Impact of a quadrivalent meningococcal ACWY glycoconjugate or a serogroup B meningococcal vaccine on meningococcal carriage: an observer-blind, phase 3 randomised clinical trial

Background: Meningococcal conjugate vaccines protect individuals directly, but also confer herd protection by interrupting carriage transmission. This Phase III observer-blind, randomised, controlled study evaluated the effects of meningococcal quadrivalent (ACWY) glycoconjugate (MenACWY-CRM) or serogroup B (4CMenB) vaccination on meningococcal carriage rates in young adults. Methods: University students (aged 18–24 years) from ten sites in England were randomised to receive two vaccinations one month apart: two doses of Japanese Encephalitis vaccine (controls), two doses of 4CMenB (4CMenB), or one dose of MenACWY-CRM then placebo (MenACWY-CRM). Meningococci were isolated from oropharyngeal swabs collected before vaccination and at five scheduled intervals over one year. Primary analysis was cross-sectional carriage one month after the vaccine course; secondary analyses included comparison of carriage at any time point after primary analysis until study termination. Findings: 2954 subjects were randomised (control, n=987; 4CMenB, n=988; MenACWY-CRM, n=979); approximately one-third of each group was positive for meningococcal carriage at study entry. By one month, there was no significant difference in carriage between controls and 4CMenB (Odds Ratios (OR) [95% CI]; 1·2 [0·8−1·7]) or MenACWY-CRM (OR [95% CI], 0·9 [0·6–1·3]) groups. From three months after dose two, 4CMenB vaccination resulted in significantly lower carriage of any meningococcal strain (calculated efficacy 18·2% [95% CI: 3·4–30·8]) and capsular groups BCWY (calculated efficacy 26·6% [95% CI: 10·5–39·9]) compared to control vaccination. Significantly lower carriage rates were also observed in the MenACWY-CRM group compared with controls: calculated efficacies 39·0% [95%CI: 17·3-55·0] and 36.2% [95%CI: 15·6-51·7] for serogroups Y and CWY, respectively. Interpretation: MenACWY-CRM and 4CMenB vaccines reduced meningococcal carriage rates over 12 months post-vaccination and, therefore, may affect transmission where widely implemented

Effect of a quadrivalent meningococcal ACWY glycoconjugate or a serogroup B meningococcal vaccine on meningococcal carriage: an observer-blind, phase 3 randomised clinical trial

Background: Meningococcal conjugate vaccines protect individuals directly, but also confer herd protection by interrupting carriage transmission. This Phase III observer-blind, randomised, controlled study evaluated the effects of meningococcal quadrivalent (ACWY) glycoconjugate (MenACWY-CRM) or serogroup B (4CMenB) vaccination on meningococcal carriage rates in young adults.Methods: University students (aged 18–24 years) from ten sites in England were randomised to receive two vaccinations one month apart: two doses of Japanese Encephalitis vaccine (controls), two doses of 4CMenB (4CMenB), or one dose of MenACWY-CRM then placebo (MenACWY-CRM). Meningococci were isolated from oropharyngeal swabs collected before vaccination and at five scheduled intervals over one year. Primary analysis was cross-sectional carriage one month after the vaccine course; secondary analyses included comparison of carriage at any time point after primary analysis until study termination.Findings: 2954 subjects were randomised (control, n=987; 4CMenB, n=988; MenACWY-CRM, n=979); approximately one-third of each group was positive for meningococcal carriage at study entry. By one month, there was no significant difference in carriage between controls and 4CMenB (Odds Ratios (OR) [95% CI]; 1·2 [0·8−1·7]) or MenACWY-CRM (OR [95% CI], 0·9 [0·6–1·3]) groups. From three months after dose two, 4CMenB vaccination resulted in significantly lower carriage of any meningococcal strain (calculated efficacy 18·2% [95% CI: 3·4–30·8]) and capsular groups BCWY (calculated efficacy 26·6% [95% CI: 10·5–39·9]) compared to control vaccination. Significantly lower carriage rates were also observed in the MenACWY-CRM group compared with controls: calculated efficacies 39·0% [95%CI: 17·3-55·0] and 36.2% [95%CI: 15·6-51·7] for serogroups Y and CWY, respectively.Interpretation: MenACWY-CRM and 4CMenB vaccines reduced meningococcal carriage rates over 12 months post-vaccination and, therefore, may affect transmission where widely implemented

Optical fluorescence studies on sol-gel derived Pr doped silica glasses with added boron

Silica glasses containing Pr with or without boron as a co-dopant were prepared by the sol-gel method at 1100 degrees C. The influence of boron on the Pr doped glasses was studied by UV-visible-NIR, FTIR and fluorescence spectroscopies. The fluorescence intensity of the glasses increased significantly in the presence of boron. This was explained to be due to prevention of the cross relaxation process of these glasses

Study of rehydration process of alumina containing cerium doped silica gels by ultraviolet, visible and FTIR spectroscopy

Alumina containing Ce doped silica xerogel and glasses were prepared by sol-gel processing at 500-1000 degrees C under oxygen atmosphere. The partially densified gels were kept at 80% relative humidity for ageing and spectroscopic properties of the rehydrated partially densified gels were mainly studied by absorption and FTIR spectroscopy. With ageing time the generation of absorption bands of Ce3+ ions suggested the change of local symmetry of the Ce ions. Finally, fourfold splitting was observed for Ce3+ after 60 days indicating eight co-ordinated water complexes like dodecaheral complexes having symmetry group D-2d

Relative reactivities of precursors in the synthesis of forsterite, Mg2SiO4

Three precursors of equivalent oxide composition 2MgO. SiO2, viz. (i) a colloidal gel (partially crystalline) prepared from magnesium nitrate hexahydrate and a colloidal silica sol, (ii) a colloidal gel (partially crystalline) prepared from magnesium chloride n-hydrate and the same colloidal silica sol and (iii) a mechanical mixture of quartz and MgO were used for examining their relative reactivities in the formation of forsterite, Mg2SiO4. The samples were heat treated at temperatures in the range 1000°-1400°C with soaking periods of less than 1 hr to 110 hours. X-ray analyses showed the nitrate-derived gel to be the most reactive, followed by the chloride-derived gel; the crystalline oxide mixture showed sluggish reaction

Effects of PB2+-doping on alkoxide-derived silica sols and gels

Five sols prepared from tetraethyl orthosilicate (TEOS) with 0 to 2 equivalent mol% PbO displayed sharp and progressive changes in the viscosity of the sols, and an increase in viscosity with time and gelling time. Activation energies of gelation (calculated from gelling times at 10, 24, 30, 40 and 50-degrees-C) showed similar sharp changes. The acceleration of gelling time with Pb2+ was found to be much more pronounced than with divalent cations Mg2+, Ca2+ and Zn2+. UV absorption edges of the gels showed significant changes with increase in dopant content, as did the corresponding optical gaps. The acceleration of gelation was considered to be caused by the linkage of Pb2+ with small polymeric clusters via = SiO- terminal groups, and the consequent aggregation of the clusters