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.

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.

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.

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.

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

COVID-19 y vulnerabilidad social Análisis descriptivo de una serie de casos del gran Bueno Aires / COVID-19 and social vulnerability: descriptive study about a case series in Gran Buenos Aires

INTRODUCCIÓN: La morbimortalidad por la enfermedad por el nuevo coronavirus (COVID-19) constituye un problema de salud pública en la Provincia de Buenos Aires y en el resto de Argentina. Las poblaciones con vulnerabilidad social están expuestas a riesgos de manera potenciada. OBJETIVO: Describir la evolución de los casos confirmados de COVID-19 en el Gran Buenos Aires, localizados en zonas con diferentes características sociales categorizadas por vulnerabilidad socioterritorial, desde el inicio de la pandemia hasta el 15 de julio de 2020. MÉTODOS: Estudio descriptivo de corte transversal. Las variables analizadas fueron sexo, edad, evolución de la enfermedad y domicilio categorizado por medio del índice de vulnerabilidad socioterritorial (IVST). RESULTADOS: La mayor cantidad de casos positivos para COVID-19 se encontró en el grupo etario de 20 a 59 años, y el 48% fueron mujeres. El 47% de los casos estudiados residían en zonas vulnerables. El 28% de los casos confirmados requirieron internación. Se internaron en unidades de cuidados intensivos el 3,8% del total de los casos confirmados. Los casos de residentes en zonas no vulnerables tuvieron mayor requerimiento de cuidados intensivos. La letalidad fue de 3,5%, mayor en los varones, y más elevada en residentes de zonas no vulnerables, con una diferencia estadísticamente significativa respecto a los pertenecientes a zonas vulnerables. En la distribución por grupos etarios, se observó un exceso de letalidad estadísticamente significativo en menores de 60 años. DISCUSIÓN: Se observó un número mayor de internaciones en UCI y en la letalidad del grupo de población residente en territorio no vulnerable.

Seroprevalencia de infección por SARS-CoV-2 en personal de salud de la Región Sanitaria VIII, provincia de Buenos Aires, Argentina / Pandemic and social inequiality: the popular neighborhoods of the Buenos Aires suburbs in preventive social isolation

INTRODUCCIÓN en el contexto de pandemia por el nuevo coronavirus (COVID-19), la situación del personal de salud (PS) constituye un foco de interés, tanto por su alta exposición como por la posibilidad de convertirse en diseminadores de la infección en la comunidad. Estos trabajadores enfrentan un riesgo laboral de morbimortalidad sin precedentes. El objetivo fue estimar la seroprevalencia de infección por el nuevo coronavirus (SARS-CoV-2) en el PS de la Región Sanitaria VIII, provincia de Buenos Aires, durante junio de 2020. MÉTODOS se utilizó un diseño transversal. Se realizó un muestreo probabilístico por conglomerados bietápico. Se recabaron datos a partir de un cuestionario autoadministrado y una muestra de sangre para determinación de anticuerpos. Se utilizó el test COVIDAR IgG e IgM®. RESULTADOS se incluyeron 738 trabajadores de la salud, la tasa de respuesta general fue del 73,80 %. El 71,83% fueron mujeres, el 46,39% tenía entre 35 y 49 años. Enfermeros y médicos representaron más de la mitad del personal. El 75,86% refirió usar siempre el equipo de protección personal. El 5,61% tuvo contacto estrecho con un caso confirmado de COVID-19. El 4,60% tenía un hisopado nasofaríngeo previo, con resultado negativo. Se encontraron cinco trabajadores con IgG positiva para SARS-CoV-2 (cuatro mujeres y un varón) e IgM negativa. La edad media de los casos fue de 35 años, dos fueron asintomáticos, en ninguno se había tomado muestra de hisopado. La seroprevalencia general fue de 0,75%, sin diferencias significativas entre estratos. DISCUSIÓN la seroprevalencia hallada fue baja, con una gran proporción de trabajadores susceptibles a la infección. Se refuerza la necesidad de complementar las estrategias de vigilancia epidemiológica pasiva con el monitoreo serológico en personal de salud.

INTRODUCTION in the context of the new coronavirus (COVID-19) pandemic, the situation of health care workers (HCW) constitutes a focus of interest, due to their high exposure and the possibility of becoming disseminators of the infection in the community These workers face an unprecedented occupational risk of morbidity and mortality The aim of this study was to estimate the seroprevalence of the new coronavirus (SARS-CoV-2) infection in health workers of the Sanitary Region VIII, at province of Buenos Aires during June 2020. METHODS a cross-sectional design was used. A probabilistic sampling by two-stage conglomerates was carried out. Data were collected from a self-administered questionnaire and a blood sample for antibody identification. The COVIDAR IgG and IgM® test was used. RESULTS 738 health workers were included; the overall response rate was 73.80%. 71.83% of that were women; 46.39% were between 35 and 49 years of age. Nurses and physicians accounted for more than half of the staff. 75.86% of people claimed to always use personal protective equipment. 5.61% of people had close contact with a confirmed case of COVID-19.4.60% of people had previously had a nasopharyngeal swab with a negative result. Five workers had positive IgG for SARS-CoV-2 (four women and one man), with negative IgM. The mean age of the cases was 35 years old; two of them were asymptomatic; neither of them had a swab sample taken. The overall seroprevalence was 0.75%, with no significant differences between strata. DISCUSSION the seroprevalence found was low; indicating a large proportion of workers was susceptible to infection. We stress the need to complement passive epidemiological surveillance strategies with serological monitoring in health workers.

Seroprevalencia de infección por SARS-COV-2 en personal de salud de la region sanitaria VIII, provincia de Buenos Aires, Argentina / Seroprevalence of the SARS-CoV-2 infection in health workers of the Sanitary Region VIII, at province of Buenos Aires

INTRODUCCIÓN: en el contexto de pandemia por el nuevo coronavirus (COVID-19), la situación del personal de salud (PS) constituye un foco de interés, tanto por su alta exposición como por la posibilidad de convertirse en diseminadores de la infección en la comunidad. Estos trabajadores enfrentan un riesgo laboral de morbimortalidad sin precedentes. El objetivo fue estimar la seroprevalencia de infección por el nuevo coronavirus (SARS-CoV-2) en el PS de la Región Sanitaria VIII, provincia de Buenos Aires, durante junio de 2020. MÉTODOS: se utilizó un diseño transversal. Se realizó un muestreo probabilístico por conglomerados bietápico. Se recabaron datos a partir de un cuestionario autoadministrado y una muestra de sangre para determinación de anticuerpos. Se utilizó el test COVIDAR IgG e IgM®. RESULTADOS: se incluyeron 738 trabajadores de la salud, la tasa de respuesta general fue del 73,80 %. El 71,83% fueron mujeres, el 46,39% tenía entre 35 y 49 años. Enfermeros y médicos representaron más de la mitad del personal. El 75,86% refirió usar siempre el equipo de protección personal. El 5,61% tuvo contacto estrecho con un caso confirmado de COVID-19. El 4,60% tenía un hisopado nasofaríngeo previo, con resultado negativo. Se encontraron cinco trabajadores con IgG positiva para SARS-CoV-2 (cuatro mujeres y un varón) e IgM negativa. La edad media de los casos fue de 35 años, dos fueron asintomáticos, en ninguno se había tomado muestra de hisopado. La seroprevalencia general fue de 0,75%, sin diferencias significativas entre estratos. DISCUSIÓN: la seroprevalencia hallada fue baja, con una gran proporción de trabajadores susceptibles a la infección. Se refuerza la necesidad de complementar las estrategias de vigilancia epidemiológica pasiva con el monitoreo serológico en personal de salud

Incidence of influenza-associated mortality and hospitalizations in Argentina during 2002-2009.

BACKGROUND: We estimated rates of influenza-associated deaths and hospitalizations in Argentina, a country that recommends annual influenza vaccination for persons at high risk of complications from influenza illness. METHODS: We identified hospitalized persons and deaths in persons diagnosed with pneumonia and influenza (P&I, ICD-10 codes J10-J18) and respiratory and circulatory illness (R&C, codes I00-I99 and J00-J99). We defined the influenza season as the months when the proportion of samples that tested positive for influenza exceeded the annual median. We used hospitalizations and deaths during the influenza off-season to estimate, using linear regression, the number of excess deaths that occurred during the influenza season. To explore whether excess mortality varied by sex and whether people were age <65 or ≥ 65 years, we used Poisson regression of the influenza-associated rates. RESULTS: During 2002-2009, 2411 P&I and 8527 R&C mean excess deaths occurred annually from May to October. If all of these excess deaths were associated with influenza, the influenza-associated mortality rate was 6/100,000 person-years (95% CI 4-8/100,000 person-years for P&I and 21/100,000 person-years (95% CI 12-31/100,000 person-years) for R&C. During 2005-2008, we identified an average of 7868 P&I excess hospitalizations and 22,994 R&C hospitalizations per year, resulting in an influenza-associated hospitalization rate of 2/10,000 person-years (95% CI 1-3/10,000 person-years) for P&I and 6/10,000 person-years (95% CI 3-8/10,000 person-years) for R&C. CONCLUSION: Our findings suggest that annual rates of influenza-associated hospitalizations and death in Argentina were substantial and similar to neighboring Brazil.