Seasonal trivalent influenza vaccination during pregnancy and the incidence of stillbirth: population-based retrospective cohort study

Concern for the safety to the fetus is a commonly cited reason for vaccine refusal during pregnancy. Results from this investigation support the safety of seasonal influenza vaccination during pregnancy and suggest seasonal influenza vaccination may be protective against stillbirth

Does influenza vaccination improve pregnancy outcome? Methodological issues and research needs

AbstractEvidence that influenza vaccination during pregnancy is safe and effective at preventing influenza disease in women and their children through the first months of life is increasing. Several reports of reduced risk of adverse outcomes associated with influenza vaccination have generated interest in its potential for improving pregnancy outcome. Gavi, the Vaccine Alliance, estimates maternal influenza immunization programs in low-income countries would have a relatively modest impact on mortality compared to other new or under-utilized vaccines, however the impact would be substantially greater if reported vaccine effects on improved pregnancy outcomes were accurate. Here, we examine the available evidence and methodological issues bearing on the relationship between influenza vaccination and pregnancy outcome, particularly preterm birth and fetal growth restriction, and summarize research needs. Evidence for absence of harm associated with vaccination at a point in time is not symmetric with evidence of benefit, given the scenario in which vaccination reduces risk of influenza disease and, in turn, risk of adverse pregnancy outcome. The empirical evidence for vaccination preventing influenza in pregnant women is strong, but the evidence that influenza itself causes adverse pregnancy outcomes is inconsistent and limited in quality. Studies of vaccination and pregnancy outcome have produced mixed evidence of potential benefit but are limited in terms of influenza disease assessment and control of confounding, and their analytic methods often fail to fully address the longitudinal nature of pregnancy and influenza prevalence. We recommend making full use of results of randomized trials, re-analysis of existing observational studies to account for confounding and time-related factors, and quantitative assessment of the potential benefits of vaccination in improving pregnancy outcome, all of which should be informed by the collective engagement of experts in influenza, vaccines, and perinatal health

Aspects of noncommutative Lorentzian geometry for globally hyperbolic spacetimes

Connes' functional formula of the Riemannian distance is generalized to the Lorentzian case using the so-called Lorentzian distance, the d'Alembert operator and the causal functions of a globally hyperbolic spacetime. As a step of the presented machinery, a proof of the almost-everywhere smoothness of the Lorentzian distance considered as a function of one of the two arguments is given. Afterwards, using a $C^*$-algebra approach, the spacetime causal structure and the Lorentzian distance are generalized into noncommutative structures giving rise to a Lorentzian version of part of Connes' noncommutative geometry. The generalized noncommutative spacetime consists of a direct set of Hilbert spaces and a related class of $C^*$-algebras of operators. In each algebra a convex cone made of self-adjoint elements is selected which generalizes the class of causal functions. The generalized events, called {\em loci}, are realized as the elements of the inductive limit of the spaces of the algebraic states on the $C^*$-algebras. A partial-ordering relation between pairs of loci generalizes the causal order relation in spacetime. A generalized Lorentz distance of loci is defined by means of a class of densely-defined operators which play the r\^ole of a Lorentzian metric. Specializing back the formalism to the usual globally hyperbolic spacetime, it is found that compactly-supported probability measures give rise to a non-pointwise extension of the concept of events.Comment: 43 pages, structure of the paper changed and presentation strongly improved, references added, minor typos corrected, title changed, accepted for publication in Reviews in Mathematical Physic

Cosmological perturbations on local systems

We study the effect of cosmological expansion on orbits--galactic, planetary, or atomic--subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity--in particular, we find the gravitational field of a mass distribution in an expanding universe by applying perturbation theory to the Robertson-Walker metric. Cosmological expansion induces an ($\ddot a/a) \vec r$ force where $a(t)$ is the cosmological scale factor. In a locally Newtonian framework, we show that the $(\ddot a/a) \vec r$ term represents the effect of a continuous distribution of cosmological material in Hubble flow, and that the total force on an object, due to the cosmological material plus the matter perturbation, can be represented as the negative gradient of a gravitational potential whose source is the material actually present. We also consider the effect on local dynamics of the cosmological constant. We calculate the perihelion precession of elliptical orbits due to the cosmological constant induced force, and work out a generalized virial relation applicable to gravitationally bound clusters.Comment: 10 page

Localizations at infinity and essential spectrum of quantum Hamiltonians: I. General theory

We isolate a large class of self-adjoint operators H whose essential spectrum is determined by their behavior at large x and we give a canonical representation of their essential spectrum in terms of spectra of limits at infinity of translations of H. The configuration space is an arbitrary abelian locally compact not compact group.Comment: 63 pages. This is the published version with several correction