Usefulness of multiplex PCR methods and respiratory viruses' distribution in children below 15 years old according to age, seasons and clinical units in France: A 3 years retrospective study.

BACKGROUND:To date, only influenza and RSV testing are recommended for respiratory viruses' detection in paediatric units. In this study, we described, according to seasons, ages and clinical units, the results obtained in children (<15 years old) by multiplex-PCR (mPCR) tests allowing a quick and wide range detection of all respiratory viruses. These results were also compared with RSV specific detection. METHODS:All nasopharyngeal mPCR and RSV tests requested by clinicians in our French teaching hospitals group between 2011 and 2014 were retrospectively included. All repeated samples for the same children in the same month were discarded. RESULTS:Of the 381 mPCR tests (344 children) performed, 51.4% were positive. Positivity and viral co-infection rates were higher in the 6-36 months old strata (81% and 25%, p<0.0001 and p = 0.04, respectively). Viral distribution showed strong variations across ages. During specific influenza epidemic periods, only 1/39 (2.5%) mPCR tests were positive for influenza and 19/39 (48.7%) for other viruses. During specific RSV epidemic periods, only 8/46 (17.4%) mPCR tests were positive for RSV and 14/46 (30.4%) for other viruses. 477/1529 (31.2%) of RSV immunochromatography-tests were positive. Among the negatives immunochromatography-test also explored by mPCR, 28/62 (31%) were positive for other respiratory viruses. CONCLUSION:This study provides a wide description of respiratory viruses' distribution among children in hospital settings using mPCR over 3 years. It emphasizes the number of undiagnosed respiratory viruses according to the current diagnosis practice in France and gives a better picture of respiratory viruses identified in hospital settings by mPCR all over the year in France

Characteristics of patients and multiplex PCR results across units and age strata.

<p>Characteristics of patients and multiplex PCR results across units and age strata.</p

Positivity rates obtained by multiplex PCR and RSV specific immunchromatographic tests according to age and medical units.

<p>Positivity rates obtained by multiplex PCR and RSV specific immunchromatographic tests according to age and medical units.</p

Proportion of each respiratory viruses detected by mPCR in viral mono or co-infection.

<p>Proportion of each respiratory viruses detected by mPCR in viral mono or co-infection.</p

Distribution of all respiratory viruses isolated across age strata.

<p>The total number of isolated viruses is indicated at the top of each bar.</p

Temporal distribution of respiratory viruses identified by multiplex PCR.

<p>(A) in adults (<15 years) and (B) in children (>15 years).</p

Neonatal outcomes for women at risk of preterm delivery given half dose versus full dose of antenatal betamethasone: a randomised, multicentre, double-blind, placebo-controlled, non-inferiority trial

International audienceBackgroundAntenatal betamethasone is recommended before preterm delivery to accelerate fetal lung maturation. However, reports of growth and neurodevelopmental dose-related side-effects suggest that the current dose (12 mg plus 12 mg, 24 h apart) might be too high. We therefore investigated whether a half dose would be non-inferior to the current full dose for preventing respiratory distress syndrome.MethodsWe designed a randomised, multicentre, double-blind, placebo-controlled, non-inferiority trial in 37 level 3 referral perinatal centres in France. Eligible participants were pregnant women aged 18 years or older with a singleton fetus at risk of preterm delivery and already treated with the first injection of antenatal betamethasone (11·4 mg) before 32 weeks’ gestation. We used a computer-generated code producing permuted blocks of varying sizes to randomly assign (1:1) women to receive either a placebo (half-dose group) or a second 11·4 mg betamethasone injection (full-dose group) 24 h later. Randomisation was stratified by gestational age (before or after 28 weeks). Participants, clinicians, and study staff were masked to the treatment allocation. The primary outcome was the need for exogenous intratracheal surfactant within 48 h after birth. Non-inferiority would be shown if the higher limit of the 95% CI for the between-group difference between the half-dose and full-dose groups in the primary endpoint was less than 4 percentage points (corresponding to a maximum relative risk of 1·20). Four interim analyses monitoring the primary and the secondary safety outcomes were done during the study period, using a sequential data analysis method that provided futility and non-inferiority stopping rules and checked for type I and II errors. Interim analyses were done in the intention-to-treat population. This trial was registered with ClinicalTrials.gov, NCT02897076.FindingsBetween Jan 2, 2017, and Oct 9, 2019, 3244 women were randomly assigned to the half-dose (n=1620 [49·9%]) or the full-dose group (n=1624 [50·1%]); 48 women withdrew consent, 30 fetuses were stillborn, 16 neonates were lost to follow-up, and 9 neonates died before evaluation, so that 3141 neonates remained for analysis. In the intention-to-treat analysis, the primary outcome occurred in 313 (20·0%) of 1567 neonates in the half-dose group and 276 (17·5%) of 1574 neonates in the full-dose group (risk difference 2·4%, 95% CI –0·3 to 5·2); thus non-inferiority was not shown. The per-protocol analysis also did not show non-inferiority (risk difference 2·2%, 95% CI –0·6 to 5·1). No between-group differences appeared in the rates of neonatal death, grade 3–4 intraventricular haemorrhage, stage ≥2 necrotising enterocolitis, severe retinopathy of prematurity, or bronchopulmonary dysplasia.InterpretationBecause non-inferiority of the half-dose compared with the full-dose regimen was not shown, our results do not support practice changes towards antenatal betamethasone dose reduction