Comparison of epidemiological and clinical characteristics of SARS, pandemic (H1N1) 2009 and COVID-19, and consideration on prevention and control strategies of COVID-19 / 中华预防医学杂志

We compared the epidemiological and clinical characteristics of severe acute respiratory syndrome (SARS), pandemic (H1N1) 2009 and COVID-19 and found that COVID-19 was more contagious, more concealed in transmission, with greater infectious intensity and more severe clinical manifestations. If the COVID-19 epidemic is not effectively controlled, it will have a serious impact on human health, and even social development. Recognizing the characteristics of three diseases, especially COVID-19, and improving the disease awareness of COVID-19 will help better implement the guidelines of 'scientific prevention and treatment, precise implementation' and prevent and control COVID-19.

Demographic and Clinical Characteristics of Pandemic Influenza A (H1N1) 2009 Outbreak in Kerala, Southern India.

Aims: To study the clinical and epidemiological features in the affected individuals from different areas of Kerala, India. Study design: Population based cross sectional study. Place and Duration of Study: Regional Facility for Molecular Diagnostics, Rajiv Gandhi Center for Biotechnology and Directorate of Health Services, Kerala, between August 2009 and September 2010. Methodology: We conducted active surveillance for referral hospitals with specialist inpatient care in Kerala during pandemic periods. Oropharyngeal or nasopharyngeal swabs were tested for influenza viruses by Real time reverse transcriptase PCR. Results: A total of 4252 samples were tested for H1N1 influenza virus, of which, 30.17% were positive for pandemic influenza A H1N1 and 10.49% were positive for Influenza A (seasonal flu). Severe disease and mortality in the pandemic influenza A (H1N1) 2009 infection predominantly affected relatively healthy adolescents and adults between the age of 10 and 50 years. Both Males (29.28%) and Females (31.15%) were equally effected even though we observed a significant difference (P=.02). 141 cases exhibited lower respiratory tract symptoms. Pneumonia alone accounted for 28% of complicated cases. It was observed that the majority of cases (29.28%) during the first outbreak season were imported from affected overseas regions. Conclusion: In this study, prevalence of Influenza A H1N1 was high in the healthy younger population and there wasn’t any sex related susceptibility for Influenza infection. Majority of districts showed a positivity of approximately 10-30%, few with high positivity of >30%. Our findings highlight the importance of regular influenza immunization as it is significant to understand that the H1N1 (2009) virus may still circulate for many years with similar high severity.

Oseltamivir-resistant influenza A(H1N1) pdm09 virus: first reported case from India.

Background: Recent studies on antiviral susceptibiliy from South-East Asia, Europe and the United States have shown sporadic neuraminidase inhibitor (NAI) resistance in A(H1N1)pdm09 viruses. We undertook a study to evaluate NAI resistance in these viruses isolated in India. Methods: Pandemic influenza viruses, isolated from 2009 to 2013, along with clincal samples were genetically analysed for known resistance markers in the neuraminidase (NA) gene. Clinical samples (n=1524) were tested for H275Y (N1 numbering; H274Y in N2 numbering) mutation by real time reverse transcriptase PCR (rRT-PCR). One hundred and ten randomly selected resistant and sensitive viruses were analysed by phenotypic assay. Results: All but one of the 2013 A(H1N1)pdm09 isolates were sensitive to oseltamivir. Genetic analysis of this isolate as well as the original clinical material showed that the presence of H275Y mutation was responsible for reduced susceptibility to oseltamivir in the patient. This was confirmed by phenotypic assay. Conclusion: The emergence of a pandemic influenza strain resistant to oseltamivir emphasizes the need for monitoring antiviral resistance as part of the National Influenza Programme in India.

Pandemic influenza A (H1N1) 2009: epidemiological analysis of cases in a tropical/semi-arid region of Brazil

Introduction The year 2009 marked the beginning of a pandemic caused by a new variant of influenza A (H1N1). After spreading through North America, the pandemic influenza virus (H1N1) 2009 spread rapidly throughout the world. The aim of this study was to describe the clinical and epidemiological characteristics of cases of pandemic influenza in a tropical/semi-arid region of Brazil. Methods A retrospective study analyzed all suspected cases of pandemic influenza (H1N1) 2009 reported in the Ceará State through the National Information System for Notifiable Diseases during the pandemic period between 28 April, 2009 and November 25, 2010. Results A total of 616 suspected cases were notified, 58 (9.4%) in the containment phase and 558 (90.6%) in the mitigation phase. Most cases were of affected young people resident in the City of Fortaleza, the largest urban center in the State of Ceará. The most frequent symptoms presented by the cases with confirmed infection were fever, cough, myalgia, arthralgia, and nasal congestion. Mortality rate was 0.0009/1,000 inhabitants and lethality was 5.6%. Deaths were observed only in the mitigation phase. Mortality rates were similar for both sexes but were higher in the age group under 5 years. Conclusions The study suggests that the influenza A (H1N1) pandemic in this tropical/semi-arid region had a lower magnitude when compared to states in the Southern and Southeastern regions of Brazil. .

Conocimientos, actitudes y prácticas sobre la influenza A(H1N1) 2009 y la vacunación contra influenza pandémica: resultados de una encuesta poblacional / Knowledge, attitudes and practices about influenza A(H1N1) 2009, and influenza vaccine in Mexico: results of a population survey

OBJETIVO: Evaluar conocimientos, actitudes y prácticas respecto a la pandemia de influenza, con especial énfasis en la vacuna contra influenza estacional y pandémica. MATERIAL Y MÉTODOS: Estudio transversal con muestreo polietápico probabilístico, realizado durante diciembre de 2009 en residentes mayores de 18 años de la Ciudad de México (y área metropolitana), Monterrey, Guadalajara y Mérida. RESULTADOS: Se incluyeron 1 600 sujetos (48.9% masculino); 34% había recibido vacuna contra influenza estacional en años pasados, 90.6% estaba dispuesto a recibir la vacuna contra A(H1N1). La principal causa de rechazo a la vacunación fue no confiar en la vacuna (46.5%). Principales medidas preventivas identificadas por los encuestados: lavado de manos (47.5%), vacuna contra A(H1N1) (28%) y etiqueta respiratoria (19.4%). El nivel escolar (1.7, p=0.006) y edad (1.02, p<0.001) influyeron en el rechazo a la vacuna. El 82.9% de los encuestados calificó el manejo de la situación por el Gobierno Federal como bueno o muy bueno. CONCLUSIONES: La población refirió un alto porcentaje de aceptación para la vacuna de influenza pandémica durante el inicio de la campaña de vacunación en México, comparado con la reportada en otros países. La principal razón de aquéllos que la rechazan es la desconfianza hacia la vacuna.

OBJECTIVE: To assess knowledge, attitudes and practices regarding influenza pandemic, with special emphasis on issues related to influenza vaccine, seasonal and pandemic. MATERIALS AND METHODS: Cross-sectional study, probabilistic multistage sampling in patients over 18 years, residents of Mexico City (and metropolitan area), Monterrey, Guadalajara and Merida in December 2009. RESULTS: A total of 1.600 subjects (48.9% male) were interviewed, 34% had previously received seasonal flu vaccine, 90.6% were willing to be vaccinated against A(H1N1), 46.5% of those who would not receive the vaccine was because they did not trust A (H1N1), 68% considered influenza A (H1N1) as a risk for their family. Hand washing was the preventive measure most commonly reported (47.5%), secondly influenza vaccine (28%). Schooling (1.7, p=0.006) and age (1.02, p<0.001) influence rejection to get vaccine. 82.9% of respondents rate the federal government's management as good or very good. CONCLUSIONS: There was a high acceptance rate for the pandemic influenza vaccine in Mexico when compared to similar studies in other countries, the main reason for those who reject the vaccine was distrust in it.

Genetic analysis of HA gene of pandemic H1N1 2009 influenza viruses circulating in India.

The H1N1 2009 influenza pandemic took the health care workers by surprise in spite of warning about influenza pandemic. Influenza A virus has the ability to overcome immunity from previous infections through the acquisition of genetic changes by shift or drift. Thus, understanding the evolution of the viruses in human is important for the surveillance and the selection of vaccine strains. A total of 23 pandemic A/H1N1 2009 viral HA gene sequences were downloaded from NCBI submitted during March and May 2010 by NIV and were analysed. Along with that the vaccine strain A/California/07/2009 was also downloaded from NCBI. All the sequences were used to analyse the evolution of the haemagglutinin (HA) by phylogenetic analysis. The HA gene could be divided into four groups with shift from 1 to lV revealing that the HA genes of the influenza A viruses evolved in a sequential way, in comparison to vaccine strain A/California/07/2009. Amino acid sequence analysis of the HA genes of the A/H1N1 2009 isolates, revealed mutations at positions 100, 220 and additional mutations in different positions 114, 171, 179, 190, 208, 219, 222, 239, 240, 247, 251, 260 and 285 .The mutations identified showed the adaptation of the new virus to the host that could lead to genetic changes inherent to the virus resulting in a reassortant which could be catastrophic, hence continuous monitoring of strains is mandatory.

Comparative study of pandemic (H1N1) 2009, swine H1N1, and avian H3N2 influenza viral infections in quails

Quail has been proposed to be an intermediate host of influenza A viruses. However, information on the susceptibility and pathogenicity of pandemic H1N1 2009 (pH1N1) and swine influenza viruses in quails is limited. In this study, the pathogenicity, virus shedding, and transmission characteristics of pH1N1, swine H1N1 (swH1N1), and avian H3N2 (dkH3N2) influenza viruses in quails was examined. Three groups of 15 quails were inoculated with each virus and evaluated for clinical signs, virus shedding and transmission, pathological changes, and serological responses. None of the 75 inoculated (n = 45), contact exposed (n = 15), or negative control (n = 15) quails developed any clinical signs. In contrast to the low virus shedding titers observed from the swH1N1-inoculated quails, birds inoculated with dkH3N2 and pH1N1 shed relatively high titers of virus predominantly from the respiratory tract until 5 and 7 DPI, respectively, that were rarely transmitted to the contact quails. Gross and histopathological lesions were observed in the respiratory and intestinal tracts of quail inoculated with either pH1N1 or dkH3N2, indicating that these viruses were more pathogenic than swH1N1. Sero-conversions were detected 7 DPI in two out of five pH1N1-inoculated quails, three out of five quails inoculated with swH1N1, and four out of five swH1N1-infected contact birds. Taken together, this study demonstrated that quails were more susceptible to infection with pH1N1 and dkH3N2 than swH1N1.

Guillain-Barre Syndrome With Treatment-Related Fluctuations

No abstract available.

Clinical and Laboratory Characteristics of Pandemic Influenza A/H1N1 2009 Infection among Patients with Malignancy in Korea / 감염과화학요법

BACKGROUND: Patients with malignancy are considered to be at high risk of severe pandemic influenza A/H1N1 2009. This study was conducted to identify the severity of pandemic influenza A/H1N1 2009 among patients with malignancy. MATERIALS AND METHODS: Between August 2009 and December 2009, we reviewed clinical data and medical records of 31 patients with malignancy and 63 hospitalized patients without malignancy. RESULTS: Eighty-three patients with laboratory-confirmed pandemic influenza A/H1N1 2009 were admitted. The rate of ICU admission was higher among patients with malignancy (without malignancy 13% vs with malignancy 35%, P=0.024). The mortality rate was higher among patients with malignancy (without malignancy 6% vs with malignancy 25%, P=0.033). Patients using immunosuppressants showed a higher rate of lower respiratory tract infection (83% vs 24%, P=0.013). CONCLUSIONS: Pandemic influenza A/H1N1 2009 in patients with malignancy was more severe than in patients without malignancy.

Epidemiological characteristics on the clustering nature of pandemic (H1N1) 2009 in China / 中华流行病学杂志

Objective To study the epidemiological characteristics on the clustering nature of pandemic (H1N1) 2009 in China.Methods Time and place distribution of pandemic (H1N1) 2009on the nature of clustering through data from Public Health Emergency Management Information System were described.Results As of August 10,2010,2773 pandemic (H1N1) 2009 clusters,a total of 77363 cases (including 20 deaths) were reported in the mainland of China.The most reported number of clusters was from schools and kindergartens with the total number of 2498 (accounted for 90.08％ of the total number).Middle schools appeared the have the most clusters (1223,accounting for 48.96％ ).The number of clusters reported in the southern provinces (cities) accounted for 77.03％ of the total,and was more than that in the northern provinces (cities).Two reported peaks in the southern provinces (cities) were in June and November,2009,respectively.There was only one reported peakin the northern provinces in September,2009.Conclusion Time and place distribution characteristics on the clusters of pandemic (H1N1) 2009 were similar to the seasonal influenza,but the beginning of winter peak was much earlier and intensity of reporting was much higher on the clusters of pandemic (H1N1 ) 2009 than that of seasonal influenza.

Respiratory virus infections among hospitalized patients with suspected influenza A H1N1 2009 virus during the first pandemic wave in Brazil

INTRODUCTION: During the first pandemic wave of the influenza A H1N1 2009 virus, morbidity was particularly high in Brazil. Hospitalizations resulting from severe respiratory disease due to suspected influenza-like illness created an opportunity to identify other respiratory viruses causing lower respiratory infections. OBJECTIVE: The purpose of this study was to assess viral etiologies among samples collected during the first pandemic wave of H1N1 2009 from hospitalized patients with suspected cases in a Brazilian Sentinel Hospital. PATIENTS AND METHODS: Viral etiologies were investigated in samples from 98 children and 61 adults with fever, cough and dyspnea who were admitted to São Paulo Sentinel Hospital with suspected H1N1 infection. RESULTS: From August to November 2009, in 19.5 percent (31/159) of the samples 2009 H1N1 virus was detected with 23 percent (14/61) in adults (median age 25 years, range: 14-55 years) and 18.4 percent (17/92) in children (median age 5 years, range: 4 months - 11 years). Among the negative samples, a wide range of causative etiologic agents was identified. Human rhinovirus was the most frequent virus (23.91 percent) in children and human metapneumovirus (11.48 percent) was the second most frequent in adults, following 2009 H1N1 virus (22.95 percent). CONCLUSION: These data highlight the need to diagnose other viral infections that can co-circulate with influenza and may have been neglected by physicians as causes of severe respiratory diseases.

Surveillance of hospitalizations with pandemic A(H1N1) 2009 influenza infection in Queensland, Australia

OBJECTIVE: To describe the demographic and clinical characteristics of patients hospitalized with pandemic A(H1N1) 2009 infection in Queensland, Australia between 25 May and 3 October 2009 and to examine the relationship between timing of antiviral treatment and severity of illness. METHOD: Using data from the Queensland Health EpiLog information system, descriptive analysis and logistic regression modelling were used to describe and model factors which influence patient outcomes (death, admission to intensive care unit and/or special care unit). Data on patients admitted to hospital in Queensland with confirmed pandemic A(H1N1) 2009 infection were included in this analysis. RESULTS: 1236 patients with pandemic A(H1N1) 2009 infection were admitted to hospitals in Queensland during the study period. Of the total group: 15% were admitted to an intensive care unit or special care unit; 3% died; 34% were under the age of 18 years and 8% were 65 years of age or older; and 55% had at least one underlying medical condition. Among the 842 patients for whom data were available regarding the use of antiviral drugs, antiviral treatment was initiated in 737 (87.5%) patients, treatment commenced at a median of one day (range 1–33 days) after onset of illness. Admission to an intensive care unit or special care unit (ICU/SCU) or death was significantly associated with increased age, lack of timeliness of antiviral treatment, chronic renal disease and morbid obesity. DISCUSSON: Early antiviral treatment was significantly associated with lower likelihood of ICU/SCU admission or death. Early antiviral treatment for influenza cases may therefore have important public health implications.

Continued dominance of pandemic A(H1N1) 2009 influenza in Victoria, Australia in 2010

The 2010 Victorian influenza season was characterized by normal seasonal influenza activity and the dominance of the pandemic A(H1N1) 2009 strain. General Practice Sentinel Surveillance rates peaked at 9.4 ILI cases per 1000 consultations in week 36 for metropolitan practices, and at 10.5 ILI cases per 1000 in the following week for rural practices. Of the 678 ILI cases, 23% were vaccinated, a significantly higher percentage than in previous years. A significantly higher percentage of ILI patients were swabbed in 2010 compared to 2003–2008, but similar to 2009, with a similar percentage being positive for influenza as in previous years. Vaccination rates increased with patient age. Melbourne Medical Deputising Service rates peaked in week 35 at 19.1 ILI cases per 1000 consultations. Of the 1914 cases of influenza notified to the Department of Health, Victoria, 1812 (95%) were influenza A infections – 1001 (55%) pandemic A(H1N1) 2009, 4 (<  1%) A(H3N2) and 807 (45%) not subtyped; 88 (5%) were influenza B; and 14 (<  1%) were influenza A and B co-infections. The World Health Organization Collaborating Centre for Reference and Research on Influenza tested 403 isolates of which 261 were positive for influenza, 250 of which were influenza A and 11 were influenza B. Ninety-two per cent of the influenza A viruses were pandemic A(H1N1) 2009, and following antigenic analysis all of these were found to be similar to the current vaccine strain. Three viruses (0.9%) were found to be oseltamivir resistant due to an H275Y mutation in the neuraminidase gene.

Comparison of secondary attack rates in ger and apartment areas, Mongolia, November 2009 / Монголын Анагаах Ухаан

Background: Since its first identification of Pandemic H1N1 2009 in Oct 12, 09 in Mongolia, the cases have increased dramatically spreading in much of cities and provinces of Mongolia. We aimed to identify and compare the transmissibility of the infection in different household settings, so to add understanding of special characteristics of this infection.Methods: We selected 20 laboratory confirmed 2009 H1N1 influenza as the index cases from the National Surveillance System. We searched for Influenza like illness (ILI) cases in the households by questioning index-cases and household-contacts. Secondary case was defined as household-contact who developed one of the signs such as fever, dry cough, sore throat, runny nose and diarrhea within one week of symptom onset in index case. We calculated and compared attack rates in ger and apartment areas.Results: Transmissibility of 2009 H1N1 influenza was studied in 20 households. Each half was from ger and apartment residency of Ulaanbaatar city, Mongolia. The study involved 20 indexcases and 72 household-contacts. Secondary transmission occurred in 13 (65%) households with 22 (30.5%) household cases of probable Pandemic H1N1 influenza virus infection. The incidence in ger and apartment areas was 36.1% and 25.0% relatively. Cases in ger residency were 1.2 times more likely than in apartment residency to develop ILI (RR = 1.2, 95%CI: 0.86- 1.60).Conclusions: Overall secondary attack rate in this study was 30.5%, which is similar to that of 30% secondary attack rate for laboratory-confirmed 2009 H1N1 influenza in tourist group members in China. Though statistically not significant, the risk estimation of secondary ILI compared in ger and apartment residency indicates ger area residents have 20% higher risk for ILI development after illness in index case.

A Prediction Rule to Identify Severe Cases among Adult Patients Hospitalized with Pandemic Influenza A (H1N1) 2009

The purpose of this study was to establish a prediction rule for severe illness in adult patients hospitalized with pandemic influenza A (H1N1) 2009. At the time of initial presentation, the baseline characteristics of those with severe illness (i.e., admission to intensive care unit, mechanical ventilation, or death) were compared to those of patients with non-severe illnesses. A total of 709 adults hospitalized with pandemic influenza A (H1N1) 2009 were included: 75 severe and 634 non-severe cases. The multivariate analysis demonstrated that altered mental status, hypoxia (PaO2/FiO2 or = 65 yr) were independent risk factors for severe cases (all P or = 2 risk factors had a higher sensitivity, specificity, positive predictive value and negative predictive value than an APACHE II score of > or = 13. As a prediction rule, the presence of > or = 2 these risk factors is a powerful and easy-to-use predictor of the severity in adult patients hospitalized with pandemic influenza A (H1N1) 2009.

Pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1): An experience from a tertiary care center in north India.

Objectives To describe our experience in children hospitalized with the pandemic Influenza A (H1N1) from Northern India. Methods The retrospective case study was conducted at the Pediatric ward and Pediatric Intensive Care Unit (PICU) dedicated to the children (aged 18 years or younger) with influenza-like illness (ILI) with positive laboratory test results for pandemic H1N1 by reverse-transcriptase polymerasechain- reaction assay. Results Between August 2009 and January 2010, a total of 100 children were hospitalized with suspected 2009 H1N1 influenza with Category “C” as described by the Government of India. Twenty five patients were positive for H1N1 and 9 for seasonal influenza A. The most common presentation (H1N1 positive) was with fever (100%), cough (100%), coryza (52%), respiratory distress (88%), vomiting (28%) and diarrhea (16%). One child presented with hypernatremic dehydration and seizures (Serum sodium 174 meq/l). Of the H1N1 positive hospitalized children, 7 (28%) had respiratory failure and required PICU admission, 4 (16%) required mechanical ventilation, and 3 (12%) died. The major radiological findings were bilateral pulmonary infiltrates and consolidation. All patients were treated with oral Oseltamivir suspension or capsule as per appropriate weigh band and supportive care as required. Two deaths were caused by refractory hypoxemia and one by refractory shock. Conclusions The exact incidence of Pandemic 2009 H1N1 influenza on morbidity and mortality is difficult to calculate since only Category “C” patients were screened.

Pandemic influenza A(H1N1) 2009 outbreak in a residential school at Panchgani, Maharashtra, India.

Background & objectives: An outbreak of influenza was investigated between June 24 and July 30, 2009 in a residential school at Panchgani, Maharashtra, India. The objectives were to determine the aetiology, study the clinical features in the affected individuals and, important epidemiological and environmental factors. The nature of public health response and effectiveness of the control measures were also evaluated. Methods: Real time reverse transcriptase polymerase chain reaction was performed on throat swabs collected from 82 suspected cases to determine the influenza types (A or B) and sub-types [pandemic (H1N1) 2009, as well as seasonal influenza H1N1, H3N2]. Haemagglutination inhibition assay was performed on serum samples collected from entire school population (N = 415) to detect antibodies for pandemic (H1N1) 2009, seasonal H1N1, H3N2 and influenza B/Yamagata and B/Victoria lineages. Antibody titres ≥ 10 for pandemic (H1N1) 2009 and ≥ 20 for seasonal influenza A and B were considered as positive for these viruses. Results: Clinical attack rate for influenza-like illness was 71.1 per cent (295/415). The attack rate for pandemic (H1N1) 2009 cases was 42.4 per cent (176/415). Throat swabs were collected from 82 cases, of which pandemic (H1N1) 2009 virus was detected in 15 (18.3%), influenza type A in (6) 7.4 per cent and influenza type B only in one case. A serosurvey carried out showed haemagglutination inhibition antibodies to pandemic (H1N1) 2009 in 52 per cent (216) subjects in the school and 9 per cent (22) in the community. Interpretation & conclusion: Our findings confirmed an outbreak of pandemic (H1N1) 2009 due to local transmission among students in a residential school at Panchgani, Maharashtra, India.

Caracterización clínica de adultos menores y mayores de 50 años hospitalizados por influenza A H1N1 2009 en un centro hospitalario privado en Santiago, Chile / Clinical features of adults younger and older than 50 years hospitalized with influenza A H1N1 2009 in a private hospital in Santiago, Chile

Introduction: The new pandemic influenza A H1N1 2009 virus has shown a different clinical behavior in different age groups. Objective: To describe the clinical features of adult patients hospitalized with influenza AH1N1 2009 and compare the clinical and demographic variables among adults < 50 years and over 50 years old. Patients and Method: We included hospitalized patients between May 17 and July 17, 2009 confirmed by polymerase chain reaction (PCR) and/or rapid test for influenza A. Results: 124 patients were hospitalized with a median age of 33 years (range: 15-82 years). 36 percent had comorbidities and the main symptoms were fever, cough, myalgia and sore throat. There were 16 cases with pneumonia. From 124 patients, 77 percent were A-49 and 23 percentA-50, with comorbidity of 21 percent and 86 percent, respectively. There were no fatalities. Conclusions: Hospitalized patients had mild to moderate disease, a benign course and short hospitalization stay. There were more hospitalizations in A-49 and higher comorbidity in A-50.

Introducción: El nuevo virus influenza AH1N1 2009 ha mostrado un comportamiento clínico diferente en distintos grupos etáreos. Objetivo: Describir las características clínicas de los pacientes adultos hospitalizados con influenza A H1N1 2009 y comparar las variables clínicas y demográficas entre menores y mayores de 50 años. Pacientes y Método: Se incluyeron los pacientes hospitalizados entre el 17 de mayo y 17 de julio del 2009 confirmados por reacción de polimerasa en cadena (RPC) y/o pruebas rápidas para influenza A. Resultados: Se hospitalizaron 124 pacientes con una mediana de edad de 33 años (rango: 15-82 años). Un 36 por ciento presentó co-morbilidad y los síntomas principales fueron: fiebre, tos, mialgias y odinofagia. Hubo 16 casos con neumonía. Del total, 77 por ciento fueron < 50 y 23 por ciento ≥ 50 años. Tenían co-morbilidades 21 por ciento en el grupo < 50 versus 86 por ciento en ≥ 50 años. No hubo casos fatales. Conclusiones: Los pacientes presentaron una enfermedad leve a moderada, de curso benigno y corta hospitalización. Hubo más hospitalizados en < 50 y mayor co-morbilidad en ≥ 50 años.

Influenza pandémica a un año de la primera ola: ¿qué podemos decir ahora? / Pandemic influenza one year after the first wave: what did we learn?

During year 2009 our nation experimented the first influenza pandemic wave due to the novel influenza A (H1N1) 2009 virus that emerged in the Northern hemisphere at the end of April, 2009. Estimated attack rate was about 6 to 12 percent affecting mainly to schoolchildren who presented with a mild disease. Age groups with highest risk of hospitalization were elderly people and children under 5 years old. Elderly patients and patients with co-morbidities had the highest risk to die. We have learnt that clinical diagnosis of influenza has a laboratory confirmation in about 80 percent of cases but its correlation is lower in kids under 5 years old, especially in infants when RSV co-circulates with influenza virus. Laboratory diagnostic methods like DFA and immuno-cromatography have about 80 percent of sensitivity but a significantly lower rate in elderly patients compared to PCR. The clinical impact of this new virus justifies the recommendation to vaccinate traditionally established risk groups and to prescribe antiviral treatment to patients that acquire severe influenza or have risk factors to progress to complications.

Durante el año 2009 nuestro país vivió la primera ola pandémica causada por el nuevo virus de influenza A (H1N1) 2009 aparecido en el hemisferio norte a fines de abril del ese año. La tasa de ataque estimada fue entre 6 a 12 por ciento afectando más frecuentemente a los escolares quienes presentaron una enfermedad leve. Los grupos etáreos con mayor riesgo de hospitalización fueron los adultos mayores y los niños bajo 5 años de edad. Tuvieron mayor riesgo de fallecer los adultos mayores y aquellas personas con una co-morbilidad asociada. Aprendimos que el diagnóstico clínico de influenza se confirma por laboratorio en alrededor del 80 por ciento pero tiene una baja correlación en los niños bajo 5 años de edad, especialmente en lactantes bajo 1 año de edad, al circular concomitantemente con VRS. Los métodos de diagnóstico como la IFD y los inmunocromatográficos tienen una sensibilidad que no supera el 80 por ciento y es muy baja en los adultos mayores cuando se compara con PCR. Dado el impacto clínico de este nuevo virus se justifica el uso de vacunación en los grupos de riesgo previamente descritos y el tratamiento con antivirales en los pacientes que cursan con enfermedad grave o con riesgo de evolucionar a una enfermedad más complicada.