Influenza epidemiology--past, present, and future

Novel Core Gene Signature Associated with Inflammation-to-Metaplasia Transition in Influenza A Virus-Infected Lungs

Respiratory infections caused by RNA viruses are a major contributor to respiratory disease due to their ability to cause annual epidemics with profound public health implications. Influenza A virus (IAV) infection can affect a variety of host signaling pathways that initiate tissue regeneration with hyperplastic and/or dysplastic changes in the lungs. Although these changes are involved in lung recovery after IAV infection, in some cases, they can lead to serious respiratory failure. Despite being ubiquitously observed, there are limited data on the regulation of long-term recovery from IAV infection leading to normal or dysplastic repair represented by inflammation-to-metaplasia transition in mice or humans. To address this knowledge gap, we used integrative bioinformatics analysis with further verification in vivo to elucidate the dynamic molecular changes in IAV-infected murine lung tissue and identified the core genes (Birc5, Cdca3, Plk1, Tpx2, Prc1. Rrm2, Nusap1, Spag5, Top2a, Mcm5) and transcription factors (E2F1, E2F4, NF-YA, NF-YB, NF-YC) involved in persistent lung injury and regeneration processes, which may serve as gene signatures reflecting the long-term effects of IAV proliferation on the lung. Further analysis of the identified core genes revealed their involvement not only in IAV infection but also in COVID-19 and lung neoplasm development, suggesting their potential role as biomarkers of severe lung disease and its complications represented by abnormal epithelial proliferation and oncotransformation.

Forecasting seasonal influenza activity in Canada-Comparing seasonal Auto-Regressive integrated moving average and artificial neural network approaches for public health preparedness

INTRODUCTION

Public health preparedness is based on timely and accurate information. Time series forecasting using disease surveillance data is an important aspect of preparedness. This study compared two approaches of time series forecasting: seasonal auto-regressive integrated moving average (SARIMA) modelling and the artificial neural network (ANN) algorithm. The goal was to model weekly seasonal influenza activity in Canada using SARIMA and compares its predictive accuracy, based on root mean square prediction error (RMSE) and mean absolute prediction error (MAE), to that of an ANN.

METHODS

An initial SARIMA model was fit using automated model selection by minimizing the Akaike information criterion (AIC). Further inspection of the autocorrelation function and partial autocorrelation function led to 'manual' model improvements. ANNs were trained iteratively, using an automated process to minimize the RMSE and MAE.

RESULTS

A total of 378, 462 cases of influenza was reported in Canada from the 2010-2011 influenza season to the end of the 2019-2020 influenza season, with an average yearly incidence risk of 20.02 per 100,000 population. Automated SARIMA modelling was the better method in terms of forecasting accuracy (per RMSE and MAE). However, the ANN correctly predicted the peak week of disease incidence while the other models did not.

CONCLUSION

Both the ANN and SARIMA models have shown to be capable tools in forecasting seasonal influenza activity in Canada. It was shown that applying both in tandem is beneficial, SARIMA better forecasted overall incidence while ANN correctly predicted the peak week.

High-throughput sequencing approaches applied to SARS-CoV-2

High-throughput sequencing is crucial for surveillance and control of viral outbreaks. During the ongoing coronavirus disease 2019 (COVID-19) pandemic, advances in the high-throughput sequencing technology resources have enhanced diagnosis, surveillance, and vaccine discovery. From the onset of the pandemic in December 2019, several genome-sequencing approaches have been developed and supported across the major sequencing platforms such as Illumina, Oxford Nanopore, PacBio, MGI DNBSEQTM and Ion Torrent. Here, we share insights from the sequencing approaches developed for sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between December 2019 and October 2022.

Influenza Virus Infection during Pregnancy as a Trigger of Acute and Chronic Complications

Influenza A virus (IAV) infection during pregnancy disrupts maternal and fetal health through biological mechanisms, which are to date poorly characterised. During pregnancy, the viral clearance mechanisms from the lung are sub-optimal and involve hyperactive innate and adaptive immune responses that generate wide-spread inflammation. Pregnancy-related adaptations of the immune and the cardiovascular systems appear to result in delayed recovery post-viral infection, which in turn promotes a prolonged inflammatory phenotype, increasing disease severity, and causing maternal and fetal health problems. This has immediate and long-term consequences for the mother and fetus, with complications including acute cardiopulmonary distress syndrome in the mother that lead to perinatal complications such as intrauterine growth restriction (IUGR), and birth defects; cleft lip, cleft palate, neural tube defects and congenital heart defects. In addition, an increased risk of long-term neurological disorders including schizophrenia in the offspring is reported. In this review we discuss the pathophysiology of IAV infection during pregnancy and its striking similarity to other well-established complications of pregnancy such as preeclampsia. We discuss general features of vascular disease with a focus on vascular inflammation and define the "Vascular Storm" that is triggered by influenza infection during pregnancy, as a pivotal disease mechanism for short and long term cardiovascular complications.

Novel β-Cyclodextrin-Based Heptavalent Glycyrrhetinic Acid Conjugates: Synthesis, Characterization, and Anti-Influenza Activity

In our continuing efforts toward the design of novel pentacyclic triterpene derivatives as potential anti-influenza virus entry inhibitors, a series of homogeneous heptavalent glycyrrhetinic acid derivatives based on β-cyclodextrin scaffold were designed and synthesized by click chemistry. The structure was unambiguously characterized by NMR, IR, and MALDI-TOF-MS measurements. Seven conjugates showed sufficient inhibitory activity against influenza virus infection based on the cytopathic effect reduction assay with IC50 values in the micromolar range. The interactions of conjugate 37, the most potent compound (IC50 = 2.86 μM, CC50 > 100 μM), with the influenza virus were investigated using the hemagglutination inhibition assay. Moreover, the surface plasmon resonance assay further confirmed that compound 37 bound to the influenza HA protein specifically with a dissociation constant of 5.15 × 10−7 M. Our results suggest the promising role of β-cyclodextrin as a scaffold for preparing a variety of multivalent compounds as influenza entry inhibitors.

A Single Vaccine Protects against SARS-CoV-2 and Influenza Virus in Mice

The ongoing SARS-CoV-2 pandemic poses a severe global threat to public health, as do influenza viruses and other coronaviruses. Here, we present chimpanzee adenovirus 68 (AdC68)-based vaccines designed to universally target coronaviruses and influenza. Our design is centered on an immunogen generated by fusing the SARS-CoV-2 receptor-binding domain (RBD) to the conserved stalk of H7N9 hemagglutinin (HA). Remarkably, the constructed vaccine effectively induced both SARS-CoV-2-targeting antibodies and anti-influenza antibodies in mice, consequently affording protection from lethal SARS-CoV-2 and H7N9 challenges as well as effective H3N2 control. We propose our AdC68-vectored coronavirus-influenza vaccine as a universal approach toward curbing respiratory virus-causing pandemics. IMPORTANCE The COVID-19 pandemic exemplifies the severe public health threats of respiratory virus infection and influenza A viruses. The currently envisioned strategy for the prevention of respiratory virus-causing diseases requires the comprehensive administration of vaccines tailored for individual viruses. Here, we present an alternative strategy by designing chimpanzee adenovirus 68-based vaccines which target both the SARS-CoV-2 receptor-binding-domain and the conserved stalk of influenza hemagglutinin. When tested in mice, this strategy attained potent neutralizing antibodies against wild-type SARS-CoV-2 and its emerging variants, enabling an effective protection against lethal SARS-CoV-2 challenge. Notably, it also provided complete protection from lethal H7N9 challenge and efficient control of H3N2-induced morbidity. Our study opens a new avenue to universally curb respiratory virus infection by vaccination.

Facial Synthesis and Bioevaluation of Well-Defined OEGylated Betulinic Acid-Cyclodextrin Conjugates for Inhibition of Influenza Infection

Betulinic acid (BA) and its derivatives exhibit a variety of biological activities, especially their anti-HIV-1 activity, but generally have only modest inhibitory potency against influenza virus. The entry of influenza virus into host cells can be competitively inhibited by multivalent derivatives targeting hemagglutinin. In this study, a series of hexa-, hepta- and octavalent BA derivatives based on α-, β- and γ-cyclodextrin scaffolds, respectively, with varying lengths of flexible oligo(ethylene glycol) linkers was designed and synthesized using a microwave-assisted copper-catalyzed 1,3-dipolar cycloaddition reaction. The generated BA-cyclodextrin conjugates were tested for their in vitro activity against influenza A/WSN/33 (H1N1) virus and cytotoxicity. Among the tested compounds, 58, 80 and 82 showed slight cytotoxicity to Madin-Darby canine kidney cells with viabilities ranging from 64 to 68% at a high concentration of 100 μM. Four conjugates 51 and 69–71 showed significant inhibitory effects on influenza infection with half maximal inhibitory concentration values of 5.20, 9.82, 7.48 and 7.59 μM, respectively. The structure-activity relationships of multivalent BA-cyclodextrin conjugates were discussed, highlighting that multivalent BA derivatives may be potential antiviral agents against influenza infection.

A critical care pandemic staffing framework in Australia

Background

Pandemics and the large-scale outbreak of infectious disease can significantly impact morbidity and mortality worldwide. The impact on intensive care resources can be significant and often require modification of service delivery, a key element which includes rapid expansion of the critical care workforce. Pandemics are also unpredictable, which necessitates rapid decision-making and action which, in the lack of experience and guidance, may be extremely challenging. Recognising the potential strain on intensive care units (ICUs), particularly on staffing, a working group was formed for the purpose of developing recommendations to support decision-making during rapid service expansion.

Methods

The Critical Care Pandemic Staffing Working Party (n = 21), representing nursing, allied health, and medical disciplines, has used a modified consensus approach to provide recommendations to inform multidisciplinary workforce capacity expansion planning in critical care.

Results

A total of 60 recommendations have been proposed which reflect general recommendations as well as those specific to maintaining the critical care workforce, expanding the critical care workforce, rostering and allocation of the critical care workforce, nurse-specific recommendations for staffing the ICU, education support and training during ICU surge situations, workforce support, models of care, and de-escalation.

Conclusion

These recommendations are provided with the intent that they be used to guide interdisciplinary decision-making, and we suggest that careful consideration is given to the local context to determine which recommendations are most appropriate to implement and how they are prioritised. Ongoing evaluation of recommendation implementation and impact will be necessary, particularly in rapidly changing clinical contexts.

Public health nurses' experiences during the H1N1/09 response

OBJECTIVE

H1N1/09 was the first pandemic flu ever responded to with mass vaccinations. Public health nurses (PHNs) were pivotal in implementing the H1N1/09 vaccination clinics. With the ongoing threat of pandemic influenza and other viral outbreaks, much can be learned from these PHNs' H1N1/09 experiences. This study's purpose was to explore PHNs' experiences in the H1N1/09 mass vaccination clinics.

DESIGN AND SAMPLE

In a qualitative interpretive description, 23 PHNs (16 immunizers, seven supervisors) who worked in a large Canadian municipal public health agency, participated in semistructured interviews.

RESULTS

Three overarching themes were identified. 'Anticipating an Emergency' discusses participants' experiences learning about the pandemic response and their role preparation. 'Surviving the Chaos' reflects the challenges of the clinics, particularly during the first few hectic weeks of the response. 'Persevering Over Time' encompasses participants' experiences as they became familiar with clinics' operations and their own responsibilities.

CONCLUSIONS

Participants' experiences have implications for future public health pandemic planning and research. Key recommendations include to communicate with PHNs in a timely manner about their clinic roles, and to provide PHNs with appropriate training to optimize clinics' operations. This will help support PHNs in their roles to protect the public and provide quality population care.

Epidemiology of influenza in Ethiopia: findings from influenza sentinel surveillance and respiratory infection outbreak investigations, 2009-2015

BACKGROUND

Influenza is an acute viral disease of the respiratory tract which is characterized by fever, headache, myalgia, prostration, coryza, sore throat and cough. Globally, an estimated 3 to 5 million cases of severe influenza illness and 291 243-645 832 seasonal influenza-associated respiratory deaths occur annually. Although recent efforts from some African countries to describe burden of influenza disease and seasonality, these data are missing for the vast majority, including Ethiopia. Ethiopia established influenza sentinel surveillance in 2008 aiming to determine influenza strains circulating in the country and know characteristics, trend and burden of influenza viruses.

METHODS

We used influenza data from sentinel surveillance sites and respiratory disease outbreak investigations from 2009 to 2015 for this analysis. We obtained the data by monitoring patients with influenza-like illness (ILI) at three health-centers, severe acute respiratory infection (SARI) at five hospitals and investigating patients during different respiratory infection outbreaks. Throat-swab specimens in viral transport media were transported to the national reference laboratory within 72 h of collection using a cold-chain system. We extracted viral RNA from throat-swabs and subjected to real-time PCR amplification. We further subtyped and characterized Influenza A-positive specimens using CDC real-time reverse transcription PCR protocol.

RESULTS

A total of 4962 throat-swab samples were collected and 4799 (96.7%) of them were tested. Among them 988 (20.6%) were influenza-positive and of which 349 (35.3%) were seasonal influenza A(H3N2), 321 (32.5%) influenza A(H1N1)pdm2009 and 318 (32.0%) influenza B. Positivity rate was 29.5% in persons 5-14 years followed by 26.4% in 15-44 years, 21.2% in > 44 years and 6.4% in under five children. The highest positivity rate observed in November (37.5%) followed by March (27.6%), December (26.4%), October (24.4%) and January (24.3%) while the lowest positivity rate was in August (7.7%).

CONCLUSION

In Ethiopia, seasonal Influenza A(H3N2), Influenza A(H1N1)pdm2009 and Influenza B viruses were circulating during 2009-2015. Positivity rate and number of cases peaked in November and December. Influenza is one of public health problems in Ethiopia and the need to introduce influenza vaccine and antivirus is important to prevent and treat the disease in future.

The burden of influenza A and B in Mexico from the year 2010 to 2013: An observational, retrospective, database study, on records from the Directorate General of Epidemiology database

Despite vaccination programs, influenza still represents a significant disease burden in Mexico. We conducted an observational, retrospective analysis to better understand the epidemiological situation of the influenza virus in Mexico. Analysis of the seasonal patterns of influenza A and B were based on the Directorate General of Epidemiology dataset of influenza-like illness(ILI), and severe acute respiratory infection(SARI) that were recorded between January 2010 and December 2013. Our objectives were 1) to describe influenza A and B activity, by age group, and subtype and, 2) to analyze the number of laboratory-confirmed cases presenting with ILI by influenza type, the regional distribution of influenza, and its clinical features. Three periods of influenza activity were captured: August 2010-January 2011, December 2011-March 2012, and October 2012-March 2013. Cases were reported throughout Mexico, with 50.3% (n = 10,320) of cases found in 18-49 year olds. Over the entire capture period, a total of 76,085 ILI/SARI episodes had swab samples analyzed for influenza, 27% were positive. During the same period, influenza A cases were higher in the 18-49 years old, and influenza B cases in both 5-17 and 18-49 age groups. Peak activity occurred in January 2012 (n = 4,159) and December 2012 (n = 348) for influenza A and B respectively. This analysis confirms that influenza is an important respiratory pathogen for children and adults in Mexico despite vaccination recommendations. School-age children and adolescents were more prone to influenza B infection; while younger adults were susceptible to both influenza A and B viruses. Over the seasons, influenza A and B co-circulated.

Inhibition of influenza virus infection by multivalent pentacyclic triterpene-functionalized per-O-methylated cyclodextrin conjugates

Multivalent ligands that exhibit high binding affinity to influenza hemagglutinin (HA) trimer can block the interaction of HA with its sialic acid receptor. In this study, a series of multivalent pentacyclic triterpene-functionalized per-O-methylated cyclodextrin (CD) derivatives were designed and synthesized using 1, 3-dipolar cycloaddition click reaction. A cell-based assay showed that three compounds (25, 28 and 31) exhibited strong inhibitory activity against influenza A/WSN/33 (H1N1) virus. Compound 28 showed the most potent anti-influenza activity with IC₅₀ of 4.7 μM. The time-of-addition assay indicated that compound 28 inhibited the entry of influenza virus into host cell. Further hemagglutination inhibition (HI) and surface plasmon resonance (SPR) assays indicated that compound 28 tightly bound to influenza HA protein with a dissociation constant (K_D) of 4.0 μM. Our results demonstrated a strategy of using per-O-methylated β-CD as a scaffold for designing multivalent compounds to disrupt influenza HA protein-host receptor protein interaction and thus block influenza virus entry into host cells.

Pulmonary changes in Norwegian fatal cases of pandemic influenza H1N1 (2009) infection: a morphologic and molecular genetic study

Background

During the pandemic outbreak of the 2009 swine influenza (A(H1N1)pdm09), 32 fatal cases occurred in Norway and 19 of these were included in this study.

Objectives

We characterised pulmonary changes in these fatal Norwegian cases.

Patients and Methods

Upon hospitalisation, detailed clinical information and specimens from the upper and lower respiratory pathways were collected. At post‐mortem, lung tissue was collected, formalin‐fixed and paraffin‐embedded. Immunohistochemical and light microscopic examination was performed to visualise the local expression of the A(H1N1)pdm09 virus. Reverse transcription‐polymerase chain reaction (RT‐PCR) and pyrosequencing of the non‐fixed specimens allowed the identification of mutations in the influenza virus surface glycoprotein (haemagglutinin gene) particularly at position 222.

Results and Conclusions

The overall course of illness lasted from 2 to 40 days (median 9 days). Diffused alveolar damage (DAD) was evident in 11 cases, 4 of which had no apparent underlying illness. Obesity was prominent in 12 cases, where three individuals were classified as otherwise healthy. The HA D222G mutation was detected in six cases, 3 of which had no underlying illness. Immunohistochemistry showed the A(H1N1)pdm09 virus to be prominent at the site of inflammation both in close proximity to and inside alveolar structures in the lung tissue. In addition to a possible role for the HA D222G mutation, our findings indicate that host factors and underlying conditions in the infected individuals are fundamental for disease outcome in many cases. This study increases our understanding of determinants for the clinical outcome of pandemic influenza, which could guide future treatment.

Fluzone® Intradermal Quadrivalent Influenza Vaccine

INTRODUCTION

An intradermal version of Fluzone® split-virion inactivated trivalent influenza vaccine, containing 9 µg hemagglutinin per strain of A/H1N1, A/H3N2, and one B lineage virus (Fluzone Intradermal, Sanofi Pasteur), became available in the US during the 2011-2012 influenza season for adults 18-64 years of age. In advance of the 2015-2016 season, Fluzone Intradermal was replaced with Fluzone Intradermal Quadrivalent vaccine, which contains 9 µg hemagglutinin per strain of the two A-strain viruses and both B-strain lineage viruses (Victoria and Yamagata).

AREAS COVERED

This literature review summarizes the history and mechanism of intradermal vaccination, discusses the clinical trial results supporting the immunogenicity and safety of Fluzone Intradermal Quadrivalent vaccine, and describes the unique microinjection system used to deliver Fluzone Intradermal Quadrivalent. Expert commentary: Fluzone Intradermal Quadrivalent may boost confidence in influenza vaccination with the addition of a second B-lineage strain. By using an innovative microinjection system, the vaccine is also designed to address some of the logistic challenges faced by healthcare providers administering immunizations.

Progress on adenovirus-vectored universal influenza vaccines

Influenza virus (IFV) infection causes serious health problems and heavy financial burdens each year worldwide. The classical inactivated influenza virus vaccine (IIVV) and live attenuated influenza vaccine (LAIV) must be updated regularly to match the new strains that evolve due to antigenic drift and antigenic shift. However, with the discovery of broadly neutralizing antibodies that recognize conserved antigens, and the CD8(+) T cell responses targeting viral internal proteins nucleoprotein (NP), matrix protein 1 (M1) and polymerase basic 1 (PB1), it is possible to develop a universal influenza vaccine based on the conserved hemagglutinin (HA) stem, NP, and matrix proteins. Recombinant adenovirus (rAd) is an ideal influenza vaccine vector because it has an ideal stability and safety profile, induces balanced humoral and cell-mediated immune responses due to activation of innate immunity, provides 'self-adjuvanting' activity, can mimic natural IFV infection, and confers seamless protection against mucosal pathogens. Moreover, this vector can be developed as a low-cost, rapid-response vaccine that can be quickly manufactured. Therefore, an adenovirus vector encoding conserved influenza antigens holds promise in the development of a universal influenza vaccine. This review will summarize the progress in adenovirus-vectored universal flu vaccines and discuss future novel approaches.

Differential Immune Profiles in Two Pandemic Influenza A(H1N1)pdm09 Virus Waves at Pandemic Epicenter

Background and Aims

Severe influenza A(H1N1)pdm2009 virus infection cases are characterized by sustained immune activation during influenza pandemics. Seasonal flu data suggest that immune mediators could be modified by wave-related changes. Our aim was to determine the behavior of soluble and cell-related mediators in two waves at the epicenter of the 2009 influenza pandemic.

Methods

Leukocyte surface activation markers were studied in serum from peripheral blood samples, collected from the 1^st (April–May, 2009) and 2^nd (October 2009–February 2010) pandemic waves. Patients with confirmed influenza A(H1N1)pdm2009 virus infection (H1N1), influenza-like illness (ILI) or healthy donors (H) were analyzed.

Results

Serum IL-6, IL-4 and IL-10 levels were elevated in H1N1 patients from the 2^nd pandemic wave. Additionally, the frequency of helper and cytotoxic T cells was reduced during the 1^st wave, whereas CD69 expression in helper T cells was increased in the 2^nd wave for both H1N1 and ILI patients. In contrast, CD62L expression in granulocytes from the ILI group was increased in both waves but in monocytes only in the 2^nd wave. Triggering Receptor Expressed on Myeloid cells (TREM)-1 expression was elevated only in H1N1 patients at the 1^st wave.

Conclusions

Our results show that during the 2009 influenza pandemic a T cell activation phenotype is observed in a wave-dependent fashion, with an expanded activation in the 2^nd wave, compared to the 1^st wave. Conversely, granulocyte and monocyte activation is infection-dependent. This evidence collected at the pandemic epicenter in 2009 could help us understand the differences in the underlying cellular mechanisms that drive the wave-related immune profile behaviors that occur against influenza viruses during pandemics.

Epidemiology of influenza viruses from 2009 to 2013 - A sentinel surveillance report from Union territory of Puducherry, India

OBJECTIVE

To report the findings of influenza surveillance programme from Union territory of Puducherry and to document the clinical and epidemiological data of influenza viruses over a five year period from 2009 to 2013.

METHODS

Respiratory samples were collected from patients with influenza-like illness from 2009 to 2013 as part of routine diagnostic and surveillance activity. Detection of pandemic influenza A (H1N1) 2009, influenza A (H3N2) and influenza B was done using Real-time PCR.

RESULTS

Of the total 2247 samples collected from patients with influenza-like illness during the study period 287 (12.7%) and 92 (4.0%) were positive for influenza A (H1N1) 2009 and influenza A (H3N2) respectively. A subset of 557 of these samples were also tested for influenza B and 24 (4.3%) were positive. Significantly higher positivity rate for both viruses was observed in adults when compared with children. The peak positivity of influenza A (H1N1) 2009 was observed in 2009 followed by 2012, while that of influenza A (H3N2) was more uniformly distributed with the exception of 2012. Overall mortality rate due to influenza A (H1N1) 2009 was 7.6% while it was 1% for influenza A (H3N2). Each year influenza-like illness and influenza virus activity coincided with period of high rainfall and low temperature except in the first half of 2012.

CONCLUSIONS

As the sole referral laboratory in this region, the data provides a comprehensive picture of influenza activity. This information will be useful in future planning of the vaccine schedule and influenza pandemic preparedness.

A comparison of H1N1 influenza among pediatric inpatients in the pandemic and post pandemic era

BACKGROUND

The novel influenza A H1N1 (A[H1N1]pdm09) strain emerged in 2009, contributing to significant morbidity and mortality. It is not known whether illness associated with A(H1N1) pdm09 in the post-pandemic era exhibits a similar disease profile.

OBJECTIVE

The objectives of this study were to compare the burden of disease of A(H1N1) pdm09 influenza from the 2009 pandemic year to the post-pandemic years (2010-2014), and to explore potential reasons for any differences.

STUDY DESIGN

We conducted a retrospective cohort study of inpatients admitted to Children's Hospital Colorado with a positive respiratory specimen for influenza from May-December, 2009 and December, 2010-April, 2014. Univariate and multivariate analyses were conducted to compare the demographics and clinical characteristics of patients with H1N1 during the two periods.

RESULTS

There were 388 inpatients with influenza A(H1N1) pdm09 in 2009, and 117 during the post-pandemic years. Ninety-four percent of all H1N1 during the post-pandemic era was observed during the 2013-2014 influenza season. Patients with A(H1N1) pdm09 during the post-pandemic year were less likely to have an underlying medical condition (P<0.01). Patients admitted to the ICU during the post-pandemic year had a lower median age (5 vs 8 years, P=0.01) and a lower proportion of patients were intubated, had mental status changes, and ARDS compared with the pandemic years, (P<0.01 for all), with decreased mortality (P=0.02).

CONCLUSION

Patients with influenza A(H1N1) pdm09 during the post-pandemic years appeared to have less severe disease than patients with A(H1N1) pdm09 during the pandemic year. The reasons for this difference are likely multifactorial.

Shikimic acid, a base compound for the formulation of swine/avian flu drug: statistical optimization, fed-batch and scale up studies along with its application as an antibacterial agent

The sudden outbreak of swine flu has increased the global demand of shikimic acid which is an industrially interesting compound, as it is used as a key starting material for the synthesis of a neuraminidase inhibitor Tamiflu(®), for the treatment of antiviral infections such as swine flu. Statistical optimization and evaluation of medium components for the production of shikimic acid by Citrobacter freundii is addressed in the present investigation. Plackett-Burman design was applied for the screening of the most significant variables affecting shikimic acid production, where glucose, asparagine, KH2PO4, CaCO3 and agitation rate were the most significant factors. Response surface methodology was also employed to study the interaction among the most significant variables through which shikimic acid production increased to 12.76 g/L. Further, fed-batch studies resulted in the production of 22.32 g/L of shikimic acid. The scalability of the process was also confirmed by running 14 L bioreactor (7.5 L production medium) where 20.12 g/L of shikimic acid was produced. In addition the antibacterial activity of the shikimic acid produced was analysed against four Gram positive and four Gram negative bacteria and it was found to have a greater inhibition effect against the Gram negative bacteria.

Influenza polymerase encoding mRNAs utilize atypical mRNA nuclear export

BACKGROUND

Influenza is a segmented negative strand RNA virus. Each RNA segment is encapsulated by influenza nucleoprotein and bound by the viral RNA dependent RNA polymerase (RdRP) to form viral ribonucleoproteins responsible for RNA synthesis in the nucleus of the host cell. Influenza transcription results in spliced mRNAs (M2 and NS2), intron-containing mRNAs (M1 and NS1), and intron-less mRNAs (HA, NA, NP, PB1, PB2, and PA), all of which undergo nuclear export into the cytoplasm for translation. Most cellular mRNA nuclear export is Nxf1-mediated, while select mRNAs utilize Crm1.

METHODS

Here we inhibited Nxf1 and Crm1 nuclear export prior to infection with influenza A/Udorn/307/1972(H3N2) virus and analyzed influenza intron-less mRNAs using cellular fractionation and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We examined direct interaction between Nxf1 and influenza intron-less mRNAs using immuno purification of Nxf1 and RT-PCR of associated RNA.

RESULTS

Inhibition of Nxf1 resulted in less influenza intron-less mRNA export into the cytoplasm for HA and NA influenza mRNAs in both human embryonic kidney cell line (293 T) and human lung adenocarcinoma epithelial cell line (A549). However, in 293 T cells no change was observed for mRNAs encoding the components of the viral ribonucleoproteins; NP, PA, PB1, and PB2, while in A549 cells, only PA, PB1, and PB2 mRNAs, encoding the RdRP, remained unaffected; NP mRNA was reduced in the cytoplasm. In A549 cells NP, NA, HA, mRNAs were found associated with Nxf1 but PA, PB1, and PB2 mRNAs were not. Crm1 inhibition also resulted in no significant difference in PA, PB1, and PB2 mRNA nuclear export.

CONCLUSIONS

These results further confirm Nxf1-mediated nuclear export is functional during the influenza life cycle and hijacked for select influenza mRNA nuclear export. We reveal a cell type difference for Nxf1-mediated nuclear export of influenza NP mRNA, a reminder that cell type can influence molecular mechanisms. Importantly, we conclude that in both A549 and 293 T cells, PA, PB1, and PB2 mRNA nuclear export is Nxf1 and Crm1 independent. Our data support the hypothesis that PA, PB1, and PB2 mRNAs, encoding the influenza RdRP, utilize atypical mRNA nuclear export.

Pandemic influenza plans in residential care facilities

OBJECTIVES

To identify characteristics of residential care facilities (RCFs) associated with having a pandemic influenza plan.

DESIGN

Nationally representative, cross-sectional survey.

SETTING

RCFs in the United States.

PARTICIPANTS

Participating facilities in the 2010 National Survey of RCFs (N = 2,294), representing 31,030 assisted living facilities and personal care homes.

MEASUREMENTS

Facility-level characteristics associated with a pandemic influenza plan, including general organization descriptors, staffing, resident services, and immunization practices.

RESULTS

Forty-five percent (95% confidence interval (CI) = 43-47%) had a pandemic plan, 14% (95% CI = 13-16%) had a plan in preparation, and 41% (95% CI = 38-43%) had no plan. In the multivariable model, organization characteristics, staffing, and immunization practices were independently associated with the presence of a pandemic preparedness plan. Organization characteristics were larger size (extra large, OR = 3.27, 95% CI = 1.96-5.46; large, OR = 2.60, 95% CI = 1.81-3.75; medium, OR = 1.66, 95% CI = 1.21-2.27 vs small), not-for-profit status (OR = 1.65, 95% CI = 1.31-2.09 vs for profit), and chain affiliation (OR = 1.65, 95% CI = 1.31-2.09 vs nonaffiliated). Staffing characteristics included number of registered nurse hours (<15 minutes, OR = 1.36, 95% CI = 1.07-1.74 vs no hours), any licensed practical nurse hours (OR = 1.47, 95% CI = 1.08-1.99 vs no hours), and at least 75 hours of required training for aides (OR = 1.34, 95% CI = 1.05-1.71 vs <75 hours). RCFs with high staff influenza vaccination rates (81-100%, OR = 2.12, 95% CI = 1.27-3.53 vs 0% vaccinated) were also more likely to have a pandemic plan.

CONCLUSION

A majority of RCFs lacked a pandemic influenza plan. These facilities were smaller, for-profit, non-chain-affiliated RCFs and had lower staff vaccination rates. These characteristics may help target facilities that need to develop plans to handle a pandemic, or other disasters.

Preparing ICUs for pandemics

PURPOSE OF REVIEW

Influenza pandemics occur intermittently and represent an existential global infectious diseases threat. The purpose of this review is to describe clinical and research preparedness for future pandemics.

RECENT FINDINGS

Pandemic influenza typically results in large numbers of individuals with life-threatening pneumonia requiring treatment in ICUs. Clinical preparedness of ICUs relates to planning to provide increased 'surge' capacity to meet increased demand and requires consideration of staffing, equipment and consumables, bed-space availability and management systems. Research preparedness is also necessary, as timely clinical research has the potential to change the trajectory of a pandemic. The clinical research response during the 2009 H1N1 influenza pandemic was suboptimal.

SUMMARY

Better planning is necessary to optimize both clinical and research responses to future pandemics.

Simultaneous discrimination and detection of influenza A(H1N1)pdm09 and seasonal influenza A viruses using a rapid immunogold biosensor

A rapid immunogold biosensor for the simultaneous discrimination of influenza A(H1N1)pdm09 and seasonal influenza A viruses was developed successfully. Monoclonal antibodies (mAbs) that were specific for the hemagglutinin protein of the A(H1N1)pdm09 virus were produced, and the best mAb pairs were selected. Using an mAb that was specific for the influenza A nucleoprotein, a rapid immunogold biosensor for the discrimination and detection of A(H1N1)pdm09/seasonal influenza viruses was developed. When tested with 72 virus isolates, the system achieved 100 % detection of the A(H1N1)pdm09 virus without cross-reactivity against seasonal influenza A (H1, H3 subtypes) and B viruses, parainfluenza viruses, respiratory syncytial viruses, and adenoviruses. The detection limits for A(H1N1)pdm09 and seasonal strains were 5 × 10(2)-7.5 × 10(3) and 1 × 10(3)-7.5 × 10(5) TCID50/mL, respectively. When tested with 49 clinical specimens, the specificity was high (100 %). The sensitivity for the detection of A(H1N1)pdm09 and seasonal strains was 90 % and 100 %, respectively, which correlated with the results of real-time reverse transcription polymerase chain reaction as a reference method. The ability of the system to detect and discriminate the A(H1N1)pdm09 strain from the seasonal strains suggests that this method may be beneficial for investigation of outbreaks and diagnostic applications. Furthermore, this method might be a useful platform for developing a rapid diagnostic system for the simultaneous discrimination of other influenza virus subtypes during future outbreaks.

Hospital-based influenza surveillance in Korea: hospital-based influenza morbidity and mortality study group

Influenza epidemics occur annually with variations in size and severity. Hospital-based Influenza Morbidity & Mortality was established to monitor influenza epidemics and their severity, which is composed of two surveillance systems: emergency room-based and inpatient-based surveillance. Regarding emergency room-based surveillance, influenza-like illness index (influenza-like illness cases per 1,000 emergency room-visiting subjects), number of laboratory-confirmed cases and the distribution of influenza types were estimated weekly. Inpatient-based surveillance included monitoring for hospitalization, complications, and mortality. The emergency room influenza-like illness index correlated well with the number of laboratory-confirmed influenza cases, and showed a bimodal peak at Week 4 (179.2/1,000 emergency room visits) and Weeks 13-14 (169.6/1,000 emergency room visits) of 2012. Influenza A was the predominant strain during the first epidemic peak, while influenza B was isolated exclusively during the second peak. In 2011-2012 season, the mean admission rate of emergency room-visiting patients with influenza-like illness was 16.3% without any increase over the epidemic period. Among the hospitalized patients with influenza, 33.6% (41 out of 122 patients) were accompanied by complications, and pneumonia (28.7%, 35 out of 122 patients) was the most common. Most fatal cases were caused by influenza A (96.2%) after the first epidemic peak. In conclusion, Hospital-based Influenza Morbidity & Mortality was effective for monitoring the trends in circulating influenza activity concurrently with its severity. In the 2011-2012 season, the influenza epidemic persisted for a ≥ 5-month period, with a bimodal peak of influenza A and B in sequence. Overall, influenza A was more severe than influenza B.

Influenza-like illness in acute myocardial infarction patients during the winter wave of the influenza A H1N1 pandemic in London: a case-control study

OBJECTIVE

To investigate recent respiratory and influenza-like illnesses (ILIs) in acute myocardial infarction patients compared with patients hospitalised for acute non-vascular surgical conditions during the second wave of the 2009 influenza A H1N1 pandemic.

DESIGN

Case-control study.

SETTING

Coronary care unit, acute cardiology and acute surgical admission wards in a major teaching hospital in London, UK.

PARTICIPANTS

134 participants (70 cases and 64 controls) aged ≥40 years hospitalised for acute myocardial infarction and acute surgical conditions between 21 September 2009 and 28 February 2010, frequency-matched for gender, 5-year age-band and admission week. PRIMARY EXPOSURE: ILI (defined as feeling feverish with either a cough or sore throat) within the last month. SECONDARY EXPOSURES: Acute respiratory illness within the last month not meeting ILI criteria; nasopharyngeal and throat swab positive for influenza virus.

RESULTS

29 of 134 (21.6%) participants reported respiratory illness within the last month, of whom 13 (9.7%) had illnesses meeting ILI criteria. The most frequently reported category for timing of respiratory symptom onset was 8-14 days before admission (31% of illnesses). Cases were more likely than controls to report ILI-adjusted OR 3.17 (95% CI 0.61 to 16.47)-as well as other key respiratory symptoms, and were less likely to have received influenza vaccination-adjusted OR 0.46 (95% CI 0.19 to 1.12)-although the differences were not statistically significant. No swabs were positive for influenza virus.

CONCLUSIONS

Point estimates suggested that recent ILI was more common in patients hospitalised with acute myocardial infarction than with acute surgical conditions during the second wave of the influenza A H1N1 pandemic, and influenza vaccination was associated with cardioprotection, although the findings were not statistically significant. The study was underpowered, partly because the age groups typically affected by acute myocardial infarction had low rates of infection with the pandemic influenza strain compared with seasonal influenza.

Expanding horizons of shikimic acid. Recent progresses in production and its endless frontiers in application and market trends

Shikimic acid is an industrially important chiral compound used as a key ingredient in formulation of drug Oseltamivir phosphate (Tamiflu) for the treatment of swine/avian flu. The high cost and limited availability of shikimic acid isolated from plants has detained the use of this valuable building block of the drug. It is a versatile compound having many characteristic properties for many synthetic reactions particularly in pharmaceuticals and cosmetic industries. By virtue of being a natural product, the relevant biochemical pathway in microorganisms can be harnessed into fermentation processes to produce shikimic acid. This is an excellent alternative for the sustainable and efficient production of shikimic acid over the tedious and cumbersome process of plant based extraction methods. Various strategies of shikimic acid production are reviewed and an account of comparison of their challenges, promises and restraint is presented. Furthermore, present review attempts to focus on the market trend of shikimic acid due to its high demand with particular emphasis laid on the pandemics of swine flu. This review not only covers the recent advances in shikimic acid production but also highlights the versatile applications and its market scenario. The concluding remarks and its potential as a commercial bulk chemical are discussed in the light of current research.

Pandemism of swine flu and its prospective drug therapy

Swine flu is a respiratory disease caused by influenza A H1N1 virus. The current pandemic of swine flu is most probably due to a mutation-more specifically, a re-assortment of four known strains of influenza A virus subtype H1N1. Antigenic variation of influenza viruses while circulating in the population is an important factor leading to difficulties in controlling influenza by vaccination. Due to the global effect of swine flu and its effect on humans, extensive investigations are being undertaken. In this context, Tamiflu is the only available drug used in the prophylaxis of this disease and is made from the compound shikimic acid. Due to the sudden increase in the demand of shikimic acid, its price has increased greatly. Thus, it is necessary to find an alternative approach for the treatment of swine flu. This review presents the overall information of swine flu, beginning from its emergence to the prevention and treatment of the disease, with a major emphasis on the alternative approach (bacterial fermentation process) for the treatment of swine flu. The alternative approach for the treatment of swine flu includes the production of shikimic acid from a fermentation process and it can be produced in large quantities without any time limitations.

Advances and future challenges in recombinant adenoviral vectored H5N1 influenza vaccines

The emergence of a highly pathogenic avian influenza virus H5N1 has increased the potential for a new pandemic to occur. This event highlights the necessity for developing a new generation of influenza vaccines to counteract influenza disease. These vaccines must be manufactured for mass immunization of humans in a timely manner. Poultry should be included in this policy, since persistent infected flocks are the major source of avian influenza for human infections. Recombinant adenoviral vectored H5N1 vaccines are an attractive alternative to the currently licensed influenza vaccines. This class of vaccines induces a broadly protective immunity against antigenically distinct H5N1, can be manufactured rapidly, and may allow mass immunization of human and poultry. Recombinant adenoviral vectors derived from both human and non-human adenoviruses are currently being investigated and appear promising both in nonclinical and clinical studies. This review will highlight the current status of various adenoviral vectored H5N1 vaccines and will outline novel approaches for the future.

Protective effects of long pentraxin PTX3 on lung injury in a severe acute respiratory syndrome model in mice

The outbreak of severe acute respiratory syndrome (SARS) in 2003 reinforces the potential of lethal pandemics of respiratory viral infections. The underlying mechanisms of SARS are still largely undefined. Long pentraxin PTX3, a humoral mediator of innate immunity, has been reported to have anti-viral effects. We examined the role of PTX3 in coronavirus murine hepatitis virus strain 1 (MHV-1)-induced acute lung injury, a previously reported animal model for SARS. PTX3-deficient mice (129/SvEv/C57BL6/J) and their wild-type (WT) littermates were intranasally infected MHV-1. These mice were also treated with recombinant PTX3. Effects of PTX3 on viral binding and infectivity were determined in vitro. Cytokine expression, severity of lung injury, leukocyte infiltration and inflammatory responses were examined in vivo. In PTX3 WT mice, MHV-1 induced PTX3 expression in the lung and serum in a time-dependent manner. MHV-1 infection led to acute lung injury with greater severity in PTX3-deficient mice than that in WT mice. PTX3 deficiency enhanced early infiltration of neutrophils and macrophages in the lung. PTX3 bound to MHV-1 and MHV-3 and reduced MHV-1 infectivity in vitro. Administration of recombinant PTX3 significantly accelerated viral clearance in the lung, attenuated MHV-1-induced lung injury, and reduced early neutrophil influx and elevation of inflammatory mediators in the lung. Results from this study indicate a protective role of PTX3 in coronaviral infection-induced acute lung injury.

Use of extracorporeal respiratory support during pregnancy: a case report and literature review

We describe the case of a 25 year-old woman at 27 weeks of gestation who was admitted to our intensive care unit (ICU) for acute respiratory distress syndrome (ARDS) caused by pandemic 2009 H1N1 influenza A. She presented with septic shock and refractory hypoxemia unresponsive to rescue therapies such as recruitment maneuvers, prone positioning, and nitric oxide inhalation. Extracorporeal membrane oxygenation (ECMO) for respiratory support was instituted, and the patient's clinical conditions progressively improved: she was extubated after 16 days and discharged from the ICU 3 days later. No fetal complications were observed. At 38 weeks of gestation she gave birth to a healthy baby.

H1N1v at a seroepidemiological glance: is the nightmare over?

When the second wave of pandemic influenza A H1N1v 2009 (H1N1v) emerged in the winter of 2010/2011, public health authorities were afraid of dangerous implications and severe clinical courses again. As further H1N1v waves might appear, achievement of sufficient herd immunity is a matter of urgency. The objective of this study was to determine the seroprevalence of antibodies against H1N1v by hemagglutination-inhibition test (HI) after the second wave. We compared our recent findings with our data obtained after the first pandemic in 2009/2010. Between March and May 2011 we collected serum samples from 600 persons aged 1 to 84 years admitted to University Hospital Frankfurt/Main and analysed the titres of anti-H1N1v by HI. The overall seroprevalence of anti-H1N1v has risen from 36.9% (95% confidence interval (95%CI), 33-41) in unvaccinated persons after the first wave to 57.3% (95%CI, 53.1-61.2) in vaccinated and unvaccinated. The highest rate of seropositivity was detected in the age group of 10-19 years (66%; 95%CI, 55.8-75.2), whereas the lowest was found in the age group 40-59 years (51%; 95%CI, 40.8-61.1). Although seroprevalence has significantly increased, sufficient herd immunity is still not achieved. Therefore, general vaccination programs have to be propagated continuously by public health authorities.

The spread of influenza A(H1N1)pdm09 virus in Madagascar described by a sentinel surveillance network

Background

The influenza A(H1N1)pdm09 virus has been a challenge for public health surveillance systems in all countries. In Antananarivo, the first imported case was reported on August 12, 2009. This work describes the spread of A(H1N1)pdm09 in Madagascar.

Methods

The diffusion of influenza A(H1N1)pdm09 in Madagascar was explored using notification data from a sentinel network. Clinical data were charted to identify peaks at each sentinel site and virological data was used to confirm viral circulation.

Results

From August 1, 2009 to February 28, 2010, 7,427 patients with influenza-like illness were reported. Most patients were aged 7 to 14 years. Laboratory tests confirmed infection with A(H1N1)pdm09 in 237 (33.2%) of 750 specimens. The incidence of patients differed between regions. By determining the epidemic peaks we traced the diffusion of the epidemic through locations and time in Madagascar. The first peak was detected during the epidemiological week 47-2009 in Antananarivo and the last one occurred in week 07-2010 in Tsiroanomandidy.

Conclusion

Sentinel surveillance data can be used for describing epidemic trends, facilitating the development of interventions at the local level to mitigate disease spread and impact.

Pandemic 2009 H1N1 virus infection in children and adults: A cohort study at a single hospital throughout the epidemic

BACKGROUND

In 2009, there was an influenza pandemic in South Korea. The aim of this study was to evaluate the epidemiological, clinical and laboratory characteristics of this infection in children and adults.

METHODS

We evaluated the epidemiologic characteristics of patients infected with the 2009 H1N1 influenza A virus (4,463 patients, age range from 2 mo to 86 y), and the clinical and laboratory findings of 373 inpatients (80/217 children, ≤ 15 y, had pneumonia and 36/156 adults, > 16 y, had pneumonia) in a single hospital during the epidemic.

RESULTS

The majority of infected patients (94%) were less than 40 y, and greater than 90% of cases occurred during a two-month period. The rates of admission and pneumonia were 8.4% (373/4,463) and 2.5% (116/4,463), respectively. The rates of admission and pneumonia, total duration of fever, the frequency of underlying diseases, and the values of C-reactive protein and erythrocyte sedimentation rate tended to increase as age increased; highest rates were found in the ≥ 65 y group. Pneumonia was founded more boys than girls in children, but more female than male in adults. The adult patients with pneumonia had higher leukocyte counts with lower lymphocyte differentials than the group without pneumonia, as shown in children group.

CONCLUSION

Our results suggest that the immunologic reaction to viral insults may be associated with age, sex and underlying diseases, and that unknown herd immunity may affect populations. The patients with underlying diseases, especially in older patients may have immunologic insufficiency that is associated with immunologic consumption by the underlying diseases.

Energy intake and response to infection with influenza

Influenza is a worldwide public health concern, particularly with emerging new strains of influenza to which vaccines are ineffective, limited, or unavailable. In addition, the relationship between adequate nutrition and immune function has been repeatedly demonstrated. Mouse models provide strong evidence that energy extremes, including energy restriction (ER) and diet-induced obesity (DIO), have deleterious effects on the immune response to influenza infection. Both ER and DIO mice demonstrate increased susceptibility and mortality to influenza infection. The effects of ER are more pronounced during innate responses to influenza infection, whereas the effects of DIO are evidenced during innate and adaptive responses to both primary and secondary infection. There are striking similarities between ER and DIO during influenza infection, including impaired natural killer cell function and altered inflammation. Future studies must develop effective nutritional paradigms to offset the effects of these energy extremes on the immune response to an acute infection.

The use of mathematical models to inform influenza pandemic preparedness and response

Influenza pandemics have occurred throughout history and were associated with substantial excess mortality and morbidity. Mathematical models of infectious diseases permit quantitative description of epidemic processes based on the underlying biological mechanisms. Mathematical models have been widely used in the past decade to aid pandemic planning by allowing detailed predictions of the speed of spread of an influenza pandemic and the likely effectiveness of alternative control strategies. During the initial waves of the 2009 influenza pandemic, mathematical models were used to track the spread of the virus, predict the time course of the pandemic and assess the likely impact of large-scale vaccination. While mathematical modeling has made substantial contributions to influenza pandemic preparedness, its use as a realtime tool for pandemic control is currently limited by the lack of essential surveillance information such as serological data. Mathematical modeling provided a useful framework for analyzing and interpreting surveillance data during the 2009 influenza pandemic, for highlighting limitations in existing pandemic surveillance systems, and for guiding how these systems should be strengthened in order to cope with future epidemics of influenza or other emerging infectious diseases.

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.

Monitoring vaccine safety using the Vaccine Safety Datalink: utilizing immunization registries for pandemic influenza

Mass vaccination campaigns during which new vaccines may be administered to many millions of people in a short period of time call for timely and accurate post-licensure surveillance to monitor vaccine safety. To address the need for timely H1N1 influenza vaccine safety information during the 2009-2010 H1N1 influenza pandemic, the Vaccine Safety Datalink (VSD) project assessed the feasibility and potential mechanisms for utilizing data from state and local immunization registries to capture vaccinations that would not otherwise be captured by the data systems of the participating VSD managed care organizations (MCOs). Three of the eight VSD sites were able to capture H1N1 immunization data electronically from the state and local registries, and one site was able to capture the immunizations through a paper-based system; however, the remaining four sites encountered various obstacles that prevented capture of such data. Additional work will be required at these sites to overcome the barriers, which included privacy and confidentiality laws, time constraints brought on by the pandemic, as well as data quality concerns.

Limited prevalence of influenza A/H1N1v antibodies: footprints of the pandemic of 2010

BACKGROUND

The intention of our investigation was to determine the seroprevalence of H1N1v antibodies after a pandemic by the haemagglutination inhibition (HI) test. We included the serum samples of adults who had not received vaccination against H1N1v. By means of serological footprints, the spread of infection can be investigated.

MATERIALS AND METHODS

Between December 2009 and May 2010, we collected 233 serum samples from healthy people aged 1-72 years and analysed the titres of H1N1v antibodies by the use of the HI test.

RESULTS

After the pandemic, a seroprevalence of 36.9% was observed. The highest rate of seropositivity was detected in the age group of 10-19 years (60%) and the lowest rate was found in the age group of 30-39 years (22%). The seroprevalence of H1N1v antibodies in females exceeded the rate of positive men (41.5 vs. 31.8%). Almost 70% of the influenza A/H1N1v infections were passed inapparently.

[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.

Pandemic influenza A/H1N1 virus infection in solid organ transplant recipients: a multicenter study

BACKGROUND

The 2009 novel influenza A/H1N1 virus pandemic did not spare solid organ transplant (SOT) recipients. We aimed to describe the behavior of pandemic influenza infection in a group of SOT recipients in Argentina.

METHODS

Data from 10 transplant (Tx) centers were retrospectively collected for SOT that presented with a respiratory illness compatible with pandemic influenza A infection, between May and September 2009. Cases were defined as suspected, probable, or confirmed according to diagnostic method.

RESULTS

Seventy-seven cases were included. No significant differences in presenting symptoms, pulmonary infiltrates, and graft involvement were found among 35 suspected, 19 probable, and 23 confirmed cases. The 33 ambulatory cases had significantly more sore throat and headache when compared with 34 cases admitted to medical ward (MW) and 10 admitted to intensive care unit (ICU), 9 of whom required ventilatory support. MW and ICU cases had significantly more dyspnea, hypoxemia, pulmonary infiltrates, and graft dysfunction. Time from onset of symptoms to first visit and to treatment was significantly longer in MW and ICU cases (P=0.008). Coinfections were found in six cases. Most cases received oseltamivir for 5 to 10 days. Six patients (7.8%) died from viral infection at a median of 15 days from admission. No differences in outcome were seen related to the transplanted organ, the immunosuppressive regimen, time from Tx, or confirmation of diagnosis.

CONCLUSIONS

Mortality is higher in Tx recipients than in the general population. Poor outcome seems to be related to a delay in the beginning of treatment.

Influenza pandemics

The recent H1N1 pandemic that emerged in 2009 has illustrated how swiftly a new influenza virus can circulate the globe. Here we explain the origins of the 2009 pandemic virus, and other twentieth century pandemics. We also consider the impact of the 2009 pandemic in the human population and the use of vaccines and antiviral drugs. Thankfully this outbreak was much less severe than that associated with Spanish flu in 1918. We describe the viral factors that affect virulence of influenza and speculate on the future course of this virus in humans and animals.

Pandemic 2009 (A)H1N1 influenza (swine flu) — the Manitoba experienceThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process

The pattern of illness associated with the first wave of the pandemic influenza A H1N1 (swine flu) in the spring and early summer of 2009 in regions of the province of Manitoba in Canada was more severe, on a population basis, than any other northern hemisphere jurisdiction outside of Mexico City. Manitoba accounted for 50% of intensive care admissions and 25% of pediatric admissions, but only 6.5% of deaths, attributable to the virus in Canada during the first wave. Activation and use of emergency response protocols embedded within the routine health authority management system and good communication between the diagnostic laboratory, public health, and health care practitioners was effective in coping with the sudden need for hospitalization of large numbers of children and young adults with severe respiratory illness over a short time period. Early treatment with oseltamivir was associated with a shorter duration of hospitalization among children. Intensive education of health care providers, patients, and visitors, along with close monitoring of infection prevention and control practices, were instrumental in preventing both nosocomial and health care worker infections.