Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine

Please cite this paper as: Deng et al. (2012). Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine. Influenza and Other Respiratory Viruses 6(3), e42–e47. Background Swine have receptors for both human and avian influenza viruses and are a natural host for influenza A viruses. The 2009 influenza A(H1N1) pandemic (H1N1pdm) virus that was derived from avian, human and swine influenza viruses has infected pigs in various countries. Objectives To investigate the relationship between the H1N1pdm viruses isolated from piggery outbreaks in Australia and human samples associated with one of the outbreaks by phylogenetic analysis, and to determine whether there was any reassortment event occurring during the human‐pig interspecies transmission. Methods Real‐time RT‐PCR and full genome sequencing were carried out on RNA isolated from nasal swabs and/or virus cultures. Phylogenetic analysis was performed using the Geneious package. Results The influenza H1N1pdm outbreaks were detected in three pig farms located in three different states in Australia. Further analysis of the Queensland outbreak led to the identification of two distinct virus strains in the pigs. Two staff working in the same piggery were also infected with the same two strains found in the pigs. Full genome sequence analysis on the viruses isolated from pigs and humans did not identify any reassortment of these H1N1pdm viruses with seasonal or avian influenza A viruses. Conclusions This is the first report of swine infected with influenza in Australia and marked the end of the influenza‐free era for the Australian swine industry. Although no reassortment was detected in these cases, the ability of these viruses to cross between pigs and humans highlights the importance of monitoring swine for novel influenza infections.     

Canada in the face of the 2009 H1N1 pandemic

Please cite this paper as: Moghadas et al. (2011) Canada in the face of the 2009 H1N1 pandemic. Influenza and Other Respiratory Viruses 5(2), 83–88. Background Initial public health responses to the 2009 influenza H1N1 pandemic were based on difficult decisions in the face of substantial uncertainty. Policy effectiveness depends critically on such decisions, and future planning for maximum protection of community health requires understanding of the impact of public health responses in observed scenarios. Objectives In alignment with the objectives of the Pandemic Influenza Outbreak Research Modelling Team (Pan‐InfORM) and the Centre for Disease Modelling (CDM), a focused workshop was organized to: (i) evaluate Canada's response to the spring and autumn waves of the novel H1N1 pandemic; (ii) learn lessons from public health responses, and identify challenges that await public health planners and decision‐makers; and (iii) understand how best to integrate resources to overcome these challenges. Main outcome measures We report on key presentations and discussions that took place to achieve the objectives of the workshop. Conclusions Future emerging infectious diseases are likely to bring far greater challenges than those imposed by the 2009 H1N1 pandemic. Canada must address these challenges and enhance its capacity for emergency responses by integrating modelling, surveillance, planning, and decision‐making.     

甲型H1N1与季节性H1N1流感病毒血凝素基因比较分析

目的分析泰安市2008～2009年度季节性流感与2009年度甲型H1N1流感病原学检测结果 ,比较季节性H1N1与甲型H1N1血凝素基因变异情况。方法选择国家级流感监测哨点医院以及暴发疫情的疫点,采集流感样病例的鼻咽拭子标本,通过RealtimePCR进行病毒检测,用MDCK细胞进行病毒分离,通过RT-PCR扩增血凝素HA1片段的基因并测序,利用生物信息学进行序列分析。结果 2008～2009年共检测鼻咽拭子标本283份,分离出流感病毒33株,分离阳性率为11.67%,其中季节性H1N1亚型31株。2009年5月1日～12月31日,检测鼻咽拭子标本996份,流感核酸检测阳性417份,阳性率为41.86%,其中甲型H1N1337份,季节性H1N1亚型1份。6株季节性H1N1病毒均在多个氨基酸位点上发生变异,与疫苗株A/Brisbane/59/2007(H1N1)比较,有11个位点发生了突变,其中5个位点位于抗原决定簇上;测序成功的6株甲型H1N1病毒在多个氨基酸位点发生变异,与疫苗株A/California/07/2009(H1N1)比较,有6个位点发生突变,其中1个位点位于抗原决定簇的B区。结论 2008～2009年度季节性H1N1为优势株,甲流暴发后,甲型H1N1成为绝对优势毒株。季节性H1N1分离株有多处氨基酸替换,抗原决定簇B区变异频繁;甲型H1N1病毒分离株的基因有变异,但关键位点第222位仍为D(天冬氨酸),与疫苗株相比抗原决定簇的关键位点变化不大。     

Triple‐reassortant influenza A virus with H3 of human seasonal origin,NA of swine origin,and internal A(H1N1) pandemic 2009 genes is established in Danish pigs

This report describes a triple‐reassortant influenza A virus with a HA that resembles H3 of human seasonal influenza from 2004 to 2005, N2 from influenza A virus already established in swine, and the internal gene cassette from A(H1N1)pdm09 has spread in Danish pig herds. The virus has been detected in several Danish pig herds during the last 2‐3 years and may possess a challenge for human as well as animal health.     

北京市2009年甲型H1N1流感患者密切接触者的流行病学特点

目的 了解和掌握甲型H1N1流感患者密切接触者的流行病学特点,为未来流感大流行的防控提供可参考的依据.方法 选择2009年5月16日至9月15日北京发现的613例具有明确密切接触者信息的甲型H1N1流感患者(原发病例)及其密切接触者7099名作为研究对象,根据其流行病学凋查资料和标本资料收集相关信息,对甲型H1N1流感密切接触者的感染情况进行描述性分析.通过χ2检验对不同类型甲型H1N1流感密切接触者的感染情况进行比较分析.结果 613例原发病例中,男348例(56.8%),女265例(43.2%),年龄为1～75岁,中位年龄为20岁.7099名密切接触者中,男3518名(49.6%),女3514名(49.5%),性别不详67名(0.9%),年龄为0～99岁,中位年龄为27岁.甲型H1N1流感原发病例密切接触者的感染率为2.4%(167/7099).随着密切接触者年龄的增长,甲型H1N1流感病毒感染率呈现明显下降的趋势(χ2=27.87,P＜0.001);以不同方式与原发病例接触的密切接触者之间的感染率比较差异有统计学意义(χ2=109.76,P＜0.001).甲型H1N1流感原发病例的密切接触者中,隐性感染病例占14.4%(24/167).对于密切接触者中出现症状的感染者,最早可在发病前4.5 d的咽拭子标本中检测到病毒;病毒传代时间的中位天数为2.4 d.结论 甲型H1N1流感原发病例密切接触者的病毒感染率较低;不同年龄及不同接触方式的密切接触者之间的感染率存在差异;14.4%的甲型H1N1流感病毒感染者为隐性感染;甲型H1N1流感病例有可能在发病前4.5 d即具有传染性.

Abstract：

Objective To examine the epidemiologieal characteristics of infection for close contacts of pandemic(H1N1)2009 and to provide scienlific evidence for preparedness and response for the next pandemic.Methotis A total of 613 index cases with clear information of close contacts and their 7099 close contacts,determined between May 16 and September 15,2009,were inchded in this study.Based on data of epidemioiogical investigation,sampling and test of index cases and close contacts,the characteristics of infection for close contacts were described.Results 56.8%(348/613)of the index cases were male,and 43.2%(265/613)were female,and the median age was 20 years(range:1-75 years).49.6%(3518/7099)of the close contacts were male,and 49.5%(3514/7099)were female,but the sex information of 0.9%(67/7099)could not be recorded.The median age of the close contacts was 27 years(range:0-99 years).2.4%(167/7099)of close contacts were infected.The attack rates decreased with inereasing age of close contacts(χ2=27.87,P＜0.001),and were significantly difierent between various contact patterns of close contact(χ2=109.76,P＜0.001).14.4%of the infected close contacts were asymptomatic.For close contacts with symptomatic infection,vims could be shed 4.5 days before illness onset,and the median generation time was 2.4 days.Conclusion The attack rate of close contacts was very low;and the attack rates were different between various ages and contact patterns of close contacts.In this series 14%of cases with pandemic(H1N1)2009 were asymptomatic.The symptomatic cases might have infectivity 1 day earlier before illness onset.     

Systematic review of clinical and epidemiological features of the pandemic influenza A (H1N1) 2009

The aim of this systematic review was to summarise the clinical and epidemiological features of the pandemic influenza A (H1N1) 2009. We did a systematic search of published literature reporting clinical features of laboratory-confirmed pandemic influenza A (H1N1) 2009 from 1 April 2009 to 31 January 2010. Forty-four articles met our inclusion criteria for the review. The calculated weighted mean age of confirmed cases was 18·1 years, with the median ranging from 12 to 44 years. Cough (84·9%), fever (84·7%), headache (66·5%), runny nose (60·1%) and muscle pain (58·1%) were the most common symptoms of confirmed cases. One or more pre-existing chronic medical conditions were found in 18·4% of cases. Almost two-thirds (64%) of cases were aged between 10 and 29 years, 5·1% were aged over 50 years and only 1·1% were aged over 60 years. The confirmed case fatality ratio was 2·9% (95% CI 0·0-6·7%), an extracted average from 12 of 42 studies reporting fatal cases (937 fatal cases among 31,980 confirmed cases), which gives an overall estimated infected case fatality ratio of 0·02%. Early in the pandemic, disease occurred overwhelmingly in children and younger adults, with cough and fever as the most prevalent clinical symptoms of the confirmed cases. A high infection rate in children and young adults, with sparing of the elderly population, has implications for pandemic influenza management and control policies.     

新疆甲型H1N1流行性感冒住院患者临床特征及并发心肌损害分析

目的 探讨新疆甲型H1N1流行性感冒(流感)流行期间住院患者临床特征及心肌损害的特点.方法 回顾性收集2009年8月至2010年1月新疆医科大学第一附属医院和新疆各地收治的确诊为甲型H1N1流感病例的资料.计量资料采用t检验,计数资料用卡方检验.结果 258例甲型H1N1流感患者中,普通型164例.重症型94例,其临床特点以发热、咳嗽、咳痰、全身肌肉关节酸痛、咽痛等为主.94例重症型表现为高热、呼吸困难、紫绀、低氧血症、双侧肺炎等,死亡22例,病死率为23.4%;主要死因为呼吸衰竭并多器官功能衰竭或心功能衰竭.76%患者伴有各种慢性疾病,15例妊娠者中有12例发展为重症型.与普通型比较,有基础疾病的患者病情重,重症型患者心电图、血WBC、血糖、AST、肌酸激酶、肌酸激酶同工酶MB、α羟丁酸脱氢酶和乳酸脱氢酶等异常比例高,重症患者CD4+/CD8+T淋巴细胞比值更低(1.23±0.56比0.99±0.53,t=3.543,P=0.039).结论 新疆甲型H1N1流感重症型患者原有慢性疾病、妊娠、心肌酶与心电图同时异常和CD4+/CD8+T淋巴细胞比值降低者所占比例更多.

Abstract：

Objective To explore the clinical characteristics and myocardial damage of the influenza A (H1N1) cases in Xinjiang. Methods Informations related to the influenza A (H1N1) cases were respectively collected from hospitalized cases in Xinjiang region. Measurement data were analyzed using t test and enumeration data were analyzed using chi square test. Results A total of 258 patients with influenza A (H1N1) were reported from Aug. 2009 to Jan. 2010, including 164 cases of common type and 94 of severe type. The main symptoms of the patients included high fever, cough,expectoration, angina and sore throat. Severe cases presented with high fever, dyspnea, cyanosis,hypoxemia and bilateral pneumonia. Twenty-two cases died of severe form with mortality rate of 23. 4%(22/94). The main causes of death were respiratory failure complicated with multiple organ failure or heart failure. Among severe cases, 76% had underlying chronic diseases and 12 out of 15 pregnant cases developed severe type. Compared with common type cases, more severe cases had underlying diseases and the abnormal rates of electrocardiogram (ECG), blood leukocyte counts, blood glucose, aspertate aminotransferase (AST), creatine kinase (CK), CK-MB, α-hydroxybutyrate dehydrogenase (α-HBDH) and lactic dehydrogenase (LDH) were higher; while the ratio of CD4+/ CD8+T lymphocytes was much lower (1. 23 ± 0. 56 vs 0. 99 ± 0. 53 ; t = 3. 543, P = 0.039). Conclusions Among sever cases with influenza A (H1N1) in Xinjiang, the proportion of cases with underlying diseases, pregnancy, abnormal myocardial enzymes and ECG, lower CD4+/CD8+ ratio are relatively high.     

Factors associated with severe illness in pandemic 2009 influenza a (H1N1) infection: implications for triage in primary and secondary care

Pandemic (H1N1) 2009 influenza virus (pH1N1/09) infection spread rapidly around the globe, leading to a phase 6 pandemic level of alert declared in June 2009. The WHO declared the end of the pandemic in August 2010. Although for the majority of infected patients, it manifest as a mild, self-limiting illness, a proportion appeared to follow an adverse clinical course, requiring higher level care and aggressive management strategies. Experience with previous pandemics suggests that H1N1 will continue to circulate for many years. The aim of this review is to evaluate data from published case series reporting patients with pH1N1/09 influenza to identify clinical markers of severe disease. Comorbid illnesses including chronic lung disease, obesity and pregnancy have been shown to confer increased risk of severe infection. Admission vital signs, laboratory investigations and chest radiographic features can guide admitting clinicians to stratify patients’ risk of severe disease, however, the currently available severity scoring tools have only a limited role in risk assessment. Knowledge of high risk parameters remains important for clinicians triaging patients with suspected pH1N1/09 influenza and to inform strategies for future pandemics.     

Risk factors for pandemic H1N1 2009 infection in healthcare personnel of four general hospitals

To characterize an outbreak of pandemic H1N1 2009 among healthcare personnel (HCP), we conducted a cross-sectional survey of HCP who had worked in four general hospitals during the outbreak. More than one-quarter of responding HCP (27.6%) had influenza-like illness (ILI) during the outbreak. The estimated infection rate of pandemic H1N1 2009 was 9.1% in the study of HCP. Independent risk factors for ILI were female gender, <40 years of age, the presence of chronic diseases associated with influenza complications, having family members with ILI or pandemic H1N1 2009, and working in influenza outpatient, influenza inpatient, non-influenza outpatient or emergency departments. During the outbreak of pandemic H1N1 2009, HCP frequently had ILI or the influenza infection. The development of the influenza infection in HCP was associated with some of their baseline characteristics, occupational risk factors, and non-occupational ones during the outbreak.     

关于流感病毒毒性评估

病毒在人群中的流行速度或病毒在人群传播过程中所显示的毒力主要反应出人群的遗传异质性.当一个病毒性疾病在不同亚群之间的发病率和死亡率不表现出明显差异时,该病毒的毒力可能十分强大.相反,当这些差异存在时,则其毒力较低;差异种类越多,差异程度越大,则毒力越小.     

北京市2009年甲型H1N1流行性感冒危重症与死亡病例流行病学特征及其影响因素分析

目的 了解北京市2009年甲型H1N1流行性感冒(流感)危重症与死亡病例的流行病学特征,探讨影响甲型H1N1流感病情严重程度的主要因素.方法 利用北京市2009年甲型H1N1流感病例个案信息进行描述性分析和多因素Logistic回归分析.结果 北京市2009年甲型H1N1流感感染率为66.1/10万,25～60岁组人群感染率最高,为86.8/10万.0～5岁组和60岁以上年龄组危重症感染率(12.5/10万,3.9/10万)、死亡率(0.9/10万,0.7/10万)和病死率(2.4%,3.3%)较高.549例危重症病例中学龄前儿童110例,比例最高,占20.0%,69例死亡病例中离、退休人员17例,比例最高,占24.6%.超过70.0%的危重症和死亡病例均在发病后2 d内到医院就诊.危重症病例和死亡病例中,均以有心血管疾病的病例比例最高,其次为慢性肺部疾病.多因素Logistic回归分析显示,甲型H1N1流感病例中,60岁以上、慢性肺部疾病及心血管疾病可能导致其病情较重,OR值分别为3.586(95%CI 1.586～8.117)、2.126(95%CI 1.178～3.835)和1.954(95%CI 1.126～3.391).结论 60岁以上、伴心血管疾病及慢性肺部疾病等因素可能加重甲型H1N1流感病例病情.     

四川省2009甲型H1N1流感的流行病学特征

目的分析四川地区甲型H1N1流感流行病学特点,为今后新发传染病的防控提供参考。方法回顾性分析我院2009年收治的271例甲型H1N1流感病例的来源、年龄及时间分布。结果 1.271例甲型H1N1流感病例,男∶女为1.09∶1,随着病情加重发病年龄逐渐增加,病程亦逐渐延长;2.轻症患者均无基础疾病,危重症患者基础疾病较重症患者多且重;3.绝大多数患者年龄在10~30岁（211例,77.87%）,轻症及重症中无≤2岁及≥65岁的患者,危重症中≥65岁者2例;4.疫情早期（5~9月）患者均为轻症,以输入病例为主（52例,19.19%）,疫情后期以本土暴发病例为主（9月以后）有危重症出现。结论新发传染病疫情早期以轻症、输入病例为主,后期随着社区聚集性疫情,有重危症患者出现;患者年龄、基础疾病是该疾病严重程度的重要影响因素。     

Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests

Please cite this paper as: Gao et al. (2011) Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests. Influenza and Other Respiratory Viruses 6(3), e30–e34. Background The performance of rapid influenza diagnostic tests (RIDTs) in detecting influenza A(H1N1) 2009 has varied widely. Evaluations of RIDTs among infected individuals across all age groups have not been described in depth. Objectives Determine RIDT clinical sensitivity in comparison with influenza detection using real‐time RT‐PCR among patients infected with influenza A(H1N1) 2009 across all age groups. Study design This study analyzed respiratory specimens received by the New Hampshire Public Health Laboratories (NHPHL) from September 1, 2009, through December 31, 2009. RIDT performance was evaluated among different age groups of patients determined to be infected with influenza A (H1N1) 2009, and the association between age and RIDT sensitivity was determined. Results Of 1373 specimens examined, 269 tested positive for influenza A(H1N1) 2009 by real‐time RT‐PCR (rRT‐PCR) and had RIDT results available. Overall clinical sensitivity and specificity of RIDTs were 53·9 and 98·5%, respectively. By age group, clinical sensitivity was 85·7% in patients <2 years old, 60·3% in patients between 2‐ and 39 years old, and 33·3% in patients aged 40 and older. Logistic regression analysis indicated that increasing age was negatively associated with RIDT performance. Conclusion Rapid influenza diagnostic test sensitivity decreased significantly with increasing age. Findings from this study may impact a clinician’s interpretation of RIDT test results and ultimately have implications in clinical decision‐making.     

磷酸奥司他韦治疗甲型H1N1流感临床研究

目的分析奥司他韦在临床治疗甲型H1NI流感患者过程中对病情变化及预后的影响。方法采用回顾性分析方法对我院257例甲型H1N1流感患者的临床资料。结果257例患者根据病情划分为普通型、重症型和危重型3组。三组患者年龄、发热时间和平均住院时间比较,差异有显著性（P〈0．001）,使用奥司他韦治疗的比例分别为20％、28％和81％。在发病48小时内开始奥司他韦治疗患者与发病48小时后开始治疗患者比较,发热持续时问和病毒核酸阳性持续时间比较差异有显著性（P〈0．05）。死亡患者与存活患者开始奥司他韦治疗时间比较明显延迟,两组比较差异有显著性（P〈0．001）。结论发病后48小时以后开始磷酸奥司他韦治疗可能导致发热等症状和病毒核酸阳性持续时间延长,并可能导致病死率增加。     

Transmission of pandemic influenza H1N1 (2009) in Vietnamese swine in 2009-2010

Please cite this paper as: Trevennec et al. (2012) Transmission of pandemic influenza H1N1 (2009) in Vietnamese swine in 2009–2010. Influenza and Other Respiratory Viruses 6(5), 348–357. Background The pandemic of 2009 was caused by an H1N1 (H1N1pdm) virus of swine origin. This pandemic virus has repeatedly infected swine through reverse zoonosis, although the extent of such infection in swine remains unclear. Objective This study targets small and commercial pig producers in North Vietnam, in order to estimate the extent of H1N1pdm infection in swine and to identify the risk factors of infection. Methods Virologic and serologic surveillance of swine was carried out in 2009–2010 in pig farms (38 swabs and 1732 sera) and at a pig slaughterhouse (710 swabs and 459 sera) in North Vietnam. The sera were screened using a influenza type A‐reactive ELISA assay, and positive sera were tested using hemagglutination inhibition tests for antibody to a panel of H1‐subtype viruses representing pandemic (H1N1) 2009 (H1N1pdm), triple reassortant (TRIG), classical swine (CS), and Eurasian avian‐like (EA) swine lineages. Farm‐level risk factors were identified using a zero‐inflated negative binomial model. Results We found a maximal seroprevalence of H1N1pdm of 55·6% [95% CI: 38·1–72·1] in the slaughterhouse at the end of December 2009, 2 weeks after the peak of reported human fatalities with H1N1pdm. Farm‐level seroprevalence was 29% [95% CI: 23·2–35·7]. In seropositive farms, within‐herd seroprevalence ranged from 10 to 100%. We identified an increased risk of infection for farms that specialized in fattening and a decreased risk of infection in farms hiring external swine workers. Conclusions Our findings suggest extensive reverse‐zoonotic transmission from humans to pigs with subsequent onward transmission within pig herds.     

Experimental inoculation of pigs with pandemic H1N1 2009 virus and HI cross-reactivity with contemporary swine influenza virus antisera

Please cite this paper as: Vincent et al. (2010) Experimental inoculation of pigs with pandemic H1N1 2009 virus and HI cross-reactivity with contemporary swine influenza virus antisera. Influenza and Other Respiratory Viruses 4(2), 53–60 Background A novel A/H1N1 was identified in the human population in North America in April 2009. The gene constellation of the virus was a combination from swine influenza A viruses (SIV) of North American and Eurasian lineages that had never before been identified in swine or other species. Objectives The objectives were to (i) evaluate the clinical response of swine following experimental inoculation with pandemic H1N1 2009; (ii) assess serologic cross-reactivity between H1N1 2009 and contemporary SIV antisera; and (iii) develop a molecular assay to differentiate North American-lineage SIV from H1N1 2009. Methods Experiment 1: Weaned pigs were experimentally infected with A/California/04/2009 (H1N1). Experiment 2: The cross-reactivity of a panel of US SIV H1N1 or H1N2 antisera with three isolates of pandemic A/H1N1 was evaluated. Experiment 3: A polymerase chain reaction (PCR)-based diagnostic test was developed and validated on samples from experimentally infected pigs. Results and Conclusions In experiment 1, all inoculated pigs demonstrated clinical signs and lesions similar to those induced by endemic SIV. Viable virus and antigen were only detected in the respiratory tract. In experiment 2, serologic cross-reactivity was limited against H1N1 2009 isolates, notably among virus antisera from the same HA phylogenetic cluster. The limited cross-reactivity suggests North American pigs may not be fully protected against H1N1 2009 from previous exposure or vaccination and novel tests are needed to rapidly diagnose the introduction of H1N1 2009. In experiment 3, an RT–PCR test that discriminates between H1N1 2009 and endemic North American SIV was developed and validated on clinical samples.     

Liver involvement in severe human influenza A H1N1

Influenza A is a disease caused by a RNA virus, member of the orthomyxoviridae family. The influenza infection is characterized primarily by pulmonary affection that may advance to an acute pulmonary respiratory failure course. Hepatic involvement is not frequent and accounts for < 3% of all cases. We describe two patients with acute Influenza A H1N1 infection who developed hepatic involvement. Needle core liver biopsy of one of the patients revealed only micro and macrovesicular steatosis.     

Prior infection with classical swine H1N1 influenza viruses is associated with protective immunity to the 2009 pandemic H1N1 virus

Please cite this paper as: Kash et al. (2010) Prior infection with classical swine H1N1 influenza viruses is associated with protective immunity to the 2009 pandemic H1N1 virus. Influenza and Other Respiratory Viruses 4(3), 121–127. Background  The 2009 H1N1 pandemic emerged even though seasonal H1N1 viruses have circulated for decades. Epidemio‐logical evidence suggested that the current seasonal vaccine did not offer significant protection from the novel pandemic, and that people over the age of 50 might were less susceptible to infection. Objectives  In a mouse challenge study with the 2009 pandemic H1N1 virus, we evaluated protective immune responses elicited by prior infection with human and swine influenza A viruses. Results  Mice infected with A/Mexico/4108/2009 (Mex09) showed significant weight loss and 40% mortality. Prior infection with a 1976 classical swine H1N1 virus resulted in complete protection from Mex09 challenge. Prior infection with either a 2009 or a 1940 seasonal H1N1 influenza virus provided partial protection and a >100‐fold reduction in viral lung titers at day 4 post‐infection. Conclusions  These findings indicate that in experimental animals recently induced immunity to 1918‐derived H1N1 seasonal influenza viruses, and to a 1976 swine influenza virus, afford a degree of protection against the 2009 pandemic virus. Implications of these findings are discussed in the context of accumulating data suggesting partial protection of older persons during the 2009 pandemic.     

Hospitalizations from pandemic Influenza [A(H1N1)pdm09] infections among type 1 and 2 diabetes patients in Spain

Objectives To describe and analyze the clinical characteristics and outcomes for all patients with diabetes who were hospitalized with laboratory‐confirmed A(H1N1)pdm09 infections in Spain during 2009. Methods Observational retrospective study using data collected by the Spanish National Hospital Discharge Database. We selected all admissions with diagnosis ICD‐9‐CM code 488·1 [A(H1N1)pdm09]. Discharges were grouped as follows: no diabetes, Type1 and Type 2 diabetes. Underlying medical conditions and risk factors included all those that constitute an indication for annual influenza vaccination, pregnancy, and obesity. The outcome variables analyzed were in‐hospital case fatality risk, length of hospital stay, and costs. Results The total number of persons hospitalized with A(H1N1)pdm09 was 11 499. Of those, 97 suffered Type 1 and 936 Type 2, giving an overall prevalence of diabetes of 9%. The most common underlying medical condition among Type 2 subjects was obesity (26·8%), and for Type 1 renal disease (10·3%). In‐hospital mortality was 2·1% among Type 1 patients, 3·8% among Type 2 patients, and 2·3% among non‐diabetics; after multivariate analysis, diabetes was not a factor independently associated with dying during hospitalization for A(H1N1)pdm09. Independent factors increasing the risk of death among diabetic patients included age (OR 1·03; 95% CI1·01–1·05), hematological disorders (OR 3·49; 95% CI, 1·46–8·37), and obesity (OR 1·88; 95% CI1·07–3·92). Conclusions Among individuals hospitalized in Spain with A(H1N1)pdm09 infections, the age‐specific prevalence of diabetes was higher than the general population in most age groups. The results of multivariate analysis suggest that possibly concomitant conditions such as obesity increase the risk of dying from the infection, but not diabetes itself.