Nosocomial pandemic (H1N1) 2009, United Kingdom, 2009-2010

To determine clinical characteristics of patients hospitalized in the United Kingdom with pandemic (H1N1) 2009, we studied 1,520 patients in 75 National Health Service hospitals. We characterized patients who acquired influenza nosocomially during the pandemic (H1N1) 2009 outbreak. Of 30 patients, 12 (80%) of 15 adults and 14 (93%) of 15 children had serious underlying illnesses. Only 12 (57%) of 21 patients who received antiviral therapy did so within 48 hours after symptom onset, but 53% needed escalated care or mechanical ventilation; 8 (27%) of 30 died. Despite national guidelines and standardized infection control procedures, nosocomial transmission remains a problem when influenza is prevalent. Health care workers should be routinely offered influenza vaccine, and vaccination should be prioritized for all patients at high risk. Staff should remain alert to the possibility of influenza in patients with complex clinical problems and be ready to institute antiviral therapy while awaiting diagnosis during influenza outbreaks.     

H275Y mutant pandemic (H1N1) 2009 virus in immunocompromised patients

Most oseltamivir-resistant pandemic (H1N1) 2009 viruses have been isolated from immunocompromised patients. To describe the clinical features, treatment, outcomes, and virologic data associated with infection from pandemic (H1N1) 2009 virus with H275Y mutation in immunocompromised patients, we retrospectively identified 49 hematology-oncology patients infected with pandemic (H1N1) 2009 virus. Samples from 33 of those patients were tested for H275Y genotype by allele-specific real-time PCR. Of the 8 patients in whom H275Y mutations was identified, 1 had severe pneumonia; 3 had mild pneumonia with prolonged virus shedding; and 4 had upper respiratory tract infection, of whom 3 had prolonged virus shedding. All patients had received oseltamivir before the H275Y mutation was detected; 1 had received antiviral prophylaxis. Three patients excreted resistant virus for >60 days. Emergence of oseltamivir resistance is frequent in immunocompromised patients infected with pandemic (H1N1) 2009 virus and can be associated with a wide range of clinical disease and viral kinetics.     

Oseltamivir Resistance in Adult Oncology and Hematology Patients Infected with Pandemic (H1N1) 2009 Virus, Australia

We describe laboratory-confirmed influenza A pandemic (H1N1) 2009 in 17 hospitalized recipients of a hematopoietic stem cell transplant (HSCT) (8 allogeneic) and in 15 patients with malignancy treated at 6 Australian tertiary centers during winter 2009. Ten (31.3%) patients were admitted to intensive care, and 9 of them were HSCT recipients. All recipients of allogeneic HSCT with infection <100 days posttransplantation or severe graft-versus-host disease were admitted to an intensive care unit. In-hospital mortality rate was 21.9% (7/32). The H275Y neuraminidase mutation, which confers oseltamivir resistance developed in 4 of 7 patients with PCR positive for influenza after >4 days of oseltamivir therapy. Three of these 4 patients were critically ill. Oseltamivir resistance in 4 (13.3%) of 30 patients who were administered oseltamivir highlights the need for ongoing surveillance of such resistance and further research on optimal antiviral therapy in the immunocompromised.     

Oseltamivir-resistant pandemic (H1N1) 2009 virus infection in England and Scotland, 2009-2010

Oseltamivir has been widely used for pandemic (H1N1) 2009 virus infection, and by April 30, 2010, a total of 285 resistant cases were reported worldwide, including 45 in the United Kingdom. To determine risk factors for emergence of oseltamivir resistance and severe infection, a case-control study was conducted in the United Kingdom. Study participants were hospitalized in England or Scotland during January 4, 2009-April 30, 2010. Controls had confirmed oseltamivir-sensitive pandemic (H1N1) 2009 virus infections, and case-patients had confirmed oseltamivir-resistant infections. Of 28 case-patients with available information, 21 (75%) were immunocompromised; 31 of 33 case-patients (94%) received antiviral drugs before a sample was obtained. After adjusting for confounders, case-patients remained significantly more likely than controls to be immunocompromised and at higher risk for showing development of respiratory complications. Selective drug pressure likely explains the development of oseltamivir resistance, especially among immunocompromised patients. Monitoring of antiviral resistance is strongly recommended in this group.     

Influenza in Refugees on the Thailand�CMyanmar Border, May�COctober 2009

We describe the epidemiology of influenza virus infections in refugees in a camp in rural Southeast Asia during May–October 2009, the first 6 months after identification of pandemic (H1N1) 2009 in Thailand. Influenza A viruses were detected in 20% of patients who had influenza-like illness and in 23% of those who had clinical pneumonia. Seasonal influenza A (H1N1) was the predominant virus circulating during weeks 26–33 (June 25–August 29) and was subsequently replaced by the pandemic strain. A review of passive surveillance for acute respiratory infection did not show an increase in acute respiratory tract infection incidence associated with the arrival of pandemic (H1N1) 2009 in the camp.     

Serologic survey of pandemic influenza A (H1N1 2009) in Beijing, China

Objective

To examine the frequency and distribution of antibodies against pandemic influenza A (H1N1 2009) [H1N1] in populations in Beijing and elucidate influencing factors.

Methods

In January 2010, a randomized serologic survey of pandemic influenza A (H1N1 2009) was carried out. Six districts that were randomly selected with a total of 4601 participants involved in the survey have their antibody level tested by hemagglutination inhibition assay.

Results

Among the 4601 participants, the overall seropositive rate for pandemic influenza A (H1N1 2009) antibodies was 31.7%. The seropositivity prevalence in participants who received the pandemic H1N1 vaccination was 60.9%. Only 53.1% of the pandemic influenza A (H1N1 2009) seropositive individuals who had not received the vaccination experienced respiratory tract infection symptoms. Multivariate logistic regression revealed that factors such as age, occupation, dwelling type, whether the participant's family included students in school, and the vaccination history with pandemic influenza A (H1N1 2009) were associated with antibody titers (p < 0.05).

Conclusions

Our data indicated that almost 30.0% of the residents had appropriate antibody titers against pandemic influenza A (H1N1 2009) in Beijing, and these titers may provide an immune barrier.     

Deaths associated with pandemic (H1N1) 2009 among children, Japan, 2009-2010

To clarify the cause of deaths associated with pandemic (H1N1) 2009 among children in Japan, we retrospectively studied 41 patients <20 years of age who had died of pandemic (H1N1) 2009 through March 31, 2010. Data were collected through interviews with attending physicians and chart reviews. Median age of patients was 59 months; one third had a preexisting condition. Cause of death was categorized as unexpected cardiopulmonary arrest for 15 patients, encephalopathy for 15, and respiratory failure for 6. Preexisting respiratory or neurologic disorders were more frequent in patients with respiratory failure and less frequent in patients with unexpected cardiopulmonary arrest. The leading causes of death among children with pandemic (H1N1) 2009 in Japan were encephalopathy and unexpected cardiopulmonary arrest. Deaths associated with respiratory failure were infrequent and occurred primarily among children with preexisting conditions. Vaccine use and public education are necessary for reducing influenza-associated illness and death.     

Pandemic (H1N1) 2009 risk for frontline health care workers

To determine whether frontline health care workers (HCWs) are at greater risk for contracting pandemic (H1N1) 2009 than nonclinical staff, we conducted a study of 231 HCWs and 215 controls. Overall, 79 (17.7%) of 446 had a positive antibody titer by hemagglutination inhibition, with 46 (19.9%) of 231 HCWs and 33 (15.3%) of 215 controls positive (OR 1.37, 95% confidence interval 0.84-2.22). Of 87 participants who provided a second serum sample, 1 showed a 4-fold rise in antibody titer; of 45 patients who had a nose swab sample taken during a respiratory illness, 7 had positive results. Higher numbers of children in a participant's family and working in an intensive care unit were risk factors for infection; increasing age, working at hospital 2, and wearing gloves were protective factors. This highly exposed group of frontline HCWs was no more likely to contract pandemic (H1N1) 2009 influenza infection than nonclinical staff, which suggests that personal protective measures were adequate in preventing transmission.     

Pandemic whole-virion,Vero-cell-derived,adjuvant-free influenza A H1N1 vaccine in patients with solid tumors and hematologic malignancies receiving concurrent anticancer treatment: Immunogenicity,tolerability, and acceptability during the pandemic situation

Patients with malignancies are considered to be at increased risk of acquiring influenza. Because of higher complication and case fatality rates, preventive measures such as vaccination are of great interest. The objective of this study was to assess the acceptability, tolerability and immunogenicity of an adjuvant-free whole-virion pandemic influenza A (H1N1) vaccine in cancer patients with ongoing anticancer treatment during a ‘pandemic situation’. Adult patients with hematologic malignancies or solid tumors and concurrent cytotoxic, targeted, and/or hormone therapy were recruited during the influenza A (H1N1) pandemic in 2009/2010 and were offered free vaccine. Antibody titers were measured using virus-specific hemagglutination inhibition assay and ELISA. Among 285 patients with solid tumors who were offered vaccination during their therapy, 260 (91.2%) declined and 25 (8.8%) accepted. Seventeen patients with hematologic malignancies were also vaccinated during therapy; 23 healthy individuals served as a control group. When measured using hemagglutination-inhibition assays, rates of seroprotection, seroconversion, and geometric mean titer ratios after the second vaccination were 96%, 70%, and 4.1 respectively among the healthy individuals, 90%, 52%, and 4.3 among patients with solid tumors, and 67%, 13%, and 1.5 among patients with hematologic malignancies during therapy (P < 0.05). When measured using ELISA, seropositivity differed significantly among the three groups after the second vaccination: healthy individuals 74%, patients with solid tumors 57%, those with hematologic malignancies 13% (P < 0.001). The vaccine was well tolerated. Our results demonstrate a low uptake of the well tolerated adjuvant-free influenza A (H1N1) vaccine by cancer patients receiving anticancer treatment during the pandemic of 2009/2010. Among the vaccinated patients, the immune response was weaker than that in healthy individuals. The immune response in patients with hematological malignancies was low. Two doses of vaccine are needed in these immunosuppressed patients.     

Pandemic influenza in Canadian children: A summary of hospitalized pediatric cases

A total of 324 pandemic H1N1 cases were reported to the Immunization Monitoring Program, Active from May 1, 2009 to August 31, 2009. As of August 31, 2009, case details were available for 73% (n = 235) of these cases. The median age was 4.8 years and 69% of children were older than 2 years of age. In total, 95 (40%) of children were previously healthy. The proportion with an underlying health condition increased with age. Close to 50% of children received antiviral medication. Two children died from the infection. The pediatric risk groups affected and course of disease caused by pandemic H1N1 appear similar to seasonal influenza.     

The impact of climate on the prevalence of respiratory tract infections in early childhood in Lahore, Pakistan.

BACKGROUND: Respiratory tract infections are a major health problem in developing countries. The aim of this study was to analyse the impact of the climate on the prevalence of upper respiratory tract infection (URTI) and lower respiratory tract infection (LRTI) in four socioeconomically different groups in a developing country. METHODS: A prospective cohort study was conducted among children in four socioeconomically different groups in Lahore, Pakistan. Monthly observations were made on 1476 infants born during 1984-1987 and followed for 24 months. Prevalence of URTI and LRTI was analysed according to age, area of living, family size, time of birth, the season of the year and climate variables such as rain, temperature and humidity. RESULTS: Low monthly average minimum day temperature was associated with high prevalence of URTI and LRTI. For LRTI the impact of temperature was larger for boys, children living in larger families and children living in the poorer areas. This pattern was not seen for URTI. A peak in prevalence for LRTI was shown at 5-6 months of age for LRTI and at 10-12 months of age for URTI. CONCLUSIONS: Temperature is related to prevalence of URTI and LRTI in a developing society. The effect of temperature on health varies between different subgroups. These effects should be considered in planning health actions to prevent respiratory tract infections.     

La grippe maligne vue à la lumière du passé

The first influenza pandemic of the xxist century is due to a novel A (H1N1) strain. The infection, which affects younger patients than seasonal influenza, presents most often under a benign form. But it can rarely and rapidly evolve to pulmonary parenchymal involvement, independently of any bacterial superinfection or co-infection. It becomes a true viral pneumonia, which can evolve to acute respiratory distress syndrome (ARDS). This phenomenon was well described for the three xxth century pandemics, especially for the 1968–1969 one. These cases of “malignant flu” benefitted from the great breakthroughs in medical intensive care made in the previous 15 years. The specificity of these pandemic strains to infect lower respiratory tract is of immunological origin: only patients with little or no immunity to the virus can develop viral pneumonia and ARDS. This is why trivalent vaccination against seasonal flu appears to be somewhat protective against severe presentations of the disease. During winter 2009–2010, an inflow of flu-related ARDS cases is expected in French ICUs. Aggressive oxygenation techniques, high dose and prolonged antiviral treatment, and steroid adjunctive therapy, could be used, adding to the experience acquired during previous pandemics.     

江苏省苏州市2009--2010年甲型H1N1流感住院病例抗病毒药物使用情况调查

目的 了解甲型H1N1流感大流行期间流感住院病例抗病毒药物使用情况及存在的问题.方法 选择苏州市3家市级医院.查看2009年6月至2010年3月甲型H1N1流感大流行期间住院治疗的甲型H1N1流感病例的病历资料,了解抗病毒药物的使用情况及有关信息.结果 98%(222/226)的甲型H1N1流感住院病例在住院期间使用过抗病毒药物,其中92%(205/222)使用过神经氨酸酶抑制剂--奥司他韦,但仅18%是在发病后2 d内开始用药.未发现医院对住院甲型H1N1流感病例使用金刚烷胺、金刚乙胺等抗病毒药物.对医生进行访谈发现,就诊延迟、医生误诊、等待实验室检测与结果 反馈等因素影响奥司他韦的及时使用.结论 在甲型H1N1流感大流行期间,苏州市3家市级医院绝大多数住院病例使用了奥司他韦,但药物使用及时性差.需要开发甲型H1N1流感病毒的快速检测技术,提高医生的诊断水平,以缩短病例诊断时间,提高用药的时效性,改善这类抗病毒药物的使用效果.

Abstract：

Objective To explore the use of antiviral drugs in treating the hospitalized patients of novel influence A(H1N1)in Suzhou city during the 2009-2010 influenza pandemic,so as to make the proper use of antiviral drugs during influenza epidemics.Methods We selected 3municipal hospitals and reviewed the medieal records of hospimlized patients suffered from novel influence A(H1N1)during June 2009 to March 2010,to gather antiviral use and other related information.Results 98%(222/226)of the hospitalized patients received antiviral treatment.Among them,92%(205/222)were given the neuraminidase inhibitor oseitamivir.However,only 18% of the patients who received oseltamivir were given the treatment within 2 days after the onset of the illness.Amantadine and rimantadinc were not used for any of the hospitalized patients.Through interview on the physicians,we identified that delay in seeing care,misdiagnosis,delay in laboratory diagnosis were factors affecting the timely use of oseltamivir.Conclusion The majority of the hospitalized patients suffered from novel influence A(H1N1)in the three municipal hospitals received oseltamivir treatment.However,in most occasions the drug was not used timely.Techniques of rapid detection and diagnosis for novel influenza A(H1N1)virus should be developed,and the diagnostic capabilities of the physicians improved,to increase the effectiveness of these antiviral drugs.     

Respiratory Infection in Institutions during Early Stages of Pandemic (H1N1) 2009, Canada

Outbreaks of respiratory infection in institutions in Ontario, Canada were studied from April 20 to June 12, 2009, during the early stages of the emergence of influenza A pandemic (H1N1) 2009. Despite widespread presence of influenza in the general population, only 2 of 83 outbreaks evaluated by molecular methods were associated with pandemic (H1N1) 2009.     

Pandemic A/H1N1/2009 influenza in a paediatric haematology and oncology unit: successful management of a sudden outbreak

Viral respiratory infections are potentially life-threatening among children treated for cancer. We report a nosocomial outbreak of six cases of pandemic influenza A/H1N1/2009 on a paediatric haematology and oncology ward. Three patients developed pneumonia and two of them sustained haemodynamic collapse. The source was probably a relative of the first infected patient. The outbreak was probably spread by cross-infection between patients during communal activities. A few days' delay in identifying the outbreak promoted spread of the influenza. Infection control measures included the use of oral oseltamivir treatment for all hospitalised patients, isolation of the infected patients, strict personal protective controls and a restriction on visitors. No new cases occurred after implementation of these containment measures. At the time when the outbreak was identified, all the patients were already isolated for other reasons. We conclude that A/H1N1/2009 influenza may spread rapidly and cause severe infection in paediatric cancer patients but can be efficiently contained. Identification of isolated or clustered cases should lead to the rapid implementation of appropriate infection control measures.     

Severe Pneumonia Associated with Pandemic (H1N1) 2009 Outbreak, San Luis Potos��, Mexico

We describe the clinical characteristics and outcomes of adults hospitalized with pneumonia during the pandemic (H1N1) 2009 outbreak. Patients admitted to a general hospital in San Luis Potosí, Mexico, from April 10 through May 11, 2009, suspected to have influenza virus–associated pneumonia were evaluated. We identified 50 patients with suspected influenza pneumonia; the presence of influenza virus was confirmed in 18: 11 with pandemic (H1N1) 2009 virus, 5 with unsubtypeable influenza A virus, 1 with seasonal influenza A virus (H3N2), and 1 in whom assay results for seasonal and pandemic (H1N1) 2009 viruses were positive. Eighteen patients were treated in the intensive care unit, and 10 died. During the pandemic (H1N1) 2009 outbreak, severe pneumonia developed in young adults who had no identifiable risk factors; early diagnosis and treatment of influenza virus infections may have a determinant role in outcome.     

Adult intensive-care patients with 2009 pandemic influenza A(H1N1) infection

In France, the surveillance of hospitalized cases of pandemic influenza was implemented in July 2009 and restricted to intensive-care unit (ICU) patients in November. We described the characteristics of the 1065 adult patients admitted to ICUs and analysed risk factors for severe outcome (mechanical ventilation or death). Eighty-seven percent of cases were aged 15-64 years. The case-fatality ratio was 20%. The risk for severe outcome increased with age and obesity while this association was negative for chronic respiratory disease. Late antiviral therapy was associated with a severe outcome in ICU patients with risk factors (adjusted OR 2·0, 95% CI 1·4-3·0). This study confirms the considerable contribution of young adults to A(H1N1) 2009 mortality. It shows the role of obesity as an independent risk factor for severe disease, and of early antiviral therapy as a protective factor, at least in patients with risk factors.     

Severe cases of pandemic (H1N1) 2009 in children, Germany

In a hospital-based observational study in Germany, we investigated children admitted to pediatric intensive care units and deaths caused by confirmed pandemic (H1N1) 2009 to identify risk factors and outcomes in critically ill children. Ninety-three children were eligible for our study, including 9 with hospital-acquired infections. Seventy-five percent had underlying chronic medical conditions; neurodevelopmental disorders were most prevalent (57%). The proportion of patients having ≥1 risk factor increased with age in years (odds ratio 1.21, p = 0.007). Of 15 deaths, 11 occurred in a pediatric intensive care unit (case-fatality rate 12%, 95% confidence interval 6%-21%). Only 9% of the children had been vaccinated against pandemic (H1N1) 2009; all survived. Our results stress the role of underlying risk factors, especially neurodevelopmental disorders, and the need for improving preventive measures to reduce severe disease and adverse outcomes of pandemic (H1N1) 2009 in children.