Factors associated with increased vaccination in 2009 H1N1 school-located influenza vaccination programs

In the United States, school-located influenza vaccination (SLIV) programs have increased significantly in recent years. In June 2010, the Office of Inspector General issued a report regarding 38 elementary school H1N1 SLIV programs conducted in 6 localities in November/December 2009. By locality, there was a mean of 14 to 46 first doses of vaccine administered per 100 students. The locality that conducted programs in early November had a higher uptake rate than localities with later programs (46 vs 21 per 100 students; p < 0.01). Among localities with programs in mid- to late-November, the locality with programs after school hours had a lower uptake rate than the two localities with programs during school hours (16 vs. 28, p = 0.05 and 16 vs. 30, p < 0.01, respectively). These data suggest that future SLIV programs may achieve higher uptake rates if conducted during school hours with advance parental consent and when parental demand is highest.     

上海地区在校中学生接种甲型H1N1流感疫苗前后抗体水平监测分析

 目的  了解上海地区在校中学生接种甲型H1N1流感疫苗前后的抗体水平;观察甲型H1N1流感疫苗对该人群的免疫保护作用。 方法    应用常规微量血凝抑制试验（micro-hemagglutination inhibition test, HIT）对上海地区在校中学生分3个时间段进行甲型H1N1流感病毒抗体的血清学监测,3个时间段的抗体阳性率比较采用Pearson χ2 检验进行分析。 结果  2009年甲型H1N1流感流行前上海地区在校中学生的血清抗体阳性率仅为1.3%。经过一段时间流行后,血清抗体阳性率升至8.5%。接种甲型H1N1流感疫苗后,血清抗体阳性率升至87.3%。经Pearson χ² 检验分析,3个时间段在校中学生的血清甲型H1N1流感抗体阳性率差异有统计学意义（χ²=243.7,P<0.05）。 结论  在甲型H1N1流感流行前,上海地区在校中学生对其几乎没有免疫力,接种甲型H1N1流感疫苗能为该人群提供较好的免疫保护作用。     

甲型H1N1流感儿童发生呼吸衰竭的危险因素分析

目的探讨儿童甲型H1N1流感患者发生呼吸衰竭（acute respiratory failure,ARF）的危险因素,为针对性预防其发生提供临床依据。方法对2009年9月至2010年1月我院住院51例甲型H1N1流感儿童的资料进行回顾性分析。结果51例儿童甲型H1N1流感患儿,5例发生呼吸衰竭,发生率为9．80％,多元回归分析最近有呼吸道感染或使用免疫抑制剂、中性粒细胞计数〉70％,具有统计学意义（P〈0．05）,均为独立的危险因素。结论甲型H1N1流感儿童必须预防或积极治疗其合并的细菌感染,以防呼吸衰竭的发生。     

天津地区儿童甲型H1N1流感病例报告

目的 总结天津市7例儿童散发甲型H1N1流感病例的临床特点,为本病的诊治预防提供临床经验,评估预后。方法 回顾性分析2009年6月9日至2009年9月21日我院收治的儿童甲型H1N1流感确诊病例的临床资料、防护措施,并结合文献进行复习。结果 7例患儿中男4例,女3例,年龄1.5 ～13 岁,中位年龄6岁。6例输入性病例,1例二代病例。主要症状均有发热、咳嗽,5例高热,3例伴咳痰;其他症状有乏力、头晕、头痛、流涕、喷嚏、咽痛咽痒。2例白细胞降低;2例合并感染白细胞升高;3例正常。5例胸片正常,1例纹理紊乱,1例双肺渗出性片状影。7例均于起病2天内经口咽拭子PCR(RT-PCR) 甲型H1N1流感病毒核酸检测阳性,在病程第6—9天阴转。6例奥司他韦治疗5天, 1例病毒合剂治疗5天。平均住院8天,均症状消失治愈出院。在非直接暴露的情况下家属和医护均未被感染。 结论 7例患儿主要症状为发热、咳嗽,平均病程9.1天,预后好,本病可控可防可治。     

96例儿童甲型H1N1流感患者的临床分析

目的探讨儿童甲型H1N1流感的临床特征及疗效。方法回顾性分析我院2014年1月~2016年11月收治的儿童甲型H1N1流感患者96例,对患儿年龄、实验室检查、临床症状及病程转归进行重点分析。结果儿童甲型H1N1流感患者以婴幼儿多见(85.4%),临床表现以发热、咳嗽及流涕等呼吸道表现为主,外周血白细胞总数正常或减低,甲型H1N1流感病毒检测阳性;96例患儿均治愈出院,平均住院时间为(7.0±1.2)d;早期口服奥司他韦治疗组较晚期口服治疗组住院时间缩短,两组比较差异有统计学意义(P<0.05)。结论在甲型流感流行季节,对于外周血白细胞不高的发热患者,早期口服奥司他韦治疗可以减轻临床症状,缩短病程,避免呼吸衰竭等严重并发症的发生。     

Detection of respiratory viruses in the 2009 winter season in Rome: 2009 influenza A (H1N1) complications in children and concomitant type 1 diabetes onset

We investigated clinical characteristics and complications, particularly type 1 diabetes onset, in children hospitalized for 2009 pandemic influenza A (H1N1) virus and compared number of consultations, rate of hospitalization and virus identification in children hospitalized for acute respiratory symptoms (ARS) during the winter season 2009-2010 and 2004-2005. Patients were tested for 2009 H1N1 virus and 14 respiratory viruses on pharyngeal brush/nasal aspirates, using a RT-PCR or nested PCR assays. Consultations and hospitalizations were extracted from operative system GIPSE. The total number of consultations increased by 12%, consultation rate for ARS by 13% and number of hospitalizations by 56% from 2004-2005 to 2009-2010. In 2004-2005, Influenza A virus was identified in only 7 percent of hospitalized children, while in 2009-2010 the 2009 H1N1 virus was identified in 21%. Three children attending the hospital for ARS and 2009 H1N1 infection had ketoacidosis as the onset manifestation of type 1 diabetes. By comparing the number of new diabetes diagnoses among the two winter seasons, we found a higher number of new diagnoses in October 2009-January 2010 than in the same period in 2004-2005 (19 vs 10). Six children (13%), all presenting with pre-existing diseases, were admitted to the pediatric intensive care unit. No children died. The outbreak of this novel virus has increased pediatric consultation rates and hospitalizations compared with previous winters without causing deaths. The children at highest risk for severe infection are those with comorbidities. The 2009 H1N1 virus seems in some way involved in the pathogenesis of type 1 diabetes.     

湘西地区甲型H1N1流感危重患儿4例临床特点分析

目的探讨湘西自治州少数民族地区甲型H1N1流感危重患儿临床特点及诊疗体会。方法回顾性分析资料完整的本院儿科住院4例甲型H1N1流感危重患儿临床表现、实验室检查及影像学资料。结果 4例患儿早期无特异性表现,均为流感样症状。3例发热,1例病初体温未测,4例均咳嗽,少量痰液,病情加重可出现咳嗽加重,均有呼吸困难,无腹泻呕吐,2例3d未排大便,伴腹胀;随着病情进展都有多脏器功能不全,其中以肺脏受累最为突出。实验室检查：白细胞计数正常、降低或升高,多有肝肾功能异常。X线胸片提示双肺均有广泛受损害,表现为大片状高密度影。结论甲型H1N1流感危重患儿病情凶险,进展迅速,病死率高。因此,为了降低发病率,特别是降低危重症发病率,必须加强小于5岁的农村儿童甲型H1N1流感疫苗接种及防控工作,同时注重针对合并营养性缺铁性贫血儿童的早期治疗。早发现,早诊断,早期综合治疗,是降低甲型H1N1流感危重症病死率的关键。     

南京地区儿童甲型H1N1流感(重症)61例临床分析

目的 探讨儿童甲型H1N1流感(重症)的临床表现、诊断与治疗.方法 对61例儿童甲型H1N1流感(重症)的临床表现和实验室资料进行回顾分析.结果 61例甲流患儿均为本地流行病例,合并有肺炎者52例,支气管炎6例.最常见的症状是发热58例(95.1%);咳嗽52例(85.2%);喘息3例(0.4%);实验室检查显示白细胞...     

贵州省新型甲型HIN1(2009)流感病毒HA-1基因分析

目的 建立并完善贵州省新型甲型H1N1流感病毒基因分析检测技术平台,了解贵州省新型甲型H1N1(2009)流感病毒HA1片断与WHO公布的流行株有否发生变异.方法 收集16株新型甲型H1N1流感病毒毒株,提取病毒核酸RNA,通过RT-PCR扩增HA1片断,用电泳观察PCR产物目的条带大小,经过纯化、测序,用Biodeit、MEGA4相关软件进行序列比对,同源性及差异性分析,构建系统发育树.结果 贵州省(2009)代表株与中俄代表株A/Habarovak/01/2009 (H1N1)和墨西哥第一株甲型H1N1流感A/Mexio City/001/2009(H1N1)同属一个谱系,亲缘关系较近,同源性在93.2％～95.8％之间.结论 贵州省(2009)代表株与WHO公布的流行株在核苷酸水平上有一定程度的变异.     

Pandemic influenza vaccination coverage in children with type 1 diabetes: analysis from seven Italian centers

The pandemic influenza vaccination coverage in children with type 1 diabetes has been analysed. 1461 charts have been reviewed (788 M and 673 F, ages 13.0±4.1 yrs, disease duration 6.0±4.8 yrs, HbA1c 7.9±1.2%). Among them, 428 patients (29.3%) underwent A/H1N1 vaccination. A special effort is required to implement an increased immunization rate.     

Spontaneous Pneumomediastinum,Pneumopericardium and Pneumorrhachis as potential complications of 2009 pandemic influenza A (H1N1) virus infection in healthy children

We report on two cases of spontaneous pneumomediastinum and pneumopericardium, in one case associated with pneumorrhachis, occurring in two children suffering from the novel influenza H1N1 virus infection. At the admission both children presented with fever, violent dry cough, dyspnea and tachypnea. Radiological studies showed sizeable pneumomediastinum and pneumopericardium in both patients. One of the patients also a pneumorrachis. Children were initially treated by intravenous broad-spectrum antibiotics, antipyretics and a cough sedative. Oral Oseltamivir (60 mg twice daily for 5 days) was administered after the diagnosis of influenza A (H1N1) virus infection. Patients’ clinical condition quickly improved and children were discharged with a partial resolution of their radiological findings. Although these conditions are usually self-limiting and without respiratory or systemic consequences, their prompt recognition in children with H1N1 influenza virus infection is essential to establish fast and adequate therapy mainly related to the control of cough and the commencement of antiviral treatment.     

Oseltamivir in seasonal, avian H5N1 and pandemic 2009 A/H1N1 influenza: pharmacokinetic and pharmacodynamic characteristics

Oseltamivir is the ester-type prodrug of the neuraminidase inhibitor oseltamivir carboxylate. It has been shown to be an effective treatment for both seasonal influenza and the recent pandemic 2009 A/H1N1 influenza, reducing both the duration and severity of the illness. It is also effective when used preventively. This review aims to describe the current knowledge of the pharmacokinetic and pharmacodynamic characteristics of this agent, and to address the issue of possible therapeutic drug monitoring. According to the currently available literature, the pharmacokinetics of oseltamivir carboxylate after oral administration of oseltamivir are characterized by mean ± SD bioavailability of 79 ± 12%, apparent clearance of 25.3 ± 7.0 L/h, an elimination half-life of 7.4 ± 2.5 hours and an apparent terminal volume of distribution of 267 ± 122 L. A maximum plasma concentration of 342 ± 83 μg/L, a time to reach the maximum plasma concentration of 4.2 ± 1.1 hours, a trough plasma concentration of 168 ± 32 μg/L and an area under the plasma concentration-time curve from 0 to 24 hours of 6110 ± 1330 μg · h/L for a 75 mg twice-daily regimen were derived from literature data. The apparent clearance is highly correlated with renal function, hence the dosage needs to be adjusted in proportion to the glomerular filtration rate. Interpatient variability is moderate (28% in apparent clearance and 46% in the apparent central volume of distribution); there is no indication of significant erratic or limited absorption in given patient subgroups. The in vitro pharmacodynamics of oseltamivir carboxylate reveal wide variation in the concentration producing 50% inhibition of influenza A and B strains (range 0.17-44 μg/L). A formal correlation between systemic exposure to oseltamivir carboxylate and clinical antiviral activity or tolerance in influenza patients has not yet been demonstrated; thus no formal therapeutic or toxic range can be proposed. The pharmacokinetic parameters of oseltamivir carboxylate after oseltamivir administration (bioavailability, apparent clearance and the volume of distribution) are fairly predictable in healthy subjects, with little interpatient variability outside the effect of renal function in all patients and bodyweight in children. Thus oseltamivir carboxylate exposure can probably be controlled with sufficient accuracy by thorough dosage adjustment according to patient characteristics. However, there is a lack of clinical study data on naturally infected patients. In addition, the therapeutic margin of oseltamivir carboxylate is poorly defined. The usefulness of systematic therapeutic drug monitoring in patients therefore appears to be questionable; however, studies are still needed to extend the knowledge to particular subgroups of patients or dosage regimens.     

Oseltamivir-resistant influenza A(H1N1) 2009 virus in Greece during the post-pandemic 2010-2011 season

Information on the drug susceptibility of influenza epidemic strains is important for antiviral resistance monitoring. In Greece, the 2009-2010 pandemic waves were very mild and seroprevalence rates remained low after this influenza season, resulting in exclusive detection of the pandemic strain during the 2010-2011 influenza season. In the present study during the post-pandemic 2010-2011 season, 50 consecutive influenza A(H1N1) 2009 virus-positive samples from patients hospitalised in Greek hospitals were analysed for resistance to the neuraminidase inhibitor oseltamivir. All patients were hospitalised with severe influenza complications and had previously received oseltamivir. Influenza A(H1N1) 2009 virus detection and testing for oseltamivir resistance were performed with real-time PCR amplification assays. The H275Y substitution associated with resistance to oseltamivir was identified in two immunocompetent patients who received oseltamivir treatment for 3 days and 5 days, respectively. In both cases, patients were discharged in good condition despite development of resistance to antiviral treatment.     

Type 1 diabetes onset and pandemic influenza A (H1N1)

Type 1 diabetes (T1D) is a heterogeneous disorder characterized by destruction of pancreatic beta cells, culminating in loss of insulin secretion. Data from large epidemiologic studies worldwide indicate that during the last decades the incidence of T1D has increased significantly, reaching percentages of 2-5% annually. This increase suggests that there is a significant environmental contribution impacting the development of the disease, since genetic factors alone can hardly explain the rapid increase. Studies regarding T1D epidemiology in diverse populations aim to identify the disease causal factors and new targets for intervention. Viruses are one of the environmental factors implicated in the development of T1D in susceptible individuals. Recent studies suggest an association of T1D with H1N1 influenza. We would like to comment on this association and report our experience. Prospective studies are necessary to assess whether H1N1 infection is involved in T1D pathogenesis and provide directions on how to deal with viral infections in diabetes-susceptible individuals.     

Oseltamivir-resistant pandemic A(H1N1) 2009 influenza viruses detected through enhanced surveillance in the Netherlands, 2009–2010

Enhanced surveillance of infections due to the pandemic A(H1N1) influenza virus, which included monitoring for antiviral resistance, was carried out in the Netherlands from late April 2009 through late May 2010. More than 1100 instances of infection with the pandemic A(H1N1) influenza virus from 2009 and 2010 [A(H1N1) 2009] distributed across this period were analyzed. Of these, 19 cases of oseltamivir-resistant virus harboring the H275Y mutation in the neuraminidase (NA) were detected. The mean 50% inhibitory concentration (IC₅₀) levels for oseltamivir- and zanamivir-susceptible A(H1N1) 2009 viruses were 1.4-fold and 2-fold, respectively, lower than for the seasonal A(H1N1) influenza viruses from 2007/2008; for oseltamivir-resistant A(H1N1) 2009 virus the IC₅₀ was 2.9-fold lower. Eighteen of the 19 patients with oseltamivir-resistant virus showed prolonged shedding of the virus and developed resistance while on oseltamivir therapy. Sixteen of these 18 patients had an immunodeficiency, of whom 11 had a hematologic disorder. The two other patients had another underlying disease. Six of the patients who had an underlying disease died; of these, five had received cytostatic or immunosuppressive therapy. No indications for onward transmission of resistant viruses were found. This study showed that the main association for the emergence of cases of oseltamivir-resistant A(H1N1) 2009 virus was receiving antiviral therapy and having drug-induced immunosuppression or an hematologic disorder. Except for a single case of a resistant virus not linked to oseltamivir therapy, the absence of detection of resistant variants in community specimens and in specimens from contacts of cases with resistant virus suggested that the spread of resistant A(H1N1) 2009 virus was limited. Containment may have been the cumulative result of impaired NA function, successful isolation of the patients, and prophylactic measures to limit exposure.     

Review article: influenza A (H1N1) virus in patients with inflammatory bowel disease

Background  Infection with influenza A (H1N1) v (swine flu) has caused widespread anxiety, among patients who are potentially immunocompromised, such as those being treated for inflammatory bowel disease.
Aim  To provide guidance for physicians and their patients on the risk, prevention and management of influenza A (H1N1) v infection.
Methods  Medline was searched using the following key words: 'swine flu', 'immunosuppression', inflammatory bowel disease', 'recommendations', 'immunization', 'vaccination'. Organizations such as European Centre for Disease Prevention and Control, the Centers for Disease Control and Prevention and the World Health Organization were consulted for recent papers and recommendations regarding immunocompromised patients and influenza A (H1N1) v infection.
Results  Pandemic influenza A (H1N1) virus predominantly affects young patients. Those who are immunocompromised because of underlying disease or treatment are considered at higher risk of complications from influenza A (H1N1). They should be offered prevention (vaccination, postexposure prophylaxis) or treatment with antiviral drugs, if affected. Pneumococcal infection is a complication of influenza infection; therefore, pneumococcal vaccination appears advisable. Seasonal influenza vaccination is also recommended. Withdrawal of immunosuppressive treatment appears advisable during severe active infection if possible.
Conclusions  Pragmatic advice is the best that can be offered in the current circumstances because of paucity of evidence. Investigation into the impact of influenza A (H1N1) v infection in young people with chronic conditions is needed.