Relationship between haemagglutination-inhibiting antibody titres and clinical protection against influenza: development and application of a bayesian random-effects model

<p>Abstract</p> <p>Background</p> <p>Antibodies directed against haemagglutinin, measured by the haemagglutination inhibition (HI) assay are essential to protective immunity against influenza infection. An HI titre of 1:40 is generally accepted to correspond to a 50% reduction in the risk of contracting influenza in a susceptible population, but limited attempts have been made to further quantify the association between HI titre and protective efficacy.</p> <p>Methods</p> <p>We present a model, using a meta-analytical approach, that estimates the level of clinical protection against influenza at any HI titre level. Source data were derived from a systematic literature review that identified 15 studies, representing a total of 5899 adult subjects and 1304 influenza cases with interval-censored information on HI titre. The parameters of the relationship between HI titre and clinical protection were estimated using Bayesian inference with a consideration of random effects and censorship in the available information.</p> <p>Results</p> <p>A significant and positive relationship between HI titre and clinical protection against influenza was observed in all tested models. This relationship was found to be similar irrespective of the type of viral strain (A or B) and the vaccination status of the individuals.</p> <p>Conclusion</p> <p>Although limitations in the data used should not be overlooked, the relationship derived in this analysis provides a means to predict the efficacy of inactivated influenza vaccines when only immunogenicity data are available. This relationship can also be useful for comparing the efficacy of different influenza vaccines based on their immunological profile.</p

Can a surgeon predict the longevity of a total hip replacement?

Introduction: The purpose of this study was to examine the ability of a surgeon to predict survival of a total hip replacement (THR) based on the patient’s diagnosis, demographics, postoperative activity level and the surgical technique. Methods: 4 experienced hip surgeons were asked to predict the longevity of 131 Charnley THRs, performed by the senior author (GH) 22–35 years ago, by providing them with pre- and postoperative radiographs, and data concerning patient’s diagnosis, demographics, postoperative activity level and the surgical technique. This process was repeated 3 months later. Results: There was only a slight agreement between the majority of the predictions and actual outcome. The inter-observer agreement was also slight and intra-observer agreement ranged from slight to moderate. Conclusion: We confirmed that surgeons are unable to determine the life expectancy of the implants of a THR, based on the aforementioned data, because there are other non-identified factors that affect the survivorship of a THR. For this reason, regular follow-up remains the safest way to evaluate patients’ clinical picture and the evolution of radiographic changes, if there are any, in order to accurately advise patients and decide on the appropriate time for revision. © The Author(s) 2019

High complication rate in reconstruction of Paprosky type IIIa acetabular defects using an oblong implant with modular side plates and a hook

We report the results of 62 hips in 62 patients (17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent revision of the acetabular component of a total hip replacement due to aseptic loosening between May 2003 and November 2007. All hips had a Paprosky type IIIa acetabular defect. Acetabular revision was undertaken using a Procotyl E cementless oblong implant with modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients lost to follow-up and one died due to unrelated illness, the complication rate was 38.7%. Complications included aseptic loosening (19 hips), deep infection (3 hips), broken hook and side plate (one hip) and a femoral nerve palsy (one hip). Further revision of the acetabular component was required in 18 hips (29.0%) and a further four hips (6.4%) are currently loose and awaiting revision. We observed unacceptably high rates of complication and failure in our group of patients and cannot recommend this implant or technique