H1N1 novel influenza A in pregnant and immunocompromised patients

Obstetric Emergencies

Human gestation and birthing result in many deviations from usual physiology that are nonetheless normal to be seen. However, on occasion, certain complications in the obstetric patient can be life-threatening to both mother and fetus. Timely recognition of these disorders and allocation of the appropriate resources are especially important. These conditions often require an intensive care unit admission for closer monitoring and supportive care. They can affect an array of physiological systems and can lead to significant morbidity. Such complications are discussed in greater detail in this article.

The severity and risk factors for mortality in immunocompromised adult patients hospitalized with influenza-related pneumonia

Objective

To explore disease severity and risk factors for 30-day mortality of adult immunocompromised (IC) patients hospitalized with influenza-related pneumonia (Flu-p).

Method

A total of 122 IC and 1191 immunocompetent patients hospitalized with Flu-p from January 2012 to December 2018 were recruited retrospectively from five teaching hospitals in China.

Results

After controlling for confounders, multivariate logistic regression analysis showed that immunosuppression was associated with increased risks for invasive ventilation [odds ratio: (OR) 2.475, 95% confidence interval (CI): 1.511–4.053, p < 0.001], admittance to the intensive care unit (OR: 3.247, 95% CI 2.064–5.106, p < 0.001), and 30-day mortality (OR: 3.206, 95% CI 1.926–5.335, p < 0.001) in patients with Flu-p. Another multivariate logistic regression model revealed that baseline lymphocyte counts (OR: 0.993, 95% CI 0.990–0.996, p < 0.001), coinfection (OR: 5.450, 95% CI 1.638–18.167, p = 0.006), early neuraminidase inhibitor therapy (OR 0.401, 95% CI 0.127–0.878, p = 0.001), and systemic corticosteroid use at admission (OR: 6.414, 95% CI 1.348–30.512, p = 0.020) were independently related to 30-day mortality in IC patients with Flu-p. Based on analysis of the receiver operating characteristic curve (ROC), the optimal cutoff for lymphocyte counts was 0.6 × 10⁹/L [area under the ROC (AUROC) = 0.824, 95% CI 0.744—0.887], sensitivity: 97.8%, specificity: 73.7%].

Conclusions

IC conditions are associated with more severe outcomes in patients with Flu-p. The predictors for mortality that we identified may be valuable for the management of Flu-p among IC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00462-7.

Clinical and laboratory findings of patients with the possible diagnosis of influenza hospitalized in affiliated hospitals of Babol University of Medical Sciences, 2015-2016

The clinical and para clinical manifestations of influenza in various patients have range from an autoimmune disease to a life-threatening respiratory infection. In addition, the severity of the disease is influenced by factors such as demographic factors, underlying diseases, and immune response. Therefore, in this study, we evaluated the clinical, laboratory and epidemiological characteristics of patients with this type of influenza in Babol (north of Iran). This study was conducted as a descriptive cross-sectional study from October 2015 to March 2016. Subsequently, in this study, records of 123 patients with clinical signs of the influenza-like disease who have undergone the clinical sign in hospitals affiliated to Babol University of Medical Sciences were reviewed. Of 123 patients admitted to a possible diagnosis of influenza, 58 patients (47.2%) were PCR positive for H1N1, while seventy nine (64.2%) participants were women and 21 (17.1%) had diabetes or underlying lung disease. Most of the involved age groups were of individuals above the age of 50. These were followed by the 21-35 years-old. Fever (78%), cough (65.9%), shivering (58.5%) and myalgia (56.1%) were the most common clinical symptoms. Increased levels of transaminases (43.1%), leukocytosis (35.8%) and thrombocytopenia (34.2%) were as well reported in patients as the most frequently reported para clinical findings. In the present study, the most usual clinical symptoms were fever, cough, chill, and myalgia, while gastrointestinal symptoms were also noticeably observed in patients. In an experimental study, a significant number of patients showed leukocytosis and thrombocytopenia and increased transaminases.

Possible explanations for why some countries were harder hit by the pandemic influenza virus in 2009 - a global mortality impact modeling study

BACKGROUND

A global pandemic mortality study found prominent regional mortality variations in 2009 for Influenza A(H1N1)pdm09. Our study attempts to identify factors that explain why the pandemic mortality burden was high in some countries and low in others.

METHODS

As a starting point, we identified possible risk factors worth investigating for Influenza A(H1N1)pdm09 mortality through a targeted literature search. We then used a modeling procedure (data simulations and regression models) to identify factors that could explain differences in respiratory mortality due to Influenza A(H1N1)pdm09. We ran sixteen models to produce robust results and draw conclusions. In order to assess the role of each factor in explaining differences in excess pandemic mortality, we calculated the reduction in between country variance, which can be viewed as an effect-size for each factor.

RESULTS

The literature search identified 124 publications and 48 possible risk factors, of which we were able to identify 27 factors with appropriate global datasets. The modelling procedure indicated that age structure (explaining 40% of the mean between country variance), latitude (8%), influenza A and B viruses circulating during the pandemic (3-8%), influenza A and B viruses circulating during the preceding influenza season (2-6%), air pollution (pm10; 4%) and the prevalence of other infections (HIV and TB) (4-6%) were factors that explained differences in mortality around the world. Healthcare expenditure, levels of obesity, the distribution of antivirals, and air travel did not explain global pandemic mortality differences.

CONCLUSIONS

Our study found that countries with a large proportion of young persons had higher pandemic mortality rates in 2009. The co-circulation of influenza viruses during the pandemic and the circulation of influenza viruses during the preceding season were also associated with pandemic mortality rates. We found that real time assessments of 2009 pandemic mortality risk factors (e.g. obesity) probably led to a number of false positive findings.

Intravenous Immunoglobulin Protects Against Severe Pandemic Influenza Infection

Influenza is a highly contagious, acute, febrile respiratory infection that can have fatal consequences particularly in individuals with chronic illnesses. Sporadic reports suggest that intravenous immunoglobulin (IVIg) may be efficacious in the influenza setting. We investigated the potential of human IVIg to ameliorate influenza infection in ferrets exposed to either the pandemic H1N1/09 virus (pH1N1) or highly pathogenic avian influenza (H5N1). IVIg administered at the time of influenza virus exposure led to a significant reduction in lung viral load following pH1N1 challenge. In the lethal H5N1 model, the majority of animals given IVIg survived challenge in a dose dependent manner. Protection was also afforded by purified F(ab′)₂ but not Fc fragments derived from IVIg, supporting a specific antibody-mediated mechanism of protection. We conclude that pre-pandemic IVIg can modulate serious influenza infection-associated mortality and morbidity. IVIg could be useful prophylactically in the event of a pandemic to protect vulnerable population groups and in the critical care setting as a first stage intervention.

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Intravenous immunoglobulin (IVIg), prepared prior to a pandemic, prevents pandemic influenza disease in ferrets.

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IVIg effectively reduced viral levels of pandemic H1N1 influenza and prevented disease due to avian influenza H5N1.

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This work has implications for preventing and treating pandemic influenza infections with IVIg before a vaccine is available.

Influenza pandemics cause large numbers of infections and deaths. There is a lag between the identification of a pandemic and the development of vaccines. Future pandemics may be caused by influenza strains resistant to current anti-influenza drugs. New treatments are needed for future pandemic influenza outbreaks. We show that a readily available product (intravenous immunoglobuling – pooled antibodies from human donors) can prevent viral replication and disease caused by 2 strains of pandemic influenza viruses (“swine-flu” and “bird-flu”) in an appropriate animal model of influenza. This could form the basis of future treatments for severe influenza caused by pandemic strains.

Acute respiratory infections in children and adolescents with acute lymphoblastic leukemia

BACKGROUND

Knowledge regarding the incidence, clinical course, and impact of respiratory viral infections in children with acute lymphoblastic leukemia (ALL) is limited.

METHODS

A retrospective cohort of patients with newly diagnosed ALL who were treated on the Total Therapy XVI protocol at St Jude Children's Research Hospital between 2007 and 2011 was evaluated.

RESULTS

Of 223 children, 95 (43%) developed 133 episodes of viral acute respiratory illness (ARI) (incidence, 1.1 per 1000 patient-days). ARI without viral etiology was identified in 65 patients (29%) and no ARI was detected in 63 patients (28%). There were no significant associations noted between race, sex, age, or ALL risk group and the development of ARI. Children receiving induction chemotherapy were found to be at the highest risk of viral ARI (incidence, 2.3 per 1000 patient-days). Influenza virus was the most common virus (38%) followed by respiratory syncytial virus (33%). Of 133 episodes of viral ARI, 61% of patients were hospitalized, 26% experienced a complicated course, 80% had their chemotherapy delayed, and 0.7% of patients died. Twenty-four patients (18%) developed viral lower respiratory tract infections (LRTI), 5 of whom (21%) had complications. Patients with viral LRTI had a significantly lower nadir absolute lymphocyte count; were sicker at the time of presentation; and were more likely to have respiratory syncytial virus, to be hospitalized, and to have their chemotherapy delayed for longer compared with those with viral upper respiratory tract infections.

CONCLUSIONS

Despite the low incidence of viral ARI in children with ALL, the associated morbidity, mortality, and delay in chemotherapy remain clinically significant. Viral LRTI was especially associated with high morbidity requiring intensive care-level support. Cancer 2016;122:798-805. © 2015 American Cancer Society.

Do corticosteroids reduce the mortality of influenza A (H1N1) infection? A meta-analysis

Introduction

Corticosteroids are used empirically in influenza A (H1N1) treatment despite lack of clear evidence for effective treatment. This study aims to assess the efficacy of corticosteroids treatment for H1N1 infection.

Methods

Systematic review and meta-analysis were used to estimate the efficacy of corticosteroids for the prevention of mortality in H1N1 infection. Databases searched included MEDLINE, EMBASE, PubMed, Cochrane Central Register of Controlled Clinical Trials and so on, and bibliographies of retrieved articles, from April 2009 to October 2014. We included both cohort studies and case-control studies reported in English or Chinese that compared treatment effects between corticosteroids and non-corticosteroids therapy in inpatients with H1N1 virus infection. Cohort studies employed mortality as outcome, and case-control studies employed deaths as cases and survivors as controls; both were assessed in this meta-analysis.

Results

In total twenty-three eligible studies were included. Both cohort studies (nine studies, n = 1,405) and case-control studies (14 studies, n = 4,700) showed a similar trend toward increased mortality (cohort studies relative risk was 1.85 with 95% confidence interval (CI) 1.46 to 2.33; case-control studies odds ratio was 4.22 with 95% CI 3.10 to 5.76). The results from both subgroup analyses and sensitive analyses were consistent with each other, showing that steroid treatment is associated with mortality. However, considering the fact that corticosteroids were tend to be used in sickest case-patients and heterogeneity was observed between studies, we cannot make a solid conclusion.

Conclusions

Available evidence did not support the use of corticosteroids as standard care for patients with severe influenza. We conclude that further research is required.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0764-5) contains supplementary material, which is available to authorized users.

Detection of the influenza A(H1N1)pdm09 virus carrying the K-15E, P83S and Q293H mutations in patients who have undergone bone marrow transplant

The 2009 pandemic influenza A(H1N1)pdm09 virus emerged and caused considerable morbidity and mortality in the third world, especially in Brazil. Although circulating strains of A(H1N1)pdm09 are A/California/04/2009-like (CA-04-like) viruses, various studies have suggested that some mutations in the viral hemagglutinin (HA) may be associated with enhanced severity and fatality. This phenomenon is particularly challenging for immunocompromised individuals, such as those who have undergone bone marrow transplant (BMT), because they are more likely to display worse clinical outcomes to influenza infection than non-immunocompromised individuals. We studied the clinical and viral aspects of post-BMT patients with confirmed A(H1N1)pdm09 diagnosis in the largest cancer hospital in Brazil. We found a viral strain with K-15E, P83S and Q293H polymorphisms in the HA, which is presumably more virulent, in these individuals. Despite that, these patients showed only mild symptoms of infection. Our findings complement the discovery of mild cases of infection with the A(H1N1)pdm09 virus with the K-15E, P83S and Q293H mutations in Brazil and oppose other studies that have linked these changes with increased disease severity. These results could be important for a better comprehension of the impact of the pandemic influenza in the context of BMT.

Maintaining the momentum: key factors influencing acceptance of influenza vaccination among pregnant women following the H1N1 pandemic

This survey study compared pre- and post-pandemic knowledge, attitudes, beliefs, and intended behaviors of pregnant women regarding influenza vaccination (seasonal and/or pandemic) during pregnancy in order to determine key factors influencing their decision to adhere to influenza vaccine recommendations. Only 36% of 662 pre-pandemic respondents knew that influenza was more severe in pregnant women, compared to 62% of the 159 post-pandemic respondents. Of the pre-pandemic respondents, 41% agreed or strongly agreed that that it was safer to wait until after the first 3 months to receive the seasonal influenza vaccine, whereas 23% of the post-pandemic cohort agreed or strongly agreed; 32% of pre-pandemic participants compared to 11% of post-pandemic respondents felt it was best to avoid all vaccines while pregnant. Despite 61% of the pre-pandemic cohort stating that they would have the vaccine while pregnant if their doctor recommended it and 54% citing their doctor/nurse as their primary source of vaccine information, only 20% said their doctor discussed influenza vaccination during their pregnancy, compared to 77% of the post-pandemic respondents who reported having this conversation. Women whose doctors discussed influenza vaccine during pregnancy had higher overall knowledge scores (P<0.0001; P=0.005) and were more likely to believe the vaccine is safe in all stages of pregnancy (P<0.0001; P=0.001) than those whose doctors did not discuss influenza vaccination. The 2009 H1N1 pandemic experience appeared to change attitudes and behaviours of health care providers and their pregnant patients toward influenza vaccination.

Predictors of mortality and length of stay in hospitalized cases of 2009 influenza A (H1N1): Experiences of a tertiary care center

Aim:

To study the clinical characteristics and outcome of admitted patients of H1N1 (hemagglutinin -H neuraminidase -N) influenza in a tertiary level hospital, from Oct 2009 to Dec 2010.

Materials and Methods:

A retrospective analysis of 77 confirmed patients admitted in this unit with H1N1 infection.

Results:

Of the 77 patients studied, 33 (42.8%) were female. Mean age was 40.88 ± 13.45 years, majority (70.13%) being less than 50 years. Thirty eight (49.3%) patients had at least one co-morbidity, diabetes mellitus being the most common (n = 15, 19.5%). The most common presenting symptom was fever in 75 (97.4%) patients, cough in 67 (87%) and dyspnoea in 59 (76.6%) patients. At admission, mean PaO2/FiO2 ratio was 213.16 ± 132.75 mmHg (n = 60) while mean PaCO₂ was 40.14 ± 14.86 mmHg. One or more organ failure was present in 45 (58.4%) patients. Nineteen (24.60%) patients required invasive mechanical ventilation. Circulatory failure was observed in 10 (13%) patients while 2 patients required hemodialysis. Overall, 13% mortality (n = 10) was observed. PaCO₂ level at admission (OR 1.093; 95% confidence interval: 1.002-1.193; P = 0.044) and number of organ failure (OR 8.089; 95% confidence interval: 1.133-57.778; P = 0.037) were identified as independent risk- factors for mortality.

Conclusion:

Increased duration of dyspnoea prior to admission, pneumonia, low PaO₂/FiO₂ ratio at admission and 24 hours later, higher PaCO₂ values on admission, higher O₂ requirement, number of organ failures and use of corticosteroids and delay in specialized treatment were associated with a poorer outcome.

Report on influenza A and B viruses: their coinfection in a Saudi leukemia patient

PURPOSE

Influenza A and B viruses are the leading cause of respiratory infections in children worldwide, particularly in developing countries. There is a lack of data on coinfection of influenza A and B viruses circulating in Saudi Arabia. In this study, we aimed to identify the circulation of influenza viruses that contribute to respiratory tract infections in Saudi children.

METHODS

We collected 80 nasopharyngeal aspirates (NPAs) from hospitalized children with acute respiratory illness (ARI) at Riyadh during the period extended from October 2010 till April 2011. Samples were tested for the common respiratory viruses including influenza viruses by RT-PCR.

RESULTS

Overall, 6 samples were found positive for influenza A and/or B viruses. Among these positive clinical samples, only one collected sample from a female one-year-old immunocompromised child with leukemia showed a coinfection with influenza A and B viruses. In present study coinfection was confirmed by inoculation of the clinical specimen in specific pathogenfree embryonating chicken eggs and identification of the virus isolates by hemagglutination and one-step RT-PCR.

CONCLUSION

This study opens the scene for studying the role of influenza virus's coinfection in disease severity and virus evolution. Further studies are required to better understand the clinical importance of viral coinfection.

Influenza pandêmica A (H1N1) 2009: fatores de risco para o internamento

OBJETIVO: Avaliar os aspectos da influenza pandêmica A (H1N1) 2009 em pacientes hospitalizados a fim de identificar os fatores de risco para o internamento e, consequentemente, para o agravamento da doença. MÉTODOS: Estudo observacional e retrospectivo realizado entre março e dezembro de 2010. Os dados foram coletados a partir do Sistema Nacional de Agravos de Notificação do Ministério da Saúde. Foram incluídos somente os pacientes hospitalizados e não hospitalizados com confirmação laboratorial da infecção durante o período de estudo. As variáveis referentes às características demográficas e clínicas foram avaliadas estatisticamente a fim de comparar as taxas de internamento na presença ou na ausência desses fatores. Os fatores de risco foram identificados por regressão logística. RESULTADOS: Foram incluídos no estudo 4.740 pacientes com confirmação laboratorial da infecção. Desses, 1.911 foram internados, e 258 (13,5%) foram a óbito. Os fatores de risco para o internamento foram idade (faixa etária de 20 a 29 anos), etnia negra ou indígena, presença de algumas comorbidades (cardiopatias, pneumopatias, nefropatias, hemoglobinopatia, imunodepressão, diabetes, obesidade, puerpério e tabagismo), número alto de comorbidades associadas, e alguns sintomas (dispneia, diarreia, vômito, dor torácica, hemoptise, pneumonia e sibilos). Níveis maiores de escolaridade e uso precoce do oseltamivir foram relacionados a fatores de proteção. A hospitalização contribuiu para o aumento da sobrevida. CONCLUSÕES: O conhecimento das características epidemiológicas que podem estar associadas a internação, gravidade da doença e mortalidade podem ser úteis na adoção de medidas preventivas e no diagnóstico e tratamento precoce da doença, colaborando para a diminuição dos óbitos e da necessidade de hospitalização.

[Recommendations of the Infectious Diseases Work Group (GTEI) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) and the Infections in Critically Ill Patients Study Group (GEIPC) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) for the diagnosis and treatment of influenza A/H1N1 in seriously ill adults admitted to the Intensive Care Unit]

The diagnosis of influenza A/H1N1 is mainly clinical, particularly during peak or seasonal flu outbreaks. A diagnostic test should be performed in all patients with fever and flu symptoms that require hospitalization. The respiratory sample (nasal or pharyngeal exudate or deeper sample in intubated patients) should be obtained as soon as possible, with the immediate start of empirical antiviral treatment. Molecular methods based on nucleic acid amplification techniques (RT-PCR) are the gold standard for the diagnosis of influenza A/H1N1. Immunochromatographic methods have low sensitivity; a negative result therefore does not rule out active infection. Classical culture is slow and has low sensitivity. Direct immunofluorescence offers a sensitivity of 90%, but requires a sample of high quality. Indirect methods for detecting antibodies are only of epidemiological interest. Patients with A/H1N1 flu may have relative leukopenia and elevated serum levels of LDH, CPK and CRP, but none of these variables are independently associated to the prognosis. However, plasma LDH> 1500 IU/L, and the presence of thrombocytopenia <150 x 10(9)/L, could define a patient population at risk of suffering serious complications. Antiviral administration (oseltamivir) should start early (<48 h from the onset of symptoms), with a dose of 75 mg every 12h, and with a duration of at least 7 days or until clinical improvement is observed. Early antiviral administration is associated to improved survival in critically ill patients. New antiviral drugs, especially those formulated for intravenous administration, may be the best choice in future epidemics. Patients with a high suspicion of influenza A/H1N1 infection must continue with antiviral treatment, regardless of the negative results of initial tests, unless an alternative diagnosis can be established or clinical criteria suggest a low probability of influenza. In patients with influenza A/H1N1 pneumonia, empirical antibiotic therapy should be provided due to the possibility of bacterial coinfection. A beta-lactam plus a macrolide should be administered as soon as possible. The microbiological findings and clinical or laboratory test variables may decide withdrawal or not of antibiotic treatment. Pneumococcal vaccination is recommended as a preventive measure in the population at risk of suffering severe complications. Although the use of moderate- or low-dose corticosteroids has been proposed for the treatment of influenza A/H1N1 pneumonia, the existing scientific evidence is not sufficient to recommend the use of corticosteroids in these patients. The treatment of acute respiratory distress syndrome in patients with influenza A/H1N1 must be based on the use of a protective ventilatory strategy (tidal volume <10 ml / kg and plateau pressure <35 mmHg) and positive end-expiratory pressure set to high patient lung mechanics, combined with the use of prone ventilation, muscle relaxation and recruitment maneuvers. Noninvasive mechanical ventilation cannot be considered a technique of choice in patients with acute respiratory distress syndrome, though it may be useful in experienced centers and in cases of respiratory failure associated with chronic obstructive pulmonary disease exacerbation or heart failure. Extracorporeal membrane oxygenation is a rescue technique in refractory acute respiratory distress syndrome due to influenza A/H1N1 infection. The scientific evidence is weak, however, and extracorporeal membrane oxygenation is not the technique of choice. Extracorporeal membrane oxygenation will be advisable if all other options have failed to improve oxygenation. The centralization of extracorporeal membrane oxygenation in referral hospitals is recommended. Clinical findings show 50-60% survival rates in patients treated with this technique. Cardiovascular complications of influenza A/H1N1 are common. Such problems may appear due to the deterioration of pre-existing cardiomyopathy, myocarditis, ischemic heart disease and right ventricular dysfunction. Early diagnosis and adequate monitoring allow the start of effective treatment, and in severe cases help decide the use of circulatory support systems. Influenza vaccination is recommended for all patients at risk. This indication in turn could be extended to all subjects over 6 months of age, unless contraindicated. Children should receive two doses (one per month). Immunocompromised patients and the population at risk should receive one dose and another dose annually. The frequency of adverse effects of the vaccine against A/H1N1 flu is similar to that of seasonal flu. Chemoprophylaxis must always be considered a supplement to vaccination, and is indicated in people at high risk of complications, as well in healthcare personnel who have been exposed.

An outbreak of the 2009 influenza a (H1N1) virus in a children's hospital

Please cite this paper as: Bearden et al. (2012) An outbreak of the 2009 influenza a (H1N1) virus in a children’s hospital. Influenza and Other Respiratory Viruses 6(5), 374–379.

Context  Preventing nosocomial transmission of influenza is essential to reduce the morbidity and mortality associated with this infection. In October 2009, an outbreak of the 2009 influenza A (H1N1) virus occurred in a hematology ward of a children’s hospital over a 21‐day period and involved two patients and four healthcare workers.

Objective  To investigate nosocomial transmission of the 2009 influenza A (H1N1) virus in patients and healthcare workers.

Design, setting, and participants  An outbreak investigation was initiated in response to suspected nosocomial transmission of the 2009 influenza A (H1N1) virus during the peak of the 2009 pandemic. Cases were confirmed using a polymerase chain reaction (PCR) test specific for the 2009 H1N1 influenza A virus. Viruses isolated from nasopharyngeal swabs were genetically characterized using Sanger sequencing of uncloned “bulk” PCR products.

Main outcome measures  Virus sequencing to investigate nosocomial transmission.

Results  Two immunocompromised patients and four healthcare workers were found to be part of a nosocomial outbreak of the 2009 influenza A (H1N1) virus. One immunocompromised patient had a second episode of clinical influenza infection after isolation precautions had been discontinued, resulting in additional exposures. Strain‐specific PCR showed that all cases were caused by infection of the 2009 H1N1 virus. Sequencing of viral genes encoding hemagglutinin and polymerase basic subunit 2 (PB2) revealed that all viruses isolated were genetically identical at these loci, including the two episodes occurring in the same immunocompromised patient.

Conclusions  Prompt institution of isolation precautions is essential in preventing nosocomial outbreaks of the 2009 novel influenza A (H1N1) virus. Our data suggest that isolation precautions may need to be continued for a prolonged period of time in immunocompromised patients with influenza infection.

Pulmonary manifestation of novel swine-origin influenza A (H1N1) virus (S-OIV) infection in immunocompromised patients: initial findings with multidetector computed tomography

OBJECTIVE

To describe initial multidetector computed tomographic (MDCT) findings of novel swine-origin influenza A (H1N1) virus (S-OIV) infection in immunocompromised patients and to evaluate whether or not identification of certain abnormalities can help predict patients who are at risk for a severe clinical course.

SUBJECTS AND METHODS

This retrospective study included 13 patients with confirmed S-OIV infection suffering from an underlying immunodeficiency or who were receiving immunosuppressive therapy. All patients underwent MDCT of the thorax due to respiratory distress. All data were read by two independent radiologists who described the type and pattern of opacities, distribution and extent of the abnormalities observed. Adverse outcome measures were defined as acute respiratory distress syndrome with the need for mechanical ventilation, extracorporeal membrane oxygenation or death.

RESULTS

MDCT revealed pulmonary manifestations in 12 (92%) of 13 individuals. Six (50%) patients showed an adverse outcome with development of acute respiratory distress syndrome, 4 of these died. The most common findings were ground-glass opacities (10/12; 83%) and pulmonary consolidation (7/12; 58%) predominantly with a bilateral distribution. Reticular pattern and a tree-in-bud appearance were found in 3/12 (25%), respectively. Bilateral opacities with extensive involvement of the lung parenchyma were most predictive of a severe clinical course.

CONCLUSION

The MDCT scan in immunocompromised patients with confirmed S-OIV infection frequently revealed pulmonary abnormalities, which included ground-glass opacities and consolidations. Therefore, prediction of an adverse clinical outcome could be made in patients with MDCT findings demonstrating bilateral extensive consolidations, often combined with ground-glass opacities.

Predictors of symptoms of posttraumatic stress in Chinese university students during the 2009 H1N1 influenza pandemic

Background

The university environment poses a high risk of spreading infectious diseases, particularly the 2009 pandemic influenza H1N1, as it is a mass gathering place for youth. This study aimed to evaluate the predictors of stress symptoms among Chinese university students during the 2009 H1N1 influenza pandemic.

Material/Methods

We used a self-reported questionnaire, the PTSD (posttraumatic stress disorder) Checklist-Civilian Version (PCL-C) to evaluate the stress symptoms among Chinese university students from Heilongjiang (n=455), Beijing (n=106), Shanghai (n=419) and Sichuan (n=102). We then analyzed the predictors of stress symptoms.

Results

The proportion of university students enrolled in this study who met symptomatic criteria for PTSD was 2% (22 students). The mean PCL-C total score in the sample was 22.09±8.01. The correlational analyses revealed a significant positive relationship between the PCL-C total score and area, and university grade (P<0.01). Moreover, a negative relationship was found between the PCL-C total score and gender, having H1N1 influenza, having family members, friends or acquaintances having H1N1 influenza, and being afraid of H1N1 influenza (P<0.01). The regression analyses showed that in North China, female gender, having H1N1 influenza, having family members or acquaintances with H1N1 influenza, and being afraid of H1N1 influenza were significant predictors of the stress symptoms.

Conclusions

In North China, female gender, having H1N1 influenza, having family members, friends, or acquaintances with H1N1 influenza, and being afraid of H1N1 influenza were significant predictors of the stress symptoms.

Hospitalization of pregnant women with pandemic A(H1N1) 2009 influenza in Canada

This article describes the epidemiology of pandemic A(H1N1) 2009 influenza in all Canadian pregnant women admitted to hospital, and compares it with historical inter-pandemic influenza activity. We used weekly hospitalization and death counts of laboratory-confirmed pandemic A(H1N1) influenza cases reported to the Public Health Agency of Canada's (PHAC) 2009-2010 national pandemic influenza surveillance programme. Pregnant women infected and admitted with the pandemic strain were described and compared with: (1) confirmed admissions of all women of reproductive age; (2) all admitted cases reported to PHAC; and (3) to a historical average of inter-pandemic seasonal influenza admissions, and pneumonia and influenza (P&I) admissions for pregnant women. During the pandemic, 263 pregnant women with confirmed infections were admitted; four died in their third trimester. The median age for admitted pregnant cases was 27.5 years, which is consistent with the median age of the 3-year historical inter-pandemic pregnant comparison group. Aboriginal women appeared to be overrepresented but ethnicity was unavailable for 15.2% of all pregnant cases. Overall admission volumes were higher than those for seasonal influenza in the historical comparison group but were lower than those for P&I admissions. Despite increased admission volumes, severe outcomes in pregnant women were proportionally fewer than in all cases admitted for influenza A(H1N1) infection during the pandemic.

Immune response to pandemic H1N1 2009 influenza a vaccination in pediatric liver transplant recipients

After the announcement of a worldwide pandemic in June 2009, a single dose of a monovalent pandemic H1N1 2009 influenza A (pH1N1/09) vaccine was advocated for all Australians who were 10 years and older because of excellent immunogenicity trial results for healthy children and adults. Immunocompromised patients have previously been shown to have lower seroconversion rates after routine vaccinations. There is a lack of data concerning the immune response of this patient group after pH1N1/09 vaccination. The aim of this study was to assess the immunogenicity of a pH1N1/09 vaccine in pediatric liver transplant recipients 10 years of age or older. Liver transplant recipients ≥ 10 years were prospectively recruited. All participants were administered a single intramuscular injection of the pH1N1/09 vaccine (15 μg). Serum antibody levels were determined by hemagglutination immediately before and ≥ 6 weeks after vaccination. Clinical and laboratory data (age, time since transplantation, immunosuppression, and lymphocyte counts) were analyzed comparing seroconverters and nonconverters with the Student's t test. A second dose of the vaccine was offered to all those who displayed no seroprotective titers after the first vaccination. Antibody levels were again determined 6 weeks later. Twenty-one of 28 liver transplant patients completed the study. The seroconversion rate was 62% after the first dose and 89.5% after the second dose. At baseline, 7 of 21 patients (33.4%) were already seropositive. Increasing time since transplantation positively correlated with successful seroconversion. In conclusion, a single dose of a pandemic influenza A vaccine does not elicit a reliable immune response in adolescent pediatric liver transplant patients. A second dose of the vaccine is warranted in this group of patients, at least in a pandemic scenario. There is an urgent need to further assess vaccine strategies in this high-risk group.

The effect of influenza virus A on th1/th2 balance and alveolar fluid clearance in pregnant rats

ABSTRACT Pregnant women are more prone to H1N1 infection and often with severe complications. The authors studied the influence of H1N1 infection on T-helper cell type 1/type 2 (Th1/Th2) balance and alveolar fluid clearance (AFC) in pregnant rats. The pregnant rats were infected intranasally with influenza virus. Peripheral blood interferon-γ (IFN-γ) and interleukin-4 (IL-4) were measured by enzyme-linked immunosorbent assay (ELISA) and AFC was estimated by albumin concentration in alveolar lavage. The ratio of IFN-γ/IL-4 in nonpregnant rats was 21 ± 7. There was significant increase in both cytokines in infected pregnant rats compared with noninfected counterparts, with dramatic reduction in IFN-γ/IL-4 ratio (8 ± 3) compared to that (15 ± 8) in normal pregnant group. AFC of normal nonpregnant rats was 17% ± 3% and H1N1 infection reduced it to 11% ± 2%. AFC of normal pregnant rats was 22% ± 2% and H1N1 infection reduced it to 10% ± 2%. Dexamethasone reversed AFC in both nonpregnant and pregnant groups (14% ± 4% and 13% ± 2%, respectively). These results show that influenza virus A infection leads to Th2-biased immunity and reduces AFC in normal rats, and further worsens these in pregnant rats. Dexamethasone reverses these effects in both pregnant and nonpregnant rats.

Pandemic (H1N1) 2009 virus infection during pregnancy in South India

OBJECTIVE

To assess the clinical profile of pregnant/puerperal women from a semi-urban Indian population who were infected with pandemic (H1N1) 2009 virus (P[H1N1]2009v) and to evaluate their outcome.

METHODS

In a cross-sectional study, 566 women (79 pregnant/puerperal, 487 nonpregnant) who presented to a tertiary care hospital with influenza-like illness were tested for P(H1N1)2009v by real-time reverse transcriptase polymerase chain reaction. Outcomes measures were the maternal mortality and the perinatal mortality rate (PMR).

RESULTS

Twenty (25%) pregnant/puerperal and 144 (30%) nonpregnant women tested positive for P(H1N1)2009v, with 5 pregnant and 3 postpartum women requiring admission to the intensive care unit (ICU). P(H1N1)2009v-related mortality was higher in pregnant than nonpregnant women (25% versus 8%; P=0.04). In the pregnant/puerperal cohort, factors associated with death included delayed presentation (median 6days versus 1.5days in survivors; P=0.007), need for ICU admission (P=0.004), need for ventilation (P=0.001), and renal failure (P=0.001). The PMR was 55.5/1000 births compared with 33.5/1000 births in the hospital overall during the study period.

CONCLUSION

In a low-income country, P(H1N1)2009v infection in pregnancy is associated with considerable mortality. Delayed presentation to a tertiary care center, lack of awareness, and restricted access to treatment might have contributed to the high mortality.

2009 pandemic influenza A (H1N1) in pregnancy: a systematic review of the literature

To summarize the literature regarding 2009 H1N1 influenza A during pregnancy, we conducted a systematic literature review using a PubMed search and other strategies. Studies were included if they reported 2009 H1N1 influenza in pregnant women as original data. In all, 2153 abstracts were reviewed, and a total of 120 studies were included. Data were extracted regarding number of cases, additional risk factors for influenza-associated complications, treatment, and maternal and pregnancy outcomes. Authors were contacted to determine the extent of overlap when it was suspected. Pregnancy was associated with increased risk of hospital and intensive care unit admission and of death. Pregnant women who received delayed treatment with neuraminidase inhibitors or who had additional risk factors were more likely to develop severe disease. Preterm and emergency cesarean deliveries were frequently reported. These results reinforce the importance of early identification and treatment of suspected influenza in this high-risk population.

Influenza in immunocompromised patients: considerations for therapy

Influenza infection results in substantial morbidity and mortality in immunocompromised patients, and the risks for influenza and its related complications depend on the degree of immunosuppression. In addition to influenza vaccination and infection control precautions, two classes of antiviral drugs are currently approved for treatment and prophylaxis in uncomplicated infected patients. However, there are no randomized controlled trials assessing the efficacy and safety of licensed antivirals for influenza management in immunocompromised patients. The purpose of this article is to highlight some considerations for therapy in immunocompromised patients, the usefulness of vaccination for the prevention of influenza and the clinical interest in surveillance of antiviral resistance.

Novel influenza a (H1N1) infection in a Pediatric Hematology Oncology Clinic during the 2009-2010 pandemia

Pandemic influenza A infection (2009 H1N1) was associated with a worldwide outbreak of febrile respiratory infection. Although usually it results in a mild illness, certain patient groups are at increased risk for complications. The authors reviewed their experience in a pediatric hematology-oncology unit to determine the outcome of this disease in children with hematological conditions and solid tumors. During the second outbreak (1 November 2009 to 14 January 2010), a total of 187 children from pediatric clinic were tested for H1N1 influenza A by multiplex polymerase chain reaction (PCR), 63 of them were positive. Patients' signs and symptoms were recorded prospectively. Ten (35.7%) (5 children with solid tumors, 4 with leukemia, 1 with hereditary spherocytosis) of 28 tested children with hematological conditions were diagnosed with 2009 H1N1 influenza infection. Fever (100%) and cough (90%) were the most common symptoms. Five were neutropenic (neutrophil count <1000/mm(3)), 4 had severe neutropenia (neutrophil count <500/mm(3)). Systemic antibiotics were given in 5 patients with the diagnosis of febrile neutropenia. Four were inpatients, others were hospitalized after the diagnosis. One patient required mechanical ventilation; however, he had concomitant invasive fungal infection. Eight patients were treated by oseltamivir, all tolerated the drug well. A total of 4 cases from 9 cancer patients had a delay in their planned chemotherapy for 7 to 15 days. Pandemic H1N1 influenza caused mild symptoms in children with cancer and/or hematological conditions but resulted in delay in anticancer therapy and increase in hospitalization and antibiotic usage.

Vaccination of health-care workers against influenza: our obligation to protect patients

Please cite this paper as: Maltezou and Tsakris. (2011) Vaccination of health‐care workers against influenza: our obligation to protect patients. Influenza and Other Respiratory Viruses 5(6), 382–388.

Nosocomial influenza poses a threat for specific groups of patients and is associated not only with the disruption of health‐care services but also excess costs. Although vaccination of health‐care workers (HCWs) has been recommended for almost three decades and constitutes the most convenient and effective means to prevent nosocomial transmission, vaccine uptake within this group remains unacceptably low worldwide. In regard to the pandemic influenza A H1N1, HCWs constitute a priority group for immunization. Nevertheless, low vaccination rates have been documented regarding the influenza pandemic and associated with the onset of nosocomial cases and outbreaks. HCWs, health‐care institutions, and public health bodies have the moral obligation to protect vulnerable patients and therefore weigh the benefits of mandatory vaccination. Key effective interventions, such as the education of HCWs concerning the benefits and safety of influenza vaccination, the reinforcement of on‐site, free of charge vaccinations, and the use of mobile vaccination teams in conjunction with incentives, should be widely implemented.

[Clinical features of influenza A H1N1 2009: a multicentre study]

OBJECTIVE

To describe clinical and epidemiological features of influenza A H1N1 2009 diagnosed patients in the Emergency Department of 4 hospitals.

MATERIAL AND METHODS

Prospective multicentre study conducted from july to december 2009. The patients diagnosed by Real-Time PCR of influenza A H1N1 2009 in the emergency department were included. The test was requested according to the protocols established throughout the epidemic. Epidemiological, clinical, laboratory variables and outcomes were evaluated.

RESULTS

A total of 456 cases were included, with a median age of 6.5years (PC(25-75) 3-10.6). There were risk factors of complications In 266 patients (59.4%) due to the influenza, mainly: respiratory (47%), cardiovascular (17%), neurological (14%) and immunosuppression (11%). The most frequent symptoms were fever (96%), (88%) cough, (72%) rhinorrhoea, muscle aches or asthenia and breathing difficulties and, less common, gastrointestinal and neurological symptoms. Chest X-ray was performed on 224 cases (49%), with lobar (31%) and interstitial (15%) infiltrates. One hundred and forty patients (31%) were hospitalised and 3.2% required Intensive Care Unit (median stay 4 and 3.5days, respectively). The most frequent complications were pneumonias and bronchospasms. Three patients died (a previously healthy patient with myocarditis and 2 patients with encephalopathy due to respiratory failure). Another case of myocarditis recovered with sequelae.

CONCLUSIONS

The profile of patient with influenza A 2009 diagnosed in the emergency department was a school child, with risk factors of complications, presenting with respiratory symptoms and fever over a short time, and who can be discharged. It is important to emphasise myocarditis, as well as the usual respiratory complications of influenza virus.

Management of the 2009 A/H1N1 influenza pandemic in patients with hematologic diseases: a prospective experience at an Italian center

Data derived from epidemiologic surveillance adopted at our center in hematologic and stem cell transplant patients during the 2009 influenza A (H1N1)v pandemic are reported. Of the 52 patients with influenza-like disease we observed, 37 underwent a real-time PCR evaluation and 21 had a confirmed diagnosis. Of the RT-PCR-confirmed cases, 23.8% were children (age <18 years) and 9.5% were >65 years; 47.6% presented with a pulmonary infiltrate and 33.3% with respiratory failure. Pulmonary involvement was observed more frequently in patients with comorbidities. All patients received a course of oseltamivir therapy starting an average of 1 day (range <1-2) after the onset of symptoms. No patient was transferred to the intensive care unit. The viral disease had a generally favorable outcome despite the high frequency of pulmonary involvement. A prompt clinical evaluation with an early antiviral and supportive therapy may have played a beneficial role in the outcome.

Pandemic influenza A (H1N1) in pregnant women: impact of early diagnosis and antiviral treatment

Pregnant women are at increased risk for severe illness from influenza infection, particularly pandemics, including the current flu pandemic. Early antiviral therapy using oseltamivir or zanamivir may be beneficial, but limited information is available regarding their safety and effectiveness during pregnancy. The article by Siston et al. assessed the findings of a recently published paper describing the severity of illness due to 2009 influenza A (H1N1) infection among 788 pregnant women reported to the CDC, stratified by timing of antiviral therapy and pregnancy trimester at symptom onset. The authors' findings highlight the potential for severe illness and high risk of mortality due to influenza A (H1N1) infection among pregnant women and suggest the benefit of early antiviral treatment in reducing intensive care unit admissions and mortality rate. The WHO and CDC recommendations including 2009 influenza A (H1N1) vaccination and early antiviral therapy in case of influenza-like illness for all pregnant women are discussed regarding the key findings of this paper and other published data on influenza A (H1N1) infection in pregnant women.

The clinical features and outcome of 2009 H1N1 influenza infection in allo-SCT patients: a British Society of Blood and Marrow Transplantation study

The clinical course of 2009 H1N1 influenza in Allo-SCT patients is unknown. Data were collected in the UK from October 2009 to April 2010 on laboratory-confirmed cases of H1N1 influenza in Allo-SCT recipients. H1N1 infection was diagnosed in 60 patients, median age 42 years, at a median of 10 months post-SCT. Twenty-one patients (35%) developed pneumonia and nine (15%) required admission to intensive care units. Actuarial mortality was 7% at 28 days and 19% 4 months post-diagnosis of 2009 H1N1 influenza. Increasing age and pre-existing lung disease were risk factors for pneumonia (P=0.006 and 0.037, respectively); older age was a risk factor for death (P=0.012). Morbidity and mortality from 2009 H1N1 influenza in SCT patients exceeds that of immunocompetent patients, but parallels that in other critically ill hospitalised cohorts; the elderly and those with chronic pulmonary disease are at greatest risk.

H1N1pdm influenza infection in hospitalized cancer patients: clinical evolution and viral analysis

Background

The novel influenza A pandemic virus (H1N1pdm) caused considerable morbidity and mortality worldwide in 2009. The aim of the present study was to evaluate the clinical course, duration of viral shedding, H1N1pdm evolution and emergence of antiviral resistance in hospitalized cancer patients with severe H1N1pdm infections during the winter of 2009 in Brazil.

Methods

We performed a prospective single-center cohort study in a cancer center in Rio de Janeiro, Brazil. Hospitalized patients with cancer and a confirmed diagnosis of influenza A H1N1pdm were evaluated. The main outcome measures in this study were in-hospital mortality, duration of viral shedding, viral persistence and both functional and molecular analyses of H1N1pdm susceptibility to oseltamivir.

Results

A total of 44 hospitalized patients with suspected influenza-like illness were screened. A total of 24 had diagnosed H1N1pdm infections. The overall hospital mortality in our cohort was 21%. Thirteen (54%) patients required intensive care. The median age of the studied cohort was 14.5 years (3–69 years). Eighteen (75%) patients had received chemotherapy in the previous month, and 14 were neutropenic at the onset of influenza. A total of 10 patients were evaluated for their duration of viral shedding, and 5 (50%) displayed prolonged viral shedding (median 23, range = 11–63 days); however, this was not associated with the emergence of a resistant H1N1pdm virus. Viral evolution was observed in sequentially collected samples.

Conclusions

Prolonged influenza A H1N1pdm shedding was observed in cancer patients. However, oseltamivir resistance was not detected. Taken together, our data suggest that severely ill cancer patients may constitute a pandemic virus reservoir with major implications for viral propagation.

[Novel influenza A (H1N1) infection in immunocompromised patients]

BACKGROUND

Since April 2009, novel influenza A (H1N1) infection is spreading throughout the world. This infection might be fatal for immunocompromised patients who are at a potentially high risk of developing infectious complications. We investigated the detection rate and features of H1N1 infection in immunocompromised patients.

METHODS

Between August 2009 and February 2010, we examined 8,112 subjects, including 390 immunocompromised patients, for H1N1. Swab samples were taken from the nose and throat of the participants. Real-time PCR was performed to identify H1N1 viral genes.

RESULTS

Positive results were obtained in 2,953/8,112 (36.4%) subjects and 46/390 (11.8%) immunocompromised patients. H1N1 was identified in 8.7% patients with solid cancer, 12.9% patients with hematologic malignancy, 16.7% patients with chronic renal disease, and 14.5% patients with kidney transplantation. The mean cycle threshold (Ct) value of PCR was significantly lower (P<0.05) in patients with hematologic malignancy as compared to that in patients with chronic renal disease and control subjects. Four patients died due to respiratory complications.

CONCLUSIONS

The detection rate of H1N1 was significantly lower in immunocompromised patients than in other patients. The Ct value of patients with hematologic malignancy was significantly lower than that of other immunocompromised patients and control subjects.

The impact of sex, gender and pregnancy on 2009 H1N1 disease

Children and young adults of reproductive age have emerged as groups that are highly vulnerable to the current 2009 H1N1 pandemic. The sex of an individual is a fundamental factor that can influence exposure, susceptibility and immune responses to influenza. Worldwide, the incidence, disease burden, morbidity and mortality rates following exposure to the 2009 H1N1 influenza virus differ between males and females and are often age-dependent. Pregnancy and differences in the presentation of various risk factors contribute to the worse outcome of infection in women. Vaccination and antiviral treatment efficacy also vary in a sex-dependent manner. Finally, sex-specific genetic and hormonal differences may contribute to the severity of influenza and the clearance of viral infection. The contribution of sex and gender to influenza can only be determined by a greater consideration of these factors in clinical and epidemiological studies and increased research into the biological basis underlying these differences.