Surveillance of influenza in Northern Ireland

The influenza season started later than normal, clinical indices began to increase marginally in mid-February, much later than previous seasons, and activity remained very low throughout, with community syndromic indicators not reaching the baseline warning threshold during the season. The peak GP influenza-like illness consultation rates in 2011/12 were the lowest since surveillance began in Northern Ireland in 2000. No one age-group appeared predominantly affected, with low levels of activity in all age groups, however, GP consultation rates increased in both children and adults.Influenza A (H3) was the predominant strain of the virus circulating, with small numbers of the influenza B strain circulating later in the season. Unlike the 2010/11 season when Influenza A (H1N1)2009 strain dominated in Northern Ireland, there were no detections of this subtype in 2011/12; virological activity generally corresponded to clinical activity.There were however, patients with confirmed influenza admitted to Intensive care units, across Northern Ireland during the season. Numbers were low, the average age of these patients increased compared with the previous season and one fatality was reported in this group.The proportion of over 65 year olds who received the 2011/12 seasonal influenza vaccine was 77.0%, and in those in a clinical risk group aged under 65 years was 81.7%, both of these vaccination uptake figures were a slight increase on the previous year. Influenza vaccine uptake in frontline healthcare workers also increased marginally this season to 20.8%, as did the proportion of pregnant women vaccinated during the season.

Abnormal humoral immune response to influenza vaccination in pediatric type-1 human immunodeficiency virus infected patients receiving highly active antiretroviral therapy

Given that highly active antiretroviral therapy (HAART) has been demonstrated useful to restore immune competence in type-1 human immunodeficiency virus (HIV-1)-infected subjects, we evaluated the specific antibody response to influenza vaccine in a cohort of HIV-1-infected children on HAART so as to analyze the quality of this immune response in patients under antiretroviral therapy. Sixteen HIV-1-infected children and 10 HIV-1 seronegative controls were immunized with a commercially available trivalent inactivated influenza vaccine containing the strains A/H1N1, A/H3N2, and B. Serum hemagglutinin inhibition (HI) antibody titers were determined for the three viral strains at the time of vaccination and 1 month later. Immunization induced a significantly increased humoral response against the three influenza virus strains in controls, and only against A/H3N2 in HIV-1-infected children. The comparison of post-vaccination HI titers between HIV-1+ patients and HIV-1 negative controls showed significantly higher HI titers against the three strains in controls. In addition, post vaccination protective HI titers (defined as equal to or higher than 1:40) against the strains A/H3N2 and B were observed in a lower proportion of HIV-1+ children than in controls, while a similar proportion of individuals from each group achieved protective HI titers against the A/H1N1 strain. The CD4+ T cell count, CD4/CD8 T cells ratio, and serum viral load were not affected by influenza virus vaccination when pre- vs post-vaccination values were compared. These findings suggest that despite the fact that HAART is efficient in controlling HIV-1 replication and in increasing CD4+ T cell count in HIV-1-infected children, restoration of immune competence and response to cognate antigens remain incomplete, indicating that additional therapeutic strategies are required to achieve a full reconstitution of immune functions.

The risk of acquiring the new influenza A(H1N1) for Brazilian travelers to Chile, Argentina and the USA

We estimate the risk of acquiring the new influenza A(H1N1) for Brazilian travelers to Chile, Argentina and the USA. This is done by a mathematical model that quantifies the intensity of transmission of the new virus in those countries and the probability that one individual has of acquiring the influenza depending on the date of arrival and time spent in the area. The maximum estimated risk reached 7.5 cases per 10,000 visitors to Chile, 17 cases per 10,000 travelers to Argentina and 23 cases per 10,000 travelers to the USA. The estimated number of imported cases until 27 July is 57 ± 9 from Chile, 136 ± 27 from the USA and 301 ± 21 from Argentina, which are in accord with the official figures. Estimating the number of imported cases was particularly important for the moment of the disease introduction into this country, but it will certainly be important again as a tool to calculate the number of future imported cases from northern countries in our next inter-epidemic season, were imported cases can constitute again the majority of the new influenza burden to the Brazilian health services.

Molecular findings from influenza A(H1N1)pdm09 detected in patients from a Brazilian equatorial region during the pandemic period

After the World Health Organization officially declared the end of the first pandemic of the XXI century in August 2010, the influenza A(H1N1)pdm09 virus has been disseminated in the human population. In spite of its sustained circulation, very little on phylogenetic data or oseltamivir (OST) resistance is available for the virus in equatorial regions of South America. In order to shed more light on this topic, we analysed the haemagglutinin (HA) and neuraminidase (NA) genes of influenza A(H1N1)pdm09 positive samples collected during the pandemic period in the Pernambuco (PE), a northeastern Brazilian state. Complete HA sequences were compared and amino acid changes were related to clinical outcome. In addition, the H275Y substitution in NA, associated with OST resistance, was investigated by pyrosequencing. Samples from PE were grouped in phylogenetic clades 6 and 7, being clustered together with sequences from South and Southeast Brazil. The D222N/G HA gene mutation, associated with severity, was found in one deceased patient that was pregnant. Additionally, the HA mutation K308E, which appeared in Brazil in 2010 and was only detected worldwide the following year, was identified in samples from hospitalised cases. The resistance marker H275Y was not identified in samples tested. However, broader studies are needed to establish the real frequency of resistance in this Brazilian region.

Influenza A H1N1/2009 Infection in Pediatric Solid Organ Transplant Recipients

The aim of this study was to describe the clinical characteristics of pandemic influenza A H1N1 infection. A retrospective study was performed in pediatric patients with solid organ transplantation and confirmed influenza A H1N1/2009 infection from June to December 2009, diagnosed in two Spanish teaching. Forty-nine patients were included. Pneumonia was diagnosed in 4 patients (8.2%), and 3 of them required respiratory support. There were no related deaths. Antiviral treatment within 48 hours was associated with a lower likelihood of pneumonia (0/38, 0%) than treatment started after 48 hours (4/11, 36.3%) (p&0.01).

Humoral Response to the Influenza A H1N1/09 Monovalent AS03-Adjuvanted Vaccine in Immunocompromised Patients.

Background. Few data are available regarding the immunogenicity and safety of the pandemic influenza vaccine in immunocompromised patients. We evaluated the humoral response to the influenza A H1N1/09 vaccine in solid-organ transplant (SOT) recipients, in patients with human immunodeficiency virus (HIV) infection, and in healthy individuals. Methods. Patients scheduled to receive the pandemic influenza vaccine were invited to participate. All participants received the influenza A H1N1/09 AS03-adjuvanted vaccine containing 3.75 μg of hemagglutinin. SOT recipients and HIV-infected patients received 2 doses at 3-week intervals, whereas control subjects received 1 dose. Blood samples were taken at day 0, day 21, and day 49 after vaccination. Antibody responses were measured with the hemagglutination inhibition assay (HIA) and a microneutralization assay. Results. Twenty-nine SOT recipients, 30 HIV-infected patients, and 30 healthy individuals were included in the study. Seroconversion measured by HIA was observed in 15 (52%) of 29 SOT recipients both at day 21 and day 49; in 23 (77%) of 30 at day 21 and 26 (87%) of 30 at day 49 in HIV-infected patients, and in 20 (67%) of 30 at day 21 and in 23 (77%) of 30 at day 49 in control subjects (P = .12 at day 21 and P = .009 at day 49, between groups). Geometric means of antibody titers were not significantly different between groups at day 21 or at day 49. Conclusions. Influenza A H1N1/09 vaccine elicited a similar antibody response in HIV-infected individuals and in control subjects, whereas SOT recipients had an overall lower response. A second dose of the vaccine only moderately improved vaccine immunogenicity in HIV-infected patients.

Novel Influenza A (H1N1) Fact Sheet, 2009

The novel flu virus, that is currently circulating in the U.S. and other parts of the world, is a unique combination of swine and human flu viruses. This virus is transmitted from person to person, not from pigs to humans. None of the current cases had exposure to swine.

General Use of Face-Masks and Respirators to Prevent Novel Influenza A (H1N1, May 1, 2009

During this outbreak of swine influenza, many people have questions regarding the best way to protect themselves from becoming ill with the virus and, if you are ill, how to prevent spread of the disease to others.

Novel Influenza A (H1N1) Fact Sheet: General Public, May 1, 2009

What is novel influenza? The novel flu virus, that is currently circulating in the U.S. and other parts of the world, is a unique combination of swine and human flu viruses. This virus is transmitted from person to person, not from pigs to humans. None of the current cases had exposure to swine.

Computed tomography findings in patients with H1N1 influenza A infection

The present study aimed to review high resolution computed tomography findings in patients with H1N1 influenza A infection. The most common tomographic findings include ground-glass opacities, areas of consolidation or a combination of both patterns. Some patients may also present bronchial wall thickening, airspace nodules, crazy-paving pattern, perilobular opacity, air trapping and findings related to organizing pneumonia. These abnormalities are frequently bilateral, with subpleural distribution. Despite their nonspecificity, it is important to recognize the main tomographic findings in patients affected by H1N1 virus in order to include this possibility in the differential diagnosis, characterize complications and contribute in the follow-up, particularly in cases of severe disease.

Étude sur les déterminants psychosociaux de la vaccination contre le virus A(H1N1) auprès des parents d’enfants qui fréquentent des services de garde éducatifs de Montréal

Introduction En juin 2009, l’Organisation Mondiale de la Santé (OMS) a déclaré l’état de pandémie pour le nouveau virus influenza A(H1N1). Malgré les recommandations des autorités de santé publique, lors de la mise en place de la campagne de vaccination de masse au Québec contre ce virus pandémique, certains groupes de la population ont été plus enclins à être vaccinés que d’autres groupes. Ceci souligne l’importance des déterminants psychosociaux du comportement humain, sujet qui a donné cadre à notre étude. Objectifs Le but de cette étude a été de documenter les attitudes, les connaissances et les influences sociales des parents dont les enfants fréquentent des services de garde éducatifs (SGE) vis-à-vis la vaccination contre la pandémie ainsi que la couverture vaccinale. Méthodologie Un questionnaire auto-administré et anonyme basé sur la théorie des comportements interpersonnels de Triandis a été distribué aux parents d’enfants âgés de 0-59 mois de neuf centres de la petite enfance sur l’île de Montréal. Résultats Le taux de réponse de l’enquête a été de 32,0% (N=185). Le taux de vaccination des enfants s’est retrouvé à 83,4%; ceci représente une couverture plus élevée que la moyenne régionale et nationale. Toutefois, à une question sur l’intention des parents face à une autre pandémie, seuls 46% des parents feraient vacciner leur enfant. Les facteurs les plus significatifs associés à la vaccination de leur enfant ont été les croyances personnelles positives, de bonnes habitudes vaccinales et l’influence des média, tous mesurés par plusieurs indicateurs (RC respectifs de 7,7, 3,1 et 4,2, p<0,05). Conclusion Pour la grippe A(H1N1), plusieurs facteurs contextuels ont joué en faveur des taux de vaccination acceptables chez les enfants. Toutefois, la mise en place d’une campagne de la vaccination par les instances gouvernementales et de santé publique en utilisant divers média pourraient contribuer à un taux de vaccination encore plus élevé en cas d’épidémie ou de pandémie.

Transcriptional approach to study porcine tracheal epithelial cells individually or dually infected with swine influenza virus and Streptococcus suis

Background: Swine influenza is a highly contagious viral infection in pigs affecting the respiratory tract that can have significant economic impacts. Streptococcus suis serotype 2 is one of the most important post-weaning bacterial pathogens in swine causing different infections, including pneumonia. Both pathogens are important contributors to the porcine respiratory disease complex. Outbreaks of swine influenza virus with a significant level of co-infections due to S. suis have lately been reported. In order to analyze, for the first time, the transcriptional host response of swine tracheal epithelial (NPTr) cells to H1N1 swine influenza virus (swH1N1) infection, S. suis serotype 2 infection and a dual infection, we carried out a comprehensive gene expression profiling using a microarray approach. Results: Gene clustering showed that the swH1N1 and swH1N1/S. suis infections modified the expression of genes in a similar manner. Additionally, infection of NPTr cells by S. suis alone resulted in fewer differentially expressed genes compared to mock-infected cells. However, some important genes coding for inflammatory mediators such as chemokines, interleukins, cell adhesion molecules, and eicosanoids were significantly upregulated in the presence of both pathogens compared to infection with each pathogen individually. This synergy may be the consequence, at least in part, of an increased bacterial adhesion/invasion of epithelial cells previously infected by swH1N1, as recently reported. Conclusion: Influenza virus would replicate in the respiratory epithelium and induce an inflammatory infiltrate comprised of mononuclear cells and neutrophils. In a co-infection situation, although these cells would be unable to phagocyte and kill S. suis, they are highly activated by this pathogen. S. suis is not considered a primary pulmonary pathogen, but an exacerbated production of proinflammatory mediators during a co-infection with influenza virus may be important in the pathogenesis and clinical outcome of S. suis-induced respiratory diseases.

Capsular sialic acid of Streptococcus suis serotype 2 binds to swine influenza virus and enhances bacterial interactions with virus-infected tracheal epithelial cells.

Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model.

Mutations in H5N1 influenza virus hemagglutinin that confer binding to human tracheal airway epithelium

The emergence in 2009 of a swine-origin H1N1 influenza virus as the first pandemic of the 21st Century is a timely reminder of the international public health impact of influenza viruses, even those associated with mild disease. The widespread distribution of highly pathogenic H5N1 influenza virus in the avian population has spawned concern that it may give rise to a human influenza pandemic. The mortality rate associated with occasional human infection by H5N1 virus approximates 60%, suggesting that an H5N1 pandemic would be devastating to global health and economy. To date, the H5N1 virus has not acquired the propensity to transmit efficiently between humans. The reasons behind this are unclear, especially given the high mutation rate associated with influenza virus replication. Here we used a panel of recombinant H5 hemagglutinin (HA) variants to demonstrate the potential for H5 HA to bind human airway epithelium, the predominant target tissue for influenza virus infection and spread. While parental H5 HA exhibited limited binding to human tracheal epithelium, introduction of selected mutations converted the binding profile to that of a current human influenza strain HA. Strikingly, these amino-acid changes required multiple simultaneous mutations in the genomes of naturally occurring H5 isolates. Moreover, H5 HAs bearing intermediate sequences failed to bind airway tissues and likely represent mutations that are an evolutionary "dead end." We conclude that, although genetic changes that adapt H5 to human airways can be demonstrated, they may not readily arise during natural virus replication. This genetic barrier limits the likelihood that current H5 viruses will originate a human pandemic.

Attenuating mutations in the influenza virus genome which may increase the safety of vaccine production

Influenza virus epidemics occur on an annual basis and cause severe disease in the very young and old. The vaccine administered to high-risk groups is generated by amplifying reassortant viruses, with chronologically relevant viral surface antigens, in eggs. Every 20 years or so, influenza pandemics occur causing widespread fatality in all age groups. These viruses display novel viral surface antigens acquired from a zoonotic source, and vaccination against them poses new issues since production of large amounts of a respiratory virus containing novel surface antigens could be dangerous for those involved in manufacture. To minimise risks, it is advisable to use a virus whose genetic backbone is highly attenuated in man. Traditionally, the A/PR/8/34 strain of virus is used, however, the genetic basis of its attenuation is unclear. Cold-adapted (CA) strains of the influenza virus are all based on the H2N2 subtype, itself a virus with pandemic potential, and again the genetic basis of temperature sensitivity is not yet established. Reverse genetics technology allows us to engineer designer influenza viruses to order. Using this technology, we have been investigating mutations in several different gene segments to effectively attenuate potential vaccine strains allowing the safe production of vaccine to protect against the next pandemic. (C) 2003 Elsevier B.V. All rights reserved.