Neutralizing Antibody Levels as a Correlate of Protection Against SARS-CoV-2 Infection: A Modeling Analysis.

Although anti-severe acute respiratory syndrome-coronavirus 2 antibody kinetics have been described in large populations of vaccinated individuals, we still poorly understand how they evolve during a natural infection and how this impacts viral clearance. For that purpose, we analyzed the kinetics of both viral load and neutralizing antibody levels in a prospective cohort of individuals during acute infection with alpha variant. Using a mathematical model, we show that the progressive increase in neutralizing antibodies leads to a shortening of the half-life of both infected cells and infectious viral particles. We estimated that the neutralizing activity reached 90% of its maximal level within 11 days after symptom onset and could reduce the half-life of both infected cells and circulating virus by a 6-fold factor, thus playing a key role to achieve rapid viral clearance. Using this model, we conducted a simulation study to predict in a more general context the protection conferred by pre-existing neutralization titers, due to either vaccination or prior infection. We predicted that a neutralizing activity, as measured by 50% effective dose > 103 , could reduce by 46% the risk of having viral load detectable by standard polymerase chain reaction assays and by 98% the risk of having viral load above the threshold of infectiousness. Our model shows that neutralizing activity could be used to define correlates of protection against infection and transmission.

Circulating bile acids concentration is predictive of coronary artery disease in human.

Synthetized by the liver and metabolized by the gut microbiota, BA are involved in metabolic liver diseases that are associated with cardiovascular disorders. Animal models of atheroma documented a powerful anti-atherosclerotic effect of bile acids (BA). This prospective study examined whether variations in circulating BA are predictive of coronary artery disease (CAD) in human. Consecutive patients undergoing coronary angiography were enrolled. Circulating and fecal BA were measured by high pressure liquid chromatography and tandem mass spectrometry. Of 406 screened patients, 80 were prospectively included and divided in two groups with (n = 45) and without (n = 35) CAD. The mean serum concentration of total BA was twice lower in patients with, versus without CAD (P = 0.005). Adjusted for gender and age, this decrease was an independent predictor of CAD. In a subgroup of 17 patients, statin therapy doubled the serum BA concentration. Decreased serum concentrations of BA were predictors of CAD in humans. A subgroup analysis showed a possible correction by statins. With respect to the anti-atherosclerotic effect of BA in animal models, and their role in human lipid metabolism, this study describe a new metabolic disturbance associated to CAD in human.

Educational and health outcomes associated with bronchopulmonary dysplasia in 15-year-olds born preterm.

INTRODUCTION: To evaluate the consequences of bronchopulmonary dysplasia (BPD) on academic outcomes and healthcare use in adolescents born very preterm. METHODS: This cohort study included 15-year-old adolescents born very preterm (< 32 weeks) between 2011 and 2013, with and without BPD, and controls born full term. Data regarding academic performance, current medical follow-up, and family characteristics were collected. Multivariate logistic regression was used to quantify relationships between academic outcomes and BPD. RESULTS: From the 1341 children included in the initial cohort, 985 adolescents were eligible and 351 included (55 preterms with a history of BPD, 249 without, and 47 controls). Among adolescents born very preterm, a history of BPD was associated with a higher risk to attend a school for children with special needs (p < 0.05) and to have repeated a grade (p = 0.01). It was also associated with an increased number of medical and paramedical consultations. A history of BPD was not associated with the parents' employment status, family structure, or the presence of younger siblings. CONCLUSION: This study highlights that a history of BPD is associated with poorer academic outcomes and high healthcare use in adolescence.

Association between asthma and lung function in adolescents born very preterm: results of the EPIPAGE cohort study.

Prematurity and bronchopulmonary dysplasia (BPD) affect long-term lung function. We studied the respiratory outcome of adolescents born very preterm and controls from the Etude EPIdémiologique sur les Petits Ages Gestationnels cohort and analysed their current lung function in relation to asthma symptoms (categorised in three age groups) from birth. In models including BPD, asthma at each age and confounding factors in the preterm group, BPD and preschool wheeze were the only independent variables associated with FEV1 Preschool wheeze is an independent factor associated with FEV1 impairment in adolescents born very preterm. These results highlight the need for optimal management of early respiratory symptoms in preterm-born infants. TRIAL REGISTRATION NUMBER: Results, NCT01424553.