilizando fuentes secundarias. Se analizó la variación en la mortalidad por causas específicas codificadas según CIE-10, desagregadas a nivel de capítulo y grupos. Las variaciones entre las causas de muerte observadas y esperadas se compararon mediante el método de P-score respecto al quinquenio inmediato anterior (2015-2019). RESULTADOS: Todos los capítulos CIE-10 estudiados se ubican por debajo del promedio de la serie histórica. La mayor variación se registra en causas externas (-20,0%), enfermedades del sistema respiratorio (-9,1%), tumores (-8,1%), enfermedades nutricionales, endocrinas y metabólicas (-5,7%) y finalmente enfermedades del sistema circulatorio (-2,2%). DISCUSIÓN: Se observó la existencia de un reemplazo variable de otras causas de defunción por muertes COVID-19 durante 2020. El análisis de causas múltiples resultó de utilidad para reestimar, en el caso del grupo de influenza (gripe) y neumonías, la participación global de la COVID-19 en la cadena de eventos que contribuyeron al deceso.

Sobrevida en pacientes internados en unidades de cuidados intensivos por COVID-19 en la provincia de Buenos Aires, Argentina / Survival in patients admitted to intensive care units due to COVID-19 in the province of Buenos Aires, Argentina

INTRODUCCIÓN: Uno de los problemas que ha enfrentado el sistema de salud de los diferentes países debido a la pandemia de COVID-19 es la disponibilidad de servicios y atención médica en unidades de cuidados intensivos (UCI). El objetivo fue evaluar la sobrevida en pacientes internados por COVID-19 en UCI entre enero y abril de 2021 en la provincia de Buenos Aires, Argentina. MÉTODOS: Se consideró a los pacientes que, incluidos en el sistema de vigilancia, tuvieran su correlato de información del porcentaje ocupacional de camas de la UCI desde el sistema general. Con esta información se realizó un análisis de sobrevida, considerando tablas de vida, Kaplan-Meier y regresión de Cox. El evento fue el óbito, el tiempo de seguimiento a 96 días y las fechas de internación, defunción y egreso dentro de la UCI como períodos individuales de cada paciente. La capacidad operativa de las UCI fue medida a través del porcentaje de ocupación de camas al momento del ingreso. RESULTADOS: Las UCI con un porcentaje ocupacional mayor al 80% mostraron pacientes con menor curva de sobrevida que sus pares por debajo de esas cifras al momento de ingresar a la internación. DISCUSIÓN: Las diferencias en promedios de sobrevida son estadísticamente diferentes, y muestran dos curvas distintas de supervivencia en el momento en que la segunda ola de COVID-19 afectaba a la Argentina.

Effects of the pandemic on non-COVID-19 deaths: analysis in the province of Buenos Aires, Argentina, 2020 / Efectos de la pandemia en muertes no covid-19: análisis en la provincia de buenos aires, argentina, 2020

RESUMEN INTRODUCCIÓN El impacto de la pandemia por COVID-19 sobre la mortalidad abarca tanto sus efectos directos, las defunciones atribuidas al virus SARS-CoV-2, como indirectos sobre otras causas de muerte. "El objetivo del estudio fue determinar la variación sobre causas de muerte no COVID-19 en la provincia de Buenos Aires durante 2020 MÉTODOS Se realizó un estudio descriptivo de base poblacional, utilizando fuentes secundarias. Se analizó la variación en la mortalidad por causas específicas codificadas según CIE-10, desagregadas a nivel de capítulo y grupos. Las variaciones entre las causas de muerte observadas y esperadas se compararon mediante el método de P-score respecto al quinquenio inmediato anterior (2015-2019) RESULTADOS Todos los capítulos CIE-10 estudiados se ubican por debajo del promedio de la serie histórica. La mayor variación se registra en causas externas (-20,0%), enfermedades del sistema respiratorio (-9,1%), tumores (-8,1%), enfermedades nutricionales, endocrinas y metabólicas (-5,7%) y finalmente enfermedades del sistema circulatorio (-2,2%) DISCUSIÓN Se observó la existencia de un reemplazo variable de otras causas de defunción por muertes COVID-19 durante 2020. El análisis de causas múltiples resultó de utilidad para reestimar, en el caso del grupo de influenza (gripe) y neumonías, la participación global de la COVID-19 en la cadena de eventos que contribuyeron al deceso.

ABSTRACT INTRODUCTION The impact of the COVID-19 pandemic on mortality encompasses both its direct effects, deaths attributed to the SARS-CoV-2 virus, as well as indirect on other causes of death. The objective of the study was to determine the variation in non- COVID-19 causes of death in the province of Buenos Aires during 2020 METHODS A population-based descriptive study was carried out using secondary sources. Specific causes of death coded according to ICD-10, disaggregated by chapter and group, were analyzed. To determine whether there were variations between the observed and expected causes of death, the values of the study period were compared with the immediately preceding five-year period (2015-2019) using the P-score method RESULTS All the ICD-10 chapters studied are below the average of the historical series. The greatest variation appears in the chapter External Causes (-20.0%), Diseases of the Respiratory System (-9.1%), Neoplasms (-8.1%), Endocrine, Nutritional and Metabolic Diseases (-5.7%) and, finally, Diseases of the Circulatory System (-2.2%) DISCUSSION There is a variable change of other causes of death by COVID-19 deaths during 2020. The analysis of multiple causes was useful to re-estimate, in the case of the group of influenza (flu) and pneumonia, the global participation of COVID-19 in the chain of events that contributed to the death.

Survival in patients admitted to intensive care units due to COVID-19 in the province of Buenos Aires, Argentina / Sobrevida en pacientes internados en unidades de cuidados intensivos por covid-19 en la provincia de buenos aires, argentina

RESUMEN INTRODUCCIÓN Uno de los problemas que ha enfrentado el sistema de salud de los diferentes países debido a la pandemia de COVID-19 es la disponibilidad de servicios y atención médica en unidades de cuidados intensivos (UCI). El objetivo fue evaluar la sobrevida en pacientes internados por COVID-19 en UCI entre enero y abril de 2021 en la provincia de Buenos Aires, Argentina MÉTODOS Se consideró a los pacientes que, incluidos en el sistema de vigilancia, tuvieran su correlato de información del porcentaje ocupacional de camas de la UCI desde el sistema general. Con esta información se realizó un análisis de sobrevida, considerando tablas de vida, Kaplan-Meier y regresión de Cox. El evento fue el óbito, el tiempo de seguimiento a 96 días y las fechas de internación, defunción y egreso dentro de la UCI como períodos individuales de cada paciente. La capacidad operativa de las UCI fue medida a través del porcentaje de ocupación de camas al momento del ingreso RESULTADOS Las UCI con un porcentaje ocupacional mayor al 80% mostraron pacientes con menor curva de sobrevida que sus pares por debajo de esas cifras al momento de ingresar a la internación DISCUSIÓN Las diferencias en promedios de sobrevida son estadísticamente diferentes, y muestran dos curvas distintas de supervivencia en el momento en que la segunda ola de COVID-19 afectaba a la Argentina. ^s+

ABSTRACT INTRODUCTION One of the problems faced by the health system in different countries due to COVID-19 pandemic is the availability of medical care services in intensive care units (ICU). The objective was to evaluate survival in patients hospitalized for COVID-19 in the ICUs during the period January-April 2021 in the province of Buenos Aires METHODS Patients included in the surveillance system who had their correlate of information on percentage of bed occupancy in the ICUs from the general system were considered. With this information, a survival analysis was performed, considering life tables, Kaplan-Meier and Cox regression. The event was death, the 96-day follow-up and the dates of admission, death and discharge within the ICUs as individual periods for each patient. Inpatient capacity of the ICUs was measured through the percentage of bed occupancy at the time of admission RESULTS The ICUs with a bed occupancy greater than 80% showed patients with a lower survival curve than those below that figure at the time of admission DISCUSSION The differences in average survival were statistically significant, and show two different survival curves at the time the second wave of COVID-19 affected the country.

Detección de SARS-CoV-2 en contactos estrechos asintomáticos de casos confirmados por diagnóstico molecular, provincia de Buenos Aires, Argentina / Detection of SARS-CoV-2 in asymptomatic close contacts of cases confirmed by molecular diagnosis, Buenos Aires province, Argentina

Resumen La detección de SARS-CoV-2 y su implicancia en el diagnóstico de COVID-19 han sido muy debatidas en la pandemia. El objetivo de este estudio fue evaluar el costo/beneficio de la detección de SARS-CoV-2 en contactos estrechos asintomáticos (CE) mediante el uso de distintas pruebas de diagnóstico molecular. Se estudiaron 51 CE de personas con diagnóstico de SARS-CoV-2 confirmado por RTqPCR, clasificadas por el umbral de ciclos (Ct) (<20, entre 20 y 30 y >30) en hospitales públicos de la provincia de Buenos Aires. Del total de contactos estudiados el 15,7% resultó confirmado para SARS-CoV-2; no hubo contactos positivos de casos con Ct>30. La cantidad de contactos positivos de casos con Ct<20 fue significativamente mayor que la de casos con Ct>20. Las muestras con Ct<20 se asociaron a una carga viral estimada de entre uno a cuatro órdenes de magnitud de diferencia con los rangos de Ct>20. Un 13,7% de contactos positivos fueron casos con Ct<20. De las muestras positivas confirmadas por PCR, correspondientes a la semana epidemiológica 1 de 2021 (SE1), sólo un 19,35% correspondían a muestras con Ct<20 y un 50,7% con Ct entre 20 y 30. Estos datos muestran un incremento de sólo un 3,7% de casos detectados. El esfuerzo por parte del sistema de salud pública para esta estrategia, con bajo poder predictivo, puede tener un efecto negativo para el cumplimiento del aislamiento de los contactos y podría generar una demora en los resultados de los casos sospechosos, sin aportar significativamente en el control de la pandemia.

Abstract The detection of SARS-CoV-2 and its implication in the diagnosis of COVID-19 have been highly debated in the pandemic. The objective of this study was to evaluate the cost/benefit of detecting SARS-CoV-2 in asymptomatic close contacts (CC) using different molecular diagnostic tests. A total of 51 CC of people with a diagnosis of SARS-CoV-2 confirmed by RTqPCR, classified by the cycle threshold (Ct) (<20, between 20 and 30 and >30), were studied in public hospitals in the Province of Buenos Aires. Of the total contacts studied, 15.7% were confirmed for SARS-CoV-2; there were no positive contacts of cases with Ct>30 positive. The number of positive contacts of cases with Ct<20 was significantly higher than that of cases with Ct>20. Samples with Ct<20 were associated with an estimated viral load of one to four orders of magnitude difference with Ct ranges >20. A total of 13.7% of positive close contacts were from cases with Ct<20. When studying positive samples with confirmed diagnosis by PCR, corresponding to 1 epidemiological week of 2021 (EW1), only 19.35% corresponded to samples with Ct<20 and 50.7% with Ct between 20 and 30. From these data it is shown that with the CC test only 3.7% of the cases were detected. The effort by the public health system for this strategy, with low predictive power, may have a negative effect on the fulfillment of the isolation of contacts and could generate a delay in the results of suspected cases, without contributing significantly to controlling the pandemic.

Resumo A detecção do SARS-CoV-2 e seu envolvimento no diagnóstico da COVID-19 têm sido muito discutidos durante a pandemia. O objetivo desse estudo foi avaliar a relação custo/benefício na detecção de SARSCoV- 2 em casos de contatos próximos assintomático (CP), por meio do uso de diferentes testes de diagnóstico molecular. Foram estudados 51 casos de CP de pessoas com diagnóstico de SARS-CoV-2 confirmado pelo RTqPCR, sendo classificados pelo limiar de ciclos (Ct) (<20, entre 20 e 30 e >30), em hospitais públicos da província de Buenos Aires. Do total de contatos estudados, 15,7% foram confirmados para SARS-CoV-2, não houve contatos positivos de casos com Ct>30. O número de contatos positivos de casos com Ct<20, foi significativamente maior que os casos com Ct>20. As amostras com Ct<20 foram associadas a uma carga viral estimada de uma a quatro ordens de magnitude de diferença com os intervalos de Ct>20. Dos casos positivos, 13,7% foram com Ct<20. Das amostras positivas confirmadas por PCR, correspondentes à semana epidemiológica 1 de 2021 (SE1), apenas 19,35% correspondiam a amostras com Ct>20 e 50,7% com Ct entre 20 e 30. Esses dados mostram incremento de apenas 3,7% de casos detectados. O esforço por parte do sistema de saúde pública para essa estratégia, com baixo poder preditivo, pode ter um efeito negativo no cumprimento do isolamento dos contatos e poderia gerar uma demora nos resultados dos casos suspeitos, sem contribuir significativamente para o controle da pandemia.

Effectiveness of the first component of Gam-COVID-Vac (Sputnik V) on reduction of SARS-CoV-2 confirmed infections, hospitalisations and mortality in patients aged 60-79: a retrospective cohort study in Argentina.

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. FUNDING: This study did not receive any funding.

Sputnik V vaccine elicits seroconversion and neutralizing capacity to SARS-CoV-2 after a single dose.

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.

Estimating COVID-19 cases and outbreaks on-stream through phone calls.

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 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 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.

Risk factors for COVID-19 mortality: The effect of convalescent plasma administration.

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<0.001). No major adverse effects occurred. 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 improved outcomes.

Impact of vaccines against COVID-19 on new SARS-COV2 infections in health care workers of the Province of Buenos Aires / Impacto de vacunación covid-19 en las infecciones por sars-cov-2 en personal de salud de la provincia de buenos aires

RESUMEN INTRODUCCIÓN : La vacunación en la provincia de Buenos Aires inició con personal de salud (PS). El objetivo de este trabajo es evaluar el impacto de la vacunación sobre la evolución de los casos de infección por SARS-CoV-2 en el PS, comparado con la de la población general (PG). MÉTODOS : Estudio obsewacional descriptivo de series temporales de casos confirmados de COVID-19, entre abril de 2020 y marzo de 2021. Se utilizó el sistema de información VacunatePBA y el SNVS. Se tomó el grado de inmunización a 14 días de la aplicación de la vacuna. RESULTADOS : A partir de septiembre de 2020, el número de casos disminuyó en el PS, en comparación con la PG. Para fines de febrero de 2021 estaba inmunizado con primera dosis (PD) el 42% del PS y con segunda dosis (SD) el 24%, mientras que en PG solo estaba inmunizado el 0,06% con PD y nadie SD. En marzo de 2021 mientras la cantidad de casos en PG (con 2% inmunizada) aumentó un 10% con respecto a febrero, en PS disminuyó un 35% (95% de esa población inmunizada). Esto indica una disminución significativa entre los nuevos casos de febrero y de marzo en PS (p <0,00001). DISCUSIÓN : A partir del inicio de la vacunación contra COVID-19 a finales de diciembre 2020, se muestra una disminución de casos nuevos de COVID-19 en PS. Este trabajo describe una disminución relativa de los casos en PS luego de la vacunación en la provincia de Buenos Aires y aporta los primeros datos del país sobre el impacto de las vacunas contra COVID-19.

ABSTRACT INTRODUCTION : The vaccination in the province of Buenos Aires has initiated with the health care workers (HCW). The present work aims to evaluate the impact of vaccination on the evolution of confirmed SARS- CoV2 cases in HCW compared to that of the general population (GP). METHODS : The study design is descriptive observational of series were developed confirmed cases, period April 2020 to March 2021. The Sistema Nacional de Vigilancia en Salud (SNVS), and VacunatePBA were used. The grade immunization was estimated at 14 days from the application of the first dose. RESULTS : As of September, the number of cases begins to decrease more sharply in HCW than in the general population. By February 2021, 42% of the HCW had been immunized with the first dose (FD) and 24% with the second dose (SD), while in GP only 0.06% had been immunized with FD and 0% of SD. In March, while the number of GP cases increased by 10% compared to February (only 2% immunized), HCW decreased by 35% (95% immunized). This indicates a significant decrease between the new cases of February and March in HCW (p-value <0.00001). DISCUSSION: Since the introduction of COVID-19 vaccines at the end of December in different countries, a decrease in new cases of COVID-19 in HCW has begun to be reported. The present work describes a relative decrease in HCW cases in a post-vaccination context in the province of Buenos Aires, providing the first data in the country on the impact of COVID-19 vaccines on HCW.

Impacto de vacunación de COVID-19 en las infecciones por SARS-COV-2 en personal de salud de la provincia de Buenos Aires / Impact of vaccines against COVID-19 on new SARS-COV2 infections in health care workers of the Province of Buenos Aires

INTRODUCCIÓN: La vacunación en la provincia de Buenos Aires inició con personal de salud (PS). El objetivo de este trabajo es evaluar el impacto de la vacunación sobre la evolución de los casos de infección por SARS-CoV-2 en el PS, comparado con la de la población general (PG). MÉTODOS: Estudio observacional descriptivo de series temporales de casos confirmados de COVID-19, entre abril de 2020 y marzo de 2021. Se utilizó el sistema de información VacunatePBA y el SNVS. Se tomó el grado de inmunización a 14 días de la aplicación de la vacuna. RESULTADOS: A partir de septiembre de 2020, el número de casos disminuyó en el PS, en comparación con la PG. Para fines de febrero de 2021 estaba inmunizado con primera dosis (PD) el 42% del PS y con segunda dosis (SD) el 24%, mientras que en PG solo estaba inmunizado el 0,06% con PD y nadie SD. En marzo de 2021 mientras la cantidad de casos en PG (con 2% inmunizada) aumentó un 10% con respecto a febrero, en PS disminuyó un 35% (95% de esa población inmunizada). Esto indica una disminución significativa entre los nuevos casos de febrero y de marzo en PS (p <0,00001). DISCUSIÓN: A partir del inicio de la vacunación contra COVID-19 a finales de diciembre 2020, se muestra una disminución de casos nuevos de COVID-19 en PS. Este trabajo describe una disminución relativa de los casos en PS luego de la vacunación en la provincia de Buenos Aires y aporta los primeros datos del país sobre el impacto de las vacunas contra COVID-19

Exceso de mortalidad por la pandemia de COVID-19 durante 2020 en la provincia de Buenos Aires, Argentina / Excess mortality associated with the COVID-19 pandemic during 2020 in the Buenos Aires province, Argentina

INTRODUCCIÓN: El exceso de mortalidad (EM) provee una métrica robusta del impacto en este indicador durante un evento pandémico o fuera de lo habitual. Se realizó el presente estudio con el objetivo de determinar el impacto de la pandemia por la enfermedad por el nuevo coronavirus (COVID-19) sobre el exceso de muertes ocurrido en la provincia de Buenos Aires (PBA). MÉTODOS: Estudio descriptivo retrospectivo de base poblacional. Para el análisis del EM se utilizó el método P-score, con base en la comparación de la mortalidad entre un período basal -histórico 2015-2019, respecto a las defunciones con ocurrencia en la Provincia durante 2020. RESULTADOS: La PBA tiene un registro provisorio de un EM promedio de 7,59%, considerando como línea de base el límite superior de confianza del 95% de la serie histórica 2015-2019, o del 12,15% si se considera el promedio histórico. Se observa un impacto diferencial del EM según el sexo y el grupo etario. DISCUSIÓN: Las muertes por COVID-19 en la PBA superan el EM, lo que podría indicar la existencia de reemplazo de otras causas de defunción. Este resultado, que distingue a la PBA de los países de América Latina relevados y otros países europeos y de Oceanía, no permitiría estimar un subregistro en la contabilización de defunciones por COVID-19.