Peeters, M.

Profiling of Humoral Response to Influenza A(H1N1)pdm09 Infection and Vaccination Measured by a Protein Microarray in Persons with and without History of Seasonal Vaccination (Article)

2013-01-30T00:00:00Z

Background: The influence of prior seasonal influenza vaccination on the antibody response produced by natural infection or vaccination is not well understood. Methods: We compared the profiles of antibody responses of 32 naturally infected subjects and 98 subjects vaccinated with a 2009 influenza A(H1N1) monovalent MF59-adjuvanted vaccine (Focetria®, Novartis), with and without a history of seasonal influenza vaccination. Antibodies were measured by hemagglutination inhibition (HI) assay for influenza A(H1N1)pdm09 and by protein microarray (PA) using the HA1 subunit for seven recent and historic H1, H2 and H3 influenza viruses, and three avian influenza viruses. Serum samples for the infection group were taken at the moment of collection of the diagnostic sample, 10 days and 30 days after onset of influenza symptoms. For the vaccination group, samples were drawn at baseline, 3 weeks after the first vaccination and 5 weeks after the second vaccination. Results: We showed that subjects with a history of seasonal vaccination generally exhibited higher baseline titers for the various HA1 antigens than subjects without a seasonal vaccination history. Infection and pandemic influenza vaccination responses in persons with a history of seasonal vaccination were skewed towards historic antigens. Conclusions: Seasonal vaccination is of significant influence on the antibody response to subsequent infection and vaccination, and further research is needed to understand the effect of annual vaccination on protective immunity.

Immunogenicity, boostability, and sustainability of the immune response after vaccination against influenza A virus (H1N1) 2009 in a healthy population (Article)

2011-09-01T00:00:00Z

The emergence of a new influenza A virus (H1N1) variant in 2009 led to a worldwide vaccination program, which was prepared in a relatively short period of time. This study investigated the humoral immunity against this virus before and after vaccination with a 2009 influenza A virus (H1N1) monovalent MF59-adjuvanted vaccine, as well as the persistence of vaccine-induced antibodies. Our prospective longitudinal study included 498 health care workers (mean age, 43 years; median age, 44 years). Most (89%) had never or only occasionally received a seasonal influenza virus vaccine, and 11% were vaccinated annually (on average, for >10 years). Antibody titers were determined by a hemagglutination inhibition (HI) assay at baseline, 3 weeks after the first vaccination, and 5 weeks and 7 months after the second vaccination. Four hundred thirty-five persons received two doses of the 2009 vaccine. After the first dose, 79.5% developed a HI titer of ≥40. This percentage increased to 83.3% after the second dose. Persistent antibodies were found in 71.9% of the group that had not received annual vaccinations and in 43.8% of the group that had received annual vaccinations. The latter group tended to have lower HI titers (P = 0.09). With increasing age, HI titers decreased significantly, by 2.4% per year. A single dose of the 2009 vaccine was immunogenic in almost 80% of the study population, whereas an additional dose resulted in significantly increased titers only in persons over 50. Finally, a reduced HI antibody response against the 2009 vaccine was found in adults who had previously received seasonal influenza virus vaccination. More studies on the effect of yearly seasonal influenza virus vaccination on the immune response are warranted. Copyright

Evaluation of sensitivity, specificity and cross-reactivity in Bartonella henselae serology (Article)

2010-06-01T00:00:00Z

Corrigendum to "Strengthening the diagnostic capacity to detect Bio Safety Level 3 organisms in unusual respiratory viral outbreaks" [J. Clin. Virol. 45 (2009) 185-190] (DOI:10.1016/j.jcv.2009.05.024) (Article)

2010-02-01T00:00:00Z

No etiological role for bartonella henselae infection in henoch schönlein purpura (Article)

2009-12-01T00:00:00Z

Strengthening the diagnostic capacity to detect Bio Safety Level 3 organisms in unusual respiratory viral outbreaks (Article)

2009-07-01T00:00:00Z

Background: Experience with a highly pathogenic avian influenza outbreak in the Netherlands (2003) illustrated that the diagnostic demand for respiratory viruses at different biosafety levels (including BSL3), can increase unexpectedly and dramatically. Objectives: We describe the measures taken since, aimed at strengthening national laboratory surge capacity and improving preparedness for dealing with diagnostic demand during outbreaks of (emerging) respiratory virus infections, including pandemic influenza virus. Study design: Academic and peripheral medical-microbiological laboratories collaborated to determine minimal laboratory requirements for the identification of viruses in the early stages of a pandemic or a large outbreak of avian influenza virus. Next, an enhanced collaborative national network of outbreak assistance laboratories (OAL) was set up. An inventory was made of the maximum diagnostic throughput that this network can deliver in a period of intensified demand. For an estimate of the potential magnitude of this surge demand, historical counts were calculated from hospital- and physician-based registries of patients presenting with respiratory symptoms. Results: Number of respiratory physician-visits ranged from 140,000 to 615,000 per month and hospitalizations ranged from 3000 to 11,500 per month. The established OAL-network provides rapid diagnostic response with agreed quality requirements and a maximum throughput capacity of 1275 samples/day (38,000 per month), assuming other routine diagnostic work needs to be maintained. Conclusions: Thus surge demand for diagnostics for hospitalized cases (if not distinguishable from other respiratory illness) could be handled by the OAL network. Assessing etiology of community acquired acute respiratory infection however, may rapidly exceed the capacity of the network. Therefore algorithms are needed for triaging for laboratory diagnostics; currently this is not addressed in pandemic preparedness plans.

Detection of respiratory viruses and Legionella spp. by real-time polymerase chain reaction in patients with community acquired pneumonia (Article)

2009-01-05T00:00:00Z

We conducted a study on throat swabs obtained from a group of hospitalized patients with community acquired pneumonia (CAP). Throat swab specimens from 242 adults admitted to hospital with CAP were tested. In total, 1 or more aetiological agents were identified by real-time PCR in 55 (23%) patients. The most frequently detected pathogens were coronavirus (17%), parainfluenza virus (6%) and influenza virus (4%). Overall, viral pathogens were identified by conventional techniques in 7 (2%) patients, and real-time PCR in 50 (21%) patients (p<0.0001). The diagnostic yield increased from 137 cases (57% of patients using conventional microbiological assays) to 158 cases (65% of patients using real-time PCR assays and conventional microbiological assays; p = 0.06). A significantly higher percentage of mortality was present in patients with a mixed bacterial and viral infection. L. pneumophila PCR was positive in only 3 out of 11 cases (27%) of Legionnaires' disease (LD). This study demonstrates that real-time PCR can increase the number of microbiological detections of respiratory pathogens, mainly as a result of detection of respiratory viruses.