A.M. van Loon

Influenza- and respiratory syncytial virus-associated mortality and hospitalisations

The aim of the current study was to estimate influenza- and respiratory syncytial virus (RSV)-associated mortality and hospitalisations, especially the influenza-associated burden among low-risk individuals ≤65u2005yrs old, not yet recommended for influenza vaccination in many European countries. Retrospectively during 1997–2003, Dutch national all-cause mortality and hospital discharge figures and virus surveillance data were used to estimate annual average influenza- and RSV-associated excess mortality and hospitalisation using rate difference methods. Influenza virus active periods were significantly associated with excess mortality among 50–64-yr-olds and the elderly, but not in younger age categories. Influenza-associated hospitalisation was highest and about equal for 0–1-yr-olds and the elderly, and also significant for low-risk adults. Hospitalisation among children was mostly due to respiratory conditions, and among adults cardiovascular complications were frequent. RSV-active periods were associated with excess mortality and hospitalisation among the elderly. The highest RSV-related excess hospitalisation was found in 0–1-yr-olds. Influenza-associated mortality was demonstrated in 50–64-yr-olds. Among low-risk individuals ≤65u2005yrs of age, influenza-associated hospitalisation rates were highest for 0–4-yr-olds, but also significant for 5–64-yr-olds. These data may further support extension of recommendations for influenza vaccination to include younger low-risk persons. The respiratory syncytial virus-associated burden was highest for young children but also substantial for the elderly.

Invasive pneumococcal and meningococcal disease: association with influenza virus and respiratory syncytial virus activity?

Few studies have examined the relationship between viral activity and bacterial invasive disease, considering both influenza virus and respiratory syncytial virus (RSV). This study aimed to assess the potential relationship between invasive pneumococcal disease (IPD), meningococcal disease (MD), and influenza virus and RSV activity in The Netherlands. Correlations were determined between population-based data on IPD and MD during 1997-2003 and influenza virus and RSV surveillance data. Incidence rate ratios of disease during periods of high influenza virus and RSV activity over the peri-seasonal and summer baseline periods were calculated. The analyses comprised 7266 and 3072 cases of IPD and MD. When data from all seasons were included, the occurrence of pneumococcal bacteraemia and MD correlated significantly with influenza virus and RSV activity both in children and adults. Periods of increased influenza virus and RSV activity showed higher rates of pneumococcal bacteraemia in older children and adults than the peri-season period. Rates of MD in children were also higher during periods of increased influenza virus activity; the same appeared true for MD in older children during periods of increased RSV activity. Although no causal relationship may be inferred from these data, they support a role for influenza virus and RSV in the pathogenesis of IPD and MD.

Diagnosis of Enterovirus Infection in the First 2 Months of Life by Real-Time Polymerase Chain Reaction

During summer and fall, enterovirus infections are responsible for a considerable proportion of hospitalizations of young infants. We prospectively studied the incidence of enterovirus infections via real-time polymerase chain reaction (PCR) in blood, feces, and cerebrospinal fluid samples from infants <or=60 days old who had received a clinical diagnosis of sepsis. Forty-five patients were included: 19 were admitted to the pediatric wards of 2 general hospitals, and 26 had been hospitalized since birth in the neonatal intensive care unit (NICU) of a tertiary care hospital. None of the NICU patients developed enteroviral disease. In contrast, an enterovirus was detected in 11 (58%) of the patients admitted to the 2 general hospitals, 10 of whom (53%) showed evidence of systemic infection. Enterovirus infections are an important cause of sepsis in infants admitted to the hospital. Real-time PCR in serum was a rapid and sensitive method for diagnosis of enterovirus infection.

Performance of Different Mono- and Multiplex Nucleic Acid Amplification Tests on a Multipathogen External Quality Assessment Panel

ABSTRACT An external quality assessment (EQA) panel consisting of a total of 48 samples in bronchoalveolar lavage (BAL) fluid or transport medium was prepared in collaboration with Quality Control for Molecular Diagnostics (QCMD) (www.qcmd.org). The panel was used to assess the proficiency of the three laboratories that would be responsible for examining the 6,000 samples to be collected in the GRACE Network of Excellence (www.grace-lrti.org). The main objective was to decide on the best-performing testing approach for the detection of influenza viruses A and B, parainfluenza virus types 1 to 3, respiratory syncytial virus (RSV), human metapneumovirus, coronavirus, rhinovirus, adenovirus, Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila by nucleic acid amplification techniques (NAATs). Two approaches were chosen: (i) laboratories testing samples using their in-house procedures for extraction and amplification and (ii) laboratories using their in-house amplification procedures on centrally extracted samples. Furthermore, three commercially available multiplex NAAT tests—the ResPlex (Qiagen GmbH, Hilden, Germany), RespiFinder plus (PathoFinder, Maastricht, The Netherlands), and RespiFinder Smart 21 (PathoFinder) tests—were evaluated by examination of the same EQA panel by the manufacturer. No large differences among the 3 laboratories were noticed when the performances of the assays developed in-house in combination with the in-house extraction procedures were compared. Also, the extraction procedure (central versus local) had little effect on performance. However, large differences in amplification efficacy were found between the commercially available tests; acceptable results were obtained by using the PathoFinder assays.

Symptoms of influenza virus infection in hospitalized patients

BACKGROUNDnDuring influenza outbreaks, fever and cough are the most accurate symptoms in predicting influenza virus infection in the community.nnnOBJECTIVEnTo determine the usefulness of fever, cough, and other symptoms for diagnosing influenza virus infection in hospitalized patients.nnnDESIGNnProspective cohort study.nnnSETTINGnThree wards (pulmonology, internal medicine and infectious diseases, and geriatrics) of a tertiary care hospital in the Netherlands.nnnPATIENTSnAll patients staying in the wards during peak national influenza activity in the 2005-2006 and 2006-2007 influenza seasons.nnnMETHODSnDuring peak influenza activity, the presence of fever, cough, and/or other symptoms possibly associated with influenza was monitored for all patients, and nose and throat swab samples were taken twice weekly for virologic analysis.nnnRESULTSnOf 264 patients, 23 (9%) tested positive for influenza virus. The positive predictive value of fever and cough for the diagnosis of influenza virus infection was 23% (95% confidence interval, 0%-62%), and the sensitivity was 35% (95% confidence interval, 11%-58%). The combination of symptoms with the highest positive predictive value (40%) was that of cough, chills, and obstructed nose or coryza. The combination of cough and chills or fever had the highest sensitivity (60%). None of the combinations of symptoms had both a positive predictive value and a sensitivity higher than 40%.nnnCONCLUSIONSnBoth the sensitivity and the positive predictive value of fever, cough, and/or other symptoms for the diagnosis of influenza virus infection in hospitalized patients are low. The use of these common symptoms for treatment decisions and infection control management will probably be insufficient to contain a nosocomial outbreak, because many influenza cases will remain unidentified.

HIV-1 drug resistance genotyping quality assessment: Results of the ENVA7 Genotyping Proficiency Programme

BACKGROUNDnDrug-resistance testing plays a critical role in selection of optimal treatment regimens for HIV infected individuals. Laboratories performing testing must implement quality control measures including external quality assessment.nnnOBJECTIVESnThe ENVA7 Programme (2007) was organised by QCMD to assess the performance of laboratories testing for drug-resistance mutations in the HIV-1 Protease and Reverse Transcriptase genes.nnnSTUDY DESIGNnThe ENVA7 panel consisted of 5 lyophilised plasma samples (HIV-1 subtypes B, C and F). The viruses harboured wild type or resistant genotypes at various positions of the PR and RT genes. All IAS-defined resistance-associated codons were scored in comparison to the consensus sequence for each sample using a scoring system developed to allow simple and standardised comparisons between laboratories and/or technologies.nnnRESULTSn111 laboratories from 44 countries participated of which 95 submitted 98 datasets. 36 datasets were generated using ViroSeq (Abbott), 27 using TruGene (Siemens) and 35 using in-house assays.nnnCONCLUSIONSnAll technologies successfully genotyped each of the panel samples, irrespective of the virus subtype. While the assays for genotypic HIV drug-resistance determination have evolved into reliable and technically capable procedures of generating high quality results, variation in the quality of results is still observed between laboratories.

Prolonged shedding of rhinovirus and re-infection in adults with respiratory tract illness

Rhinovirus infections occur frequently throughout life and have been reported in about one-third of asymptomatic cases. The clinical significance of sequential rhinovirus infections remains unclear. To determine the incidence and clinical relevance of sequential rhinovirus detections, nasopharyngeal samples from 2485 adults with acute cough/lower respiratory illness were analysed. Patients were enrolled prospectively by general practitioners from 12 European Union countries during three consecutive years (2007–2010). Nasopharyngeal samples were collected at the initial general practitioner consultation and 28 days thereafter and symptom scores were recorded by patients over that period. Rhinovirus RNA was detected in 444 (18%) out of 2485 visit one samples and in 110 (4.4%) out of 2485 visit two respiratory samples. 21 (5%) of the 444 patients had both samples positive for rhinovirus. Genotyping of both virus detections was successful for 17 (81%) out of 21 of these patients. Prolonged rhinovirus shedding occurred in six (35%) out of 21 and re-infection with a different rhinovirus in 11 (65%) out of 21. Rhinovirus re-infections were significantly associated with chronic obstructive pulmonary disease (p=0.04) and asthma (p=0.02) and appeared to be more severe than prolonged infections. Our findings indicate that in immunocompetent adults rhinovirus re-infections are more common than prolonged infections, and chronic airway comorbidities might predispose to more frequent rhinovirus re-infections. Chronic airway comorbidities might predispose to more frequent rhinovirus re-infections in immunocompetent adults http://ow.ly/vdB3g

A multi-centre pilot proficiency programme to assess the quality of molecular detection of respiratory viruses

n Abstractn n Objectivesn To assess the quality of molecular detection of respiratory viruses in clinical diagnostic laboratories.n n n Study designn Respiratory virus proficiency panels were produced from diluted stocks of respiratory viruses provided and tested by four reference laboratories. The panels consisted of strong positive, positive, low positive and negative samples for influenza viruses A and B, respiratory syncytial virus, parainfluenza viruses 1 and 3, adenovirus serotypes 4 and 7, human rhinovirus serotypes 16, 72 and 90, human coronaviruses OC43 and 229E. The panels were sent to 17 participants; results and information on methodology was collected.n n n Resultsn All laboratories returned results, of which five submitted complete data sets. So, for analysis all results were combined. Samples were correctly identified by participants in 93.75%, 76.75% and 47.03% for the high positive, positive and low positive samples, respectively. One false positive was reported for all data sets (1.1%). The overall score for all assays using different methodologies was 78.8%. Laboratory performance was not dependant on methodology as all in-house methodologies could achieve optimal results, but dependant on careful optimisation and procedures specific to the laboratory.n n n Conclusionsn The first proficiency panel showed that in general all participants performed well. Although, it also highlights areas for improvement for all participants in order to generate robust results for use in clinical diagnostics.n n

Persistent and transient hepatitis B virus (HBV) infections in children born to HBV-infected mothers despite active and passive vaccination.

Summary.u2002 Combined passive and active immunization for newborns very effectively prevents perinatal hepatitis B virus (HBV) infections. In the Netherlands, babies born to hepatitis B surface antigen (HBsAg)‐positive women receive passive immunization with hepatitis B and at least three active HBsAg vaccinations. Serological testing for the presence of HBV markers was offered for all infants born to HBsAg‐positive mothers between January 2003 and July 2007, after completion of their vaccination schedule. About 75% of the infants (nu2003=u20031743) completed their HB‐vaccination schedule and participated in the serologic evaluation. Twelve of them (0.7%) were found to be HBV infected. Furthermore, we identified three older children with high levels of anti‐HBc, anti‐HBs and anti‐HBe, while they were HBsAg and HBV DNA negative. This serologic profile is evidence for a resolved HBV infection. In the group of older children (1.5–5u2003years of age, nu2003=u2003728), about half of the HBV‐infected children (3 of 7) had already cleared their infection at the time of sampling. For a proper evaluation of the efficacy of a new intervention programme to prevent vertical HBV transmission, it is also important to analyse the HBV markers in serum collected when the children are older than 1.5u2003years. In a programmatic setting, all children born to HBV‐infected mothers should be tested not only for the level of anti‐HBs but also for the absence of HBsAg, because 2 of the 12 HBV‐infected children (17%) had a high level of anti‐HBs.

Molecular detection and typing of influenza viruses : Are we ready for an influenza pandemic?

BACKGROUNDnWe cannot predict when an influenza pandemic will occur or which variant of the virus will cause it. Little information is currently available on the ability of laboratories to detect and subtype influenza viruses including the avian influenza viruses.nnnOBJECTIVESnTo assess the ability of laboratories to detect and subtype influenza viruses.nnnSTUDY DESIGNnIn 2006 QCMD distributed an External Quality Assessment panel for the molecular detection and haemagglutinin subtyping of influenza viruses to 87 laboratories in 34 countries Worldwide, which were given 6 weeks to return results. These data were analysed to assess laboratory performance.nnnRESULTSnInfluenza virus positive panel samples were correctly identified by 35-98% of laboratories. The correct haemagglutinin subtype was reported by 32-87% of laboratories that detected the virus: incorrect subtyping results included the reporting of avian influenza viruses as human strains and vice versa. Twelve laboratories reported false positives with some avian influenza viruses reported.nnnCONCLUSIONSnThese data suggest that improvements are needed in the molecular detection of influenza viruses and influenza virus A haemagglutinin subtyping. Only rapid and accurate identification of circulating pandemic influenza virus will ensure that the maximum time is available for intervention.