A new European perspective of influenza pandemic planning with a particular focus on the role of mammalian cell culture vaccines

Sixteen EU scientists and doctors were interviewed about pandemic planning using psychometric methods applied to a scientific problem for the first time. Criticism was aimed at countries which have no plan whatsoever, the majority of nations. Many such countries have not invested in scientific infrastructure and public health. Amongst the 15 or so published pandemic plans a lack of detail was identified. Of particular need was investment into avian virus vaccine stocks (H1-15), prepared licenses of vaccine and pre purchase and agreed distribution, investment into stocks of antivirals, antibiotics and masks. Most but not all members of the group predicted a global outbreak within 5 years, most probably starting in SE Asia. However it was recognised that a pandemic could start anywhere in the world which had juxtaposition of young people, chickens, ducks and pigs. Mammalian cell culture production using wild type virus with the production factory at category III levels of security was exemplified. Antivirals would be essential to ameliorate the first wave of infection although significant quantities of cell grown vaccine could be produced if, as in 1918, 1957 and 1968 there is a long period between the first virus isolation and person to person spread. The wider scientific community is more energised than previously for very serious preparations to be in place way before the outbreak begins as this is a major public health problem, completely dwarfing concerns about bioterrorism.     

Method for using complete and incomplete trios to identify genes related to a quantitative trait

A number of tests for linkage and association with qualitative traits have been developed, with the most well-known being the transmission/disequilibrium test (TDT). For quantitative traits, varying extensions of the TDT have been suggested. The quantitative trait approach we propose is based on extending the log-linear model for case-parent trio data (Weinberg et al. [1998] Am. J. Hum. Genet. 62:969-978). Like the log-linear approach for qualitative traits, our proposed polytomous logistic approach for quantitative traits allows for population admixture by conditioning on parental genotypes. Compared to other methods, simulations demonstrate good power and robustness of the proposed test under various scenarios of the genotype effect, distribution of the quantitative trait, and population stratification. In addition, missing parental genotype data can be accommodated through an expectation-maximization (EM) algorithm approach. The EM approach allows recovery of most of the lost power due to incomplete trios.     

Vaccine protection in the elderly: are Austrian seniors adequately protected by vaccinations?

OBJECTIVE: The aim of the study was to evaluate, if elderly persons are sufficiently protected against infectious diseases by vaccination. PROBANDS AND METHODS: 300 elderly (> 60 years) and 300 young (< 35 years) persons from five Austrian cities were recruited according to the criteria of a field study. Antibody concentrations against tetanus, diphtheria, tickborne encephalitis and influenza were assessed by ELISA or by haemagglutination inhibition test. Disease and vaccination histories were recorded. RESULTS: The results of the study demonstrate that protection against infectious diseases was frequently insufficient in the elderly. This was partly due to the fact that old persons were not vaccinated according to recommended strategies. However, low antibody concentration and a short duration of protective humoral immunity were also observed in many elderly persons in spite of regular vaccination. This was not only the case in frail, but also in healthy elderlies. CONCLUSION: The data demonstrate that vaccination has a relatively weak and short-lasting effect in old age. The results of the study should stimulate discussions about strategies how vaccinations can be made more effective in old age. Improved campaigns, shortened vaccination intervals as well as the design of novel vaccines tailored to fulfill the specific demands of the aging immune system are imaginable.     

Mechanism of venous valve closure and role of the valve in circulation: a new concept

PURPOSE: The purpose of this study was to investigate the blood flow changes and venous wall movements that occur in the perivalvular area during venous flow, to learn how these physiologic events influence the movements of the valve cusps, and to learn how the movements of the valve cusps influence the venous flow. MATERIALS AND METHODS: Twenty healthy volunteers (10 male, 10 female, age 18 to 52) were subjects of this study. Each volunteer was examined in semi-recumbent and standing positions at rest and during active foot movements. Ultrasound examinations were performed in the B-flow mode supplemented by B-mode and pulsed-wave Doppler scanning. RESULTS: Four phases of the valve cycle are described. During the opening phase (0.27 +/- 0.05 s), the cusps move from the closed position toward the sinus wall. After reaching a certain point, the valves cease opening and enter the equilibrium phase. During this phase (0.65 +/- 0.08 s), the leading edges remain suspended in the flowing stream and undergo self-excited oscillations with an amplitude of 0.01 to 0.16 cm. During the closing phase (0.41 +/- 0.07 sec), the leaflets move synchronously toward the center of the vein. The subsequent closed phase has a duration of 0.45 +/- 0.05 seconds when the cusps remain closed. During the equilibrium phase, flow separation occurs at the leading edge of the cusp with reattachment at the wall of sinus. At this point, flow splits into two streams at each valve cusp. Part of the flow is directed into the sinus pocket behind the valve cusp, forming a vortex along the valve cusp before re-emerging in the main stream in the vein. When the valve is maximally open, the two cusps create a narrowing of the lumen about 35% smaller than the vein distal to the valve. In this narrowed area flow accelerates, forming a proximally directed jet. CONCLUSIONS: The valve cusps undergo the four phases constituting the valve cycle. The local hemodynamic events, such as flow separation and reattachment, and vortical flow in the sinus play important roles in the valve operation. In addition to prevention of retrograde flow, the valve acts as a venous flow modulator. The vortical stream behind the valve cusps participates in the operation of the valve, and prevents stasis inside the valve pocket. The central jet possibly facilitates outflow.     

Prospective randomized study of endovenous radiofrequency obliteration (closure procedure) versus ligation and stripping in a selected patient population (EVOLVeS Study)

PURPOSE: This study was designed as a prospective multicenter randomized comparison of procedure-related complications, patient recuperation, and quality-of-life outcomes between patients undergoing vein stripping with high ligation and patients undergoing great saphenous vein (GSV) obliteration with temperature-controlled radiofrequency ablation without adjunctive high ligation (Closure procedure). METHODS: Eighty-five patients (86 limbs) from five sites (France, 2; Austria, 1; United States, 2) were randomly allocated to undergo radiofrequency obliteration (RFO) or stripping and high ligation (S&L). Final analysis included data for 44 limbs in the RFO group and 36 limbs in the S&L group. Follow-up examinations were performed at 72 hours, 1 week, 3 weeks, and 4 months. All patients completed the CIVIQ2 quality-of-life (QOL) questionnaire and underwent clinical and ultrasound examinations at each follow-up visit. RESULTS: Immediate success on the day of treatment was reported for 95% (42 of 44) of limbs in the RFO group and 100% (36 of 36) of limbs in the S&L group. In seven RFO limbs (16.3%) a scan obtained 72 hours after the procedure showed flow in the proximal GSV. Five of these segments had reflux in the open segment. At 1 week two of these closed, and an additional segment closed at 3 weeks. In no cases did flow reappear after complete occlusion of the GSV. Time to return to normal activities was significantly less in the RFO group (mean, 1.15 days; 95% confidence interval [CI], 0.05-2.34) compared with the S&L group (mean, 3.89 days; CI, 2.67-5.12; P =.02). In the RFO group, 80.5% of patients returned to routine activities of daily living within 1 day, compared with 46.9% of patients in the S&L group (P <.01). Patients in the RFO group were able to return to work in 4.7 days (CI, 1.16-8.17), compared with 12.4 days (CI, 8.66-16.23) for the S&L group (P <.05). Analysis of the QOL surveys showed statistically significant differences in favor of the RFO group for global score and pain score during follow-up. The magnitude of the difference, however, progressively decreased between 1 week and 4 months. CONCLUSIONS: In the absence of significant complications, such as deep vein thrombosis and pulmonary embolism, severe neuritic sequelae, and skin burns, there are significant early advantages to endovascular obliteration of the GSV compared with conventional vein stripping.     

A novel mammalian cell (Vero) derived influenza virus vaccine: development, characterization and industrial scale production

Influenza virus for vaccine production are presently produced in embryonated chicken eggs. This conventional standard methodology is extremely cumbersome; it requires a huge amount of eggs and an extensive purification to reduce the amount of contaminating egg proteins and to minimize the risk of allergies against egg albumin. The shortage of eggs in a pandemic situation, the selection of egg-adapted variants and the presence of adventitious viruses has emphasized the necessity for production of influenza vaccines on a well characterized stable cell line. Our established Vero cell technology has been successfully adapted to large scale production of a variety of influenza virus strains. The production in 1200 litre fermenter cultures under serum-free conditions gave antigen yields comparable to the conventional embryonated egg technology. The development of a rapid and efficient purification scheme resulted in a safe high purity vaccine which was at least as immunogenic as conventional egg-derived vaccines in a mouse model. This vaccine has been shown to be safe and highly immunogenic in chimpanzees and to be capable of protecting ferrets against challenge with live virus. Clinical trials have now been initiated in the UK and Austria.     

Controlled trial of continuous inflating pressure for hyaline membrane disease

A controlled trial of elective intervention with continuous inflating pressure (CIP) was performed in infants with severe hyaline membrane disease who weighed more than 1000 g at birth. Infants entered the trial if their arterial oxygen tension (PaO2) fell below 60 mmHg while breathing a fractional inspired oxygen concentration (F1O2) greater than 0-95. 11 out of 12 infants in the CIP-treated group and 10 out of 12 in the control group survived. 7 treated and 6 control infants required mechanical ventilation. When CIP was started the Pao2 of the treated infants increased, and they breathed high concentrations of oxygen for a significantly shorter period than the control infants. During the 31-month duration of the trial 107 other infants with severe hyaline membrane disease were admitted who did not meet the criteria for entry to the trial. 37 survived after breathing high concentrations of oxygen (F1O2 greater than 0-60) spontaneously without any ventilatory assistance, and the remaining 70 infants were already being ventilated on their arrival in the unit, usually because they had required mechanical ventilation during transfer from other hospitals. The neonatal survival rate for those infants born in this hospital during the study period was 88% (50 out of 57 infants) and for those referred from other hospitals it was 69% (51 out of 74 infants). The maximum further increase in overall survival rate that might have been achieved in our population of infants if CIP had been initiated very early in the course of the illness was 5%--i.e. from 77% (101/131) to 82% (107/131).     

Comparison of single,homologous prime-boost and heterologous prime-boost immunization strategies against H5N1 influenza virus in a mouse challenge model

Preparation for an H5N1 influenza pandemic in humans may involve priming the population with a vaccine produced from an existing, available H5N1 strain. We have used a mouse challenge model to compare the immunogenicity and efficacy of inactivated, Vero cell-derived, whole virus H5N1 vaccines in single immunization and homologous or heterologous prime-boost regimes. A single immunization was sufficient to protect against a lethal challenge with strains from matched and unmatched H5N1 clades. Homologous and heterologous prime-boost regimes induced cross-neutralizing antibodies and cross-protection against representative viruses of H5N1 clade 1, clade 2.1, clade 2.2 and clade 2.3. Moreover, the results indicate that heterologous prime-boost immunization regimes might broaden the specificity of the anti-H5N1 antibody response.