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Background 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. Methods 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. Results 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. Conclusion 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.

The COVID-19 pandemic in France induced the development of a national, high spatiotemporal resolution confirmed infection cases database. We aimed to estimate the predictive ability of census-based indicators on the infection risk to assess their potential usefulness in future pandemic response. We collected and aggregated all counts of biologically confirmed cases of SARS-CoV-2 infection in the Auvergne-Rhône-Alpes region in France at small-area statistical units between May 2020 and February 2021 (second wave). Ten census-based ecological covariates were evaluated as predictors of case incidence using a Poisson regression with conditional autoregressive (CAR) spatial effects. Benefits of CAR effects and covariates on model predictive ability was assessed comparing posterior predictive distribution of case incidence with the observed value for each statistical unit. Among 7,917,997 inhabitants, 438,992 infection cases over 5410 neighbourhoods were analysed. Spatial correlation was high for the periods before and after the epidemic peak, and illustrated with cartography. The addition of covariates to the null model led to an increase in satisfying prediction of + 5% from 14%, with a maximum of 21% across all periods. The ecological covariates assessed were insufficient to provide a satisfying prediction of infection risk without explicitly accounting for the spatial organization of the epidemic.

Worldwide, COVID-19 outbreaks in nursing homes have often been sudden and massive. The study investigated the role SARS-CoV-2 virus spread in nearby population plays in introducing the disease in nursing homes. This was carried out through modelling the occurrences of first cases in each of 943 nursing homes of Auvergne-Rhône-Alpes French Region over the first epidemic wave (March-July, 2020). The cumulative probabilities of COVID-19 outbreak in the nursing homes and those of hospitalization for the disease in the population were modelled in each of the twelve Départements of the Region over period March-July 2020. This allowed estimating the duration of the active outbreak period, the dates and heights of the peaks of outbreak probabilities in nursing homes, and the dates and heights of the peaks of hospitalization probabilities in the population. Spearman coefficient estimated the correlation between the two peak series. The cumulative proportion of nursing homes with COVID-19 outbreaks was 52% (490/943; range: 22-70% acc. Département). The active outbreak period in the nursing homes lasted 11 to 21 days (acc. Département) and ended before lockdown end. Spearman correlation between outbreak probability peaks in nursing homes and hospitalization probability peaks in the population (surrogate of the incidence peaks) was estimated at 0.71 (95% CI: [0.66; 0.78]). The modelling highlighted a strong correlation between the outbreak in nursing homes and the external pressure of the disease. It indicated that avoiding disease outbreaks in nursing homes requires a tight control of virus spread in the surrounding populations.

Introduction The antiretroviral therapy (ART) programme supported by Médecins Sans Frontières in the rural Malawian district of Chiradzulu was one of the first in sub‐Saharan Africa to scale up ART delivery in 2002. After more than a decade of continuous involvement, we conducted a population survey to evaluate the cascade of care, including population viral load, in the district. Methods A cross‐sectional household‐based survey was conducted between February and May 2013. Using a multistage cluster sampling method, we recruited all individuals aged 15 to 59 years living in 4125 randomly selected households. Each consenting individual was interviewed and tested for HIV at home. All participants who tested positive had their CD4 count and viral load measured. The LAg‐Avidity assay was used to distinguish recent from long‐term infections. Viral suppression was defined as a viral load below 1000 copies/mL. Results Of 8271 individuals eligible for the study, 7269 agreed to participate and were tested for HIV (94.1% inclusion for women and 80.3% for men). Overall HIV prevalence and incidence were 17.0% (95% CI 16.1 to 17.9) and 0.39 new cases per 100 person‐years (95% CI 0.0 to 0.77), respectively. Coverage at the other steps along the HIV care cascade was as follows: 76.7% (95% CI 74.4 to 79.1) had been previously diagnosed, 71.2% (95% CI 68.6 to 73.6) were under care and 65.8% (95% CI 62.8 to 68.2) were receiving ART. Finally, the proportion of participants who were HIV positive with a viral load ≤1000 copies/mL reached 61.8% (95% CI 59.0 to 64.5). Conclusions This study demonstrates that a high level of population viral suppression and low incidence can be achieved in high HIV prevalence and resource‐limited settings.

IntroductionProstate multiparametric MRI (mpMRI) has shown good sensitivity in detecting cancers with an International Society of Urological Pathology (ISUP) grade of ≥2. However, it lacks specificity, and its inter-reader reproducibility remains moderate. Biomarkers, such as the Prostate Health Index (PHI), may help select patients for prostate biopsy. Computer-aided diagnosis/detection (CAD) systems may also improve mpMRI interpretation. Different prototypes of CAD systems are currently developed under the Recherche Hospitalo-Universitaire en Santé / Personalized Focused Ultrasound Surgery of Localized Prostate Cancer (RHU PERFUSE) research programme, tackling challenging issues such as robustness across imaging protocols and magnetic resonance (MR) vendors, and ability to characterise cancer aggressiveness. The study primary objective is to evaluate the non-inferiority of the area under the receiver operating characteristic curve of the final CAD system as compared with the Prostate Imaging-Reporting and Data System V.2.1 (PI-RADS V.2.1) in predicting the presence of ISUP ≥2 prostate cancer in patients undergoing prostate biopsy.MethodsThis prospective, multicentre, non-inferiority trial will include 420 men with suspected prostate cancer, a prostate-specific antigen level of ≤30 ng/mL and a clinical stage ≤T2 c. Included men will undergo prostate mpMRI that will be interpreted using the PI-RADS V.2.1 score. Then, they will undergo systematic and targeted biopsy. PHI will be assessed before biopsy. At the end of patient inclusion, MR images will be assessed by the final version of the CAD system developed under the RHU PERFUSE programme. Key secondary outcomes include the prediction of ISUP grade ≥2 prostate cancer during a 3-year follow-up, and the number of biopsy procedures saved and ISUP grade ≥2 cancers missed by several diagnostic pathways combining PHI and MRI findings.Ethics and disseminationEthical approval was obtained from the Comité de Protection des Personnes Nord Ouest III (ID-RCB: 2020-A02785-34). After publication of the results, access to MR images will be possible for testing other CAD systems.Trial registration numberNCT04732156.

The worldwide global increase in serum 25-hydroxyvitamin D (25(OH)D) measurements has led some countries to restrict reimbursement for certain clinical situations only. Another approach could consist in providing physicians with screening tools in order to better target blood test prescription. The objective of the SCOPYD study was to identify the best combination of predictors of serum VitD concentration among adults aged 18–70 years. Potential risk factors for VitD deficiency were collected using a comprehensive self-administered questionnaire. A multivariable linear regression was used to build a predictive model of serum 25(OH)D concentration. Among 2488 participants, 1080 (43.4%) had VitD deficiency (<50 nmol/L) and 195 (7.8%) had severe deficiency (<25 nmol/L). The final model included sunlight exposure in the preceding week and during the last holidays, month of blood sampling, age, sex, body mass index, skin phototype, employment, smoking, sport practice, latitude, and VitD supplementation in preceding year. The area under the curve was 0.82 (95% CI (0.78; 0.85)) for severe deficiency. The model predicted severe deficiency with a sensitivity of 77.9% (95% CI (69.1; 85.7)) and a specificity of 68.3% (95% CI (64.8; 71.9)). We identified a set of predictors of severe VitD deficiency that are easy to collect in routine that may help to better target patients for serum 25(OH)D concentration determination.

Background Toxoplasma gondii , the agent of toxoplasmosis, has a complex life cycle. In humans, the parasite may be acquired either through ingestion of contaminated meat or through oocysts present in the environment. The importance of each source of contamination varies locally according to the environment characteristics and to differences concerning human eating habits and the presence of cats; thus, the risk factors may be determined through fine-scale studies. Here, we searched for factors associated with seropositivity in the population of two adjacent villages in Lorraine region, France. Methods All voluntary inhabitants filled out a questionnaire and gave a blood sample. The seroprevalence was estimated globally and according to the inhabitants' ages using a cubic spline regression. A mixed logistic regression model was used to quantify the effect of individual and household factors on the probability of seropositivity. Results Based on serological results from 273 persons, we estimated seroprevalence to be 47% (95% confidence interval: 41 to 53%). That seroprevalence increased with age: the slope was the steepest up to the age of 40 years (OR = 2.48 per 10-year increment, 95% credibility interval: [1.29 to 5.09]), but that increase was not significant afterwards. The probability of seropositivity tended to be higher in men than in women (OR = 2.01, 95% credibility interval: [0.92 to 4.72]) and in subjects eating raw vegetables at least once a week than in the others (OR = 8.4, 95% credibility interval: [0.93 to 72.1]). These effects were close to statistical significance. The multivariable analysis highlighted a significant seroprevalence heterogeneity among households. That seroprevalence varied between 6 and 91% (5 th and 95 th percentile of the household seropositivity distribution). Conclusion The major finding is the household effect, with a strong heterogeneity of seroprevalence among households. This effect may be explained by common exposures of household members to local risk factors. Future work will quantify the link between the presence of oocysts in the soil and the seroprevalence of exposed households using a spatial analysis.

Mathematical models have played important roles in the understanding of epidemics and in the study of the impacts of various behavioral or medical measures. However, modeling accurately the future spread of an epidemic requires context-specific parameters that are difficult to estimate because of lack of data. Our objective is to propose a methodology to estimate context-specific parameters using Demographic and Health Survey (DHS)-like data that can be used in mathematical modeling of short-term HIV spreading. The model splits the population according to sex, age, HIV status, and antiretroviral treatment status. To estimate context-specific parameters, we used individuals' histories included in DHS-like data and a statistical analysis that used decomposition of the Poisson likelihood. To predict the course of the HIV epidemic, sex- and age-specific differential equations were used. This approach was applied to recent data from Kenya. The approach allowed the estimation of several key epidemiological parameters. Women had a higher infection rate than men and the highest infection rate in the youngest age groups (15-24 and 25-34 years) whereas men had the highest infection rate in age group 25-34 years. The immunosuppression rates were similar between age groups. The treatment rate was the highest in age group 35-59 years in both sexes. The results showed that, within the 15-24 year age group, increasing male circumcision coverage and antiretroviral therapy coverage at CD4 ≤ 350/mm3 over the current 70% could have short-term impacts. The study succeeded in estimating the model parameters using DHS-like data rather than literature data. The analysis provides a framework for using the same data for estimation and prediction, which can improve the validity of context-specific predictions and help designing HIV prevention campaigns.

Background and Aims. European recommendations on cardiovascular prevention suggest that carotid atherosclerosis assessment by duplex ultrasonography could help in some cases to better assess CV risk. We investigated whether the presence of carotid atherosclerosis determined by duplex ultrasonography is associated with cardiovascular events in patients with type 2 diabetes and could therefore help to reclassify cardiovascular risk. Methods. Among 624 consecutive patients with type 2 diabetes and carotid atherosclerosis assessment by duplex ultrasonography between January and December 2012, 583 (93%) were included and followed up prospectively. The primary endpoint was the occurrence of cardiovascular events. The rate of new cardiovascular events was compared between patients with (n=104) and those without (n=479) prior cardiovascular events. Results. A total of new 104 cardiovascular events occurred in 72 patients (12.5%) during a mean±SD follow-up period of 5.1±1.6 years. At baseline, for 202 patients (34.6%), carotid evaluation was normal; 381 (65.4%) had a carotid atherosclerosis lesion. The presence of carotid atherosclerosis at baseline was not significantly associated with an increased risk of new cardiovascular events in both groups. The rate of new cardiovascular events was more than twice as high in patients with prior cardiovascular event than those without. Conclusion. Systematic carotid atherosclerosis assessment by duplex ultrasonography in patients with type 2 diabetes and a contemporary cardiovascular prevention treatment does not offer additional information as to the risk of cardiovascular events. This trial is registered with ClinicalTrials.gov (ID: NCT02929355).

Abstract Aims After transcatheter aortic valve replacement (TAVR), cardiovascular and non-cardiovascular comorbidities may offset the survival benefit from the procedure. We aimed to describe the relationships between that benefit and patient comorbidities. Methods and results The study pooled two European cohorts of patients with severe aortic stenosis (AS-pooled): one with patients who underwent (cohort of AS patients treated by TAVR, N = 233) and another with patients who did not undergo TAVR (cohort of AS patients treated medically; N = 291). The investigators collected the following: calcification prognostic impact (CAPRI) and Charlson scores for cardiovascular and non-cardiovascular comorbidities, activities of daily living (ADL)/instrumental activities of daily living (IADL) scores for frailty as well as routine Society of Thoracic Surgeons (STS) score and Logistic Euroscore. Unlike ADL/IADL scores, CAPRI and Charlson scores were found to be independent predictors of 1-year all-cause death in the AS-pooled cohort, with and without adjustment for STS score or Logistic Euroscore; they were thus retained to define a three-level prognostic scale (good, intermediate, and poor). The survival benefit from TAVR—vs. no TAVR—was stratified according to these three prognosis categories. The beneficial effect of TAVR on 1-year all-cause death was significant in patients with good and intermediate prognosis, hazard ratio (95% confidence interval): 0.36 (0.18; 0.72) and 0.32 (0.15; 0.67). That effect was reduced and not statistically significant in patient with poor prognosis [0.65 (0.22; 1.88)]. Conclusion The study showed that, beyond a given comorbidity burden (as assessed by CAPRI and Charlson scores), the probability of death within a year was high and poorly reduced by TAVR. This indicates the futility of TAVR in patients in the poor prognosis category. Graphical Abstract Graphical Abstract Relationship between prognosis category and the transcatheter aortic valve replacement (TAVR) effect. Prognosis categories were defined using the tertiles of calcification prognostic impact and Charlson scores. The estimates of 1-year all-cause death probabilities in each cohort (cohort of AS patients treated medically and cohort of AS patients treated by TAVR) were obtained using a multivariable Cox regression model. The mortality curves were obtained using an interpolated polynomial of degree 2 based on those estimates. The hatched area indicates the difference in the probability of 1-year death between the two cohorts and illustrates mainly the TAVR effect. While both TAVR and the prognosis category contributed to 1-year all-cause death, the contribution of TAVR was not uniform across the range of prognoses; the poorer was the prognosis category, the lower was the benefit from TAVR.