Validation of a commercially available SARS-CoV-2 serological immunoassay.

OBJECTIVES: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA immunoassay for COVID-19. METHODS: In this unmatched (1:2) case-control validation study, we used sera of 181 laboratory-confirmed SARS-CoV-2 cases and 326 controls collected before SARS-CoV-2 emergence. Diagnostic accuracy of the immunoassay was assessed against a whole spike protein-based recombinant immunofluorescence assay (rIFA) by receiver operating characteristic (ROC) analyses. Discrepant cases between ELISA and rIFA were further tested by pseudo-neutralization assay. RESULTS: COVID-19 patients were more likely to be male and older than controls, and 50.3% were hospitalized. ROC curve analyses indicated that IgG and IgA had high diagnostic accuracies with AUCs of 0.990 (95% Confidence Interval [95%CI]: 0.983-0.996) and 0.978 (95%CI: 0.967-0.989), respectively. IgG assays outperformed IgA assays (p=0.01). Taking an assessed 15% inter-assay imprecision into account, an optimized IgG ratio cut-off > 2.5 displayed a 100% specificity (95%CI: 99-100) and a 100% positive predictive value (95%CI: 96-100). A 0.8 cut-off displayed a 94% sensitivity (95%CI: 88-97) and a 97% negative predictive value (95%CI: 95-99). Substituting the upper threshold for the manufacturer's, improved assay performance, leaving 8.9% of IgG ratios indeterminate between 0.8-2.5. CONCLUSIONS: The Euroimmun assay displays a nearly optimal diagnostic accuracy using IgG against SARS-CoV-2 in patient samples, with no obvious gains from IgA serology. The optimized cut-offs are fit for rule-in and rule-out purposes, allowing determination of whether individuals in our study population have been exposed to SARS-CoV-2 or not. IgG serology should however not be considered as a surrogate of protection at this stage.

Objectifying psychomental stress in the workplace--an example.

BACKGROUND: Psychomental stress is a major source of illness and reduced productivity. Data objectifying physiological stress responses are scarce. We studied salivary cortisol levels in a highly stressful environment, the pediatric critical care unit. The aim was to identify targets for organizational changes, to implement these changes and to assess their impact on cortisol levels. DESIGN: Repeated measurements observational cohort study (before and after intervention). SUBJECTS: 84 nurses working in two independent teams (A and B) in a 19 bed pediatric intensive care unit. Between study periods team A experienced a major exchange of experienced staff while the turnover rate in team B remained average. MEASUREMENTS AND INTERVENTIONS: Salivary cortisol samples were collected every 2 h and after stressful events. Nurses in study period I showed elevated cortisol levels at the beginning of the late shift, interpreted as an anticipatory stress reaction. To ease conditions during the early part of the late shift (conflicting tasks, noise and crowding), we postponed the afternoon ward round, limited non-urgent procedures and introduced a change in visiting hours. The early shift, which was not affected by the intervention, served as control. MAIN RESULTS: Both crude and adjusted analysis revealed a decrease of cortisol levels at the beginning of the late shift in team B (p = 0.0009), but not in team A (p = 0.464). The control situation showed no difference between teams and study periods. INTERPRETATION: We demonstrated reduced cortisol secretions in one team following organizational changes, which was probably overridden by the disruption of social coherence in the second team.

Experience and endocrine stress responses in neonatal and pediatric critical care nurses and physicians.

OBJECTIVE: Critical care is a working environment with frequent exposure to stressful events. High levels of psychological stress have been associated with increased prevalence of burnout. Psychological distress acts as a potent trigger of cortisol secretions. We attempted to objectify endocrine stress reactivity. DESIGN: Observational cohort study during two 12-day periods in successive years. SETTING: A tertiary multidisciplinary neonatal and pediatric intensive care unit (33 beds). SUBJECTS: One hundred and twelve nurses and 27 physicians (94% accrual rate). INTERVENTIONS AND MEASUREMENTS: Cortisol determined from salivary samples collected every 2 hrs and after stressful events. Participants recorded the subjective perception of stress with every sample. Endocrine reactions were defined as transient surges in cortisol of >50% and 2.5 nmol/L over the baseline. MAIN RESULTS: During 7,145 working hours, we observed 474 (12.5%) endocrine reactions from 3,781 samples. The mean cortisol increase amounted to 10.6 nmol/L (219%). The mean occurrence rate of endocrine reactions per subject and sample was 0.159 (range, 0-0.43). Although the mean raw cortisol levels were lower in experienced team members (>3 yrs of intensive care vs. <3 yrs, 4.1 vs. 4.95 nmol/L, p < .001), professional experience failed to attenuate the frequency and magnitude of endocrine reactions, except for the subgroup of nurses and physicians with >8 yrs of intensive care experience. A high proportion (71.3%) of endocrine reactions occurred without conscious perception of stress. Unawareness of stress was higher in intensive care nurses (75.1%) than in intermediate care nurses (51.8%, p < .01). CONCLUSIONS: Stress-related cortisol surges occur frequently in neonatal and pediatric critical care staff. Cortisol increases are independent of subjective stress perception. Professional experience does not abate the endocrine stress reactivity.

Impact of infertility treatments on the health of newborns.

OBJECTIVE: To measure the use of infertility treatments in the general population and their association with neonatal health. DESIGN: Cross-sectional, population-based study. SETTING: Canton of Vaud, Switzerland; Etude du Developpement des Nouveau-nés (EDEN), a prospective study of chronic childhood conditions. PATIENT(S): Six thousand four hundred seventy-seven live newborns (6,379 pregnancies) delivered of residents of Vaud in the 19 maternity hospitals between 1993 and 1994. MAIN OUTCOME MEASURE(S): Neonatal morbidity, multiplicity, low birth weight, prematurity, intrauterine growth retardation, transfer to intensive care, and length of hospital stay. RESULT(S): Infertility treatments were reported for 2.1% of pregnancies (129 women, 148 newborns) and were associated significantly with adverse outcomes. Population-attributable risks varied from 3%-20%. The outcomes of twins did not differ regardless of whether their mother was treated for infertility. Among singletons, only low birth weight was significantly more frequent when infertility treatments were used. Unadjusted odds ratios for neonatal morbidity were significant only for multiple births (2.56; 95% confidence interval 1.21-5.42). This association was not influenced by maternal characteristics and it disappeared after controlling for sex, gestational age, and birth weight. CONCLUSIONS(S): An independent effect of infertility treatments on neonatal morbidity cannot be ruled out, but most of their impact appeared to be mediated by multiplicity and prematurity. Reducing the number of medically induced multiple pregnancies is the most effective prevention of neonatal morbidity related to infertility treatments. Follow-up studies are needed.

Enrollment of a population-based cohort of newborns at higher risk of developing a chronic condition: the EDEN study. Etude du Developpement des Nouveau-nés Study.

OBJECTIVE: To describe the methods used at birth to recruit a population-based cohort of newborns of all birthweights at higher risk of having a chronic condition, and to present baseline results. METHODS: Screening of all newborns at hospital discharge for five non-exclusive criteria: (1) low birthweight (LBW), (2) congenital anomalies or genetic disease, (3) specified conditions associated with a high probability of chronicity, (4) referral to a neonatal intensive care unit (NICU), (5) or defined social problems. Calculation of Hobel risk scores for children satisfying > or = 1 criterion. SUBJECTS: All 6477 live births delivered in the 19 maternity hospitals of a geographically defined region (Vaud, Switzerland) to resident mothers in 1993-1994. RESULTS: Twelve per cent (n = 760) of newborns met > or = 1 criterion: 6.3% of all newborns had an LBW (criterion 1), 2.4% had a birth defect, 0.9% met criterion (3), 4.4% stayed in an NICU and 1.6% had serious social problems. Hobel prenatal score was high (> or = 10 points) for 41% of children with > or = 1 criterion, the intrapartum score for 87% and the neonatal score for 68%. CONCLUSIONS: Most newborns identified by the above simple criteria also had elevated perinatal risks. The validity of the criteria will later be tested against the results of the examinations of children with > or = 1 criterion at 18 months and 4 years of age, but the assessment at birth already shows that normal birthweight (NBW) children, in agreement with previous studies, contribute half the children at high risk perinatally.

Risk factors of sensorineural hearing loss in preterm infants.

Among 547 preterm infants of < or = 34 weeks gestation born between 1987 and 1991, 8 children (1.46%) developed severe progressive and bilateral sensorineural hearing loss. Perinatal risk factors of infants with hearing loss were compared with those of two control groups matched for gestation and birth weight and for perinatal complications. Our observations demonstrated an association of hearing loss with a higher incidence of perinatal complications. Ototoxicity appeared closely related to a prolonged administration and higher total dose of ototoxic drugs, particularly aminoglycosides and furosemide. Finally, we strongly recommend to prospectively and regularly perform audiologic assessment in sick preterm children as hearing loss is of delayed onset and in most cases bilateral and severe.

Haemodynamic changes during high frequency oscillation for respiratory distress syndrome.

In a crossover trial left ventricular output (LVO), cerebral blood flow velocity (CBFV), and resistance index (RI) of the anterior cerebral artery were compared using Doppler ultrasonography, in eight preterm infants with respiratory distress syndrome (RDS) during conventional mechanical ventilation and high frequency oscillation. LVO was 14% to 18% lower with high frequency oscillation. There were no significant changes in CBFV. On the first day of life there was a trend towards lower RI on high frequency oscillation; the fall in LVO on high frequency oscillation was not related to lung hyperinflation. Changes in ventilation type (from conventional mechanical ventilation to high frequency oscillation, or vice versa) can induce significant LVO changes in preterm infants with RDS.

Influence of perinatal, developmental and environmental factors on cognitive abilities of preterm children without major impairments at 5 years.

The relative role of perinatal factors (birthweight, gestational age, gender, asphyxia, mechanical ventilation and cerebral lesions), developmental factors (neuromotor development during the first 18 months of life) and environmental factors (socio-economic status and bilingualism) on cognitive abilities was evaluated in a cohort of preterm children who had been prospectively examined for haemorrhage (PVH) and periventricular leucomalacia (PVL) and followed-up to 5 years of age. Standardized neurological examinations and development assessment including tests of cognitive function were carried out. Major impairments could be ascribed to the presence of large PVL changes. Among the 226 children without major impairment, the overall incidence of neuropsychological anomalies (neuromotor, language, visual, auditory and behaviour anomalies) was 46.5% and did not differ within ultrasound groups (normal scans, PVH and small PVL). However, children with small changes of PVL presented more abnormal neuromotor development within the first 18 months of life and had more complex neuropsychological anomalies at 5 years. The multiple regression analysis (General Intellectual Index (GII) predicted = 113.7 - coefficient x social class - 8.5 x bilingualism - 5.5 x dystonia + 1.4 x gestational age + 8 x mechanical ventilation) showed that socioeconomic status was the most important factor affecting the General Intellectual Index (GII). The contribution of sex and cerebral lesions was not significant. As children grew-up, environmental factors seemed to overcome perinatal factors.

Magnesium sulphate as an alternative and safe treatment for severe persistent pulmonary hypertension of the newborn.

Eleven newborns admitted consecutively to the neonatal unit with respiratory failure and severe persistent pulmonary hypertension (PPHN) were included in a clinical trial to assess the efficacy of magnesium sulphate (MgSO4) in the treatment of PPHN. A loading dose of 200 mg/kg MgSO4 was given over 20 minutes, followed by a continuous infusion of 20-150 mg/kg/hour to obtain a magnesium blood concentration between 3.5 and 5.5 mmol/l. Mean (SD) duration of treatment was 75.5 (19.8) hours. No other vasodilatory drug was administered before or during the treatment and patients were not hyperventilated. Mean (SEM) PaO2 values significantly increased from 42.6 (8.8) before treatment to 70.3 (24.1) mm Hg after 24 hours, with no change in pH or PCO2. Oxygen index and alveolar-arterial oxygen gradient (A-aDO2) were significantly lower after 24 hours; respectively, 46.8 (15.2) to 28.0 (9.0) and 624.3 (11.3) to 590 (58) mm Hg. Mean airway pressure could be significantly reduced from 19.5 (3.1) to 13.9 (3.9) cm H2O after 72 hours. Mean ventilatory time support was 131 hours and mean total oxygen dependency 10 days. No systemic hypotension nor any other adverse effect were noted. All infants survived and the neurodevelopmental assessment was normal at 6 and 12 months of age. It is concluded that magnesium sulphate is a non-aggressive and low-cost treatment of short duration which is easy to apply. It may have a role in the various treatment of PPHN.

[Congenital toxoplasmosis: pediatric approach. Consensus report of the Swiss infectious disease pediatricians]. / Toxoplasmose congénitale: prise en charge pédiatrique. Texte de consensus des pédiatres infectiologues suisses.

The first part of this paper reviews: (1) the spectrum of clinical features of congenital toxoplasmosis; (2) the natural course of fetal infection; (3) the influence of antitoxoplasma therapy on the course of the disease; (4) methods for diagnosing the toxoplasma infection and assessing the severity of the disease; (5) currently used antitoxoplasma drugs and different therapeutic regimens. The second part suggests a practical approach to the problem of congenital toxoplasma infection, including diagnostic work-up, drug therapy, and follow-up. This practical approach is modulated according to the clinical syndrome in the infant and diagnostic and therapeutic considerations in the mother.

Water, energy and early postnatal growth in preterm infants.

Non-invasive methods, including stable isotope techniques, indirect calorimetry, nutritional balance and skinfold thickness, have given a new insight into early postnatal growth in neonates. Neonates and premature infants in particular, create an unusual opportunity to study the fluid and metabolic adaptation to extrauterine life because their physical environment can be controlled, fluid and energy balance can be measured and the link between metabolism and the energetics of their postnatal growth can be assessed accurately. Thus the postnatal time course of total body water, heat production, energy cost of growth and composition of weight gain have been quantified in a series of "healthy" low-birth-weight premature infants. These results show that total body water is remarkably stable between postnatal days 3-21. Energy expenditure and heat production rates increase postnatally from mean values of 40 kcal/kg/day during the first week to 60 kcal/kg/day in the third week. An apparent energy balance deficit of 180 kcal/kg can be ascribed to premature delivery. The cost of protein metabolism is the highest energy demanding process related to growth. The fact that nitrogen balance becomes positive within 72 h after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism during early postnatal growth: skinfold thickness, dry body mass and fat decrease, while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches statural growth. The goals of the following review are to summarize data on total body water and energy metabolism in premature infants and to discuss how they correlate with physiological aspects of early postnatal growth.

[Extremely premature infants: what is their future? Lausanne experience 1982-1992]. / Prématurés extrêmes: quel devenir? Expérience lausannoise 1982-1992.

This study describes neonatal mortality and morbidity as well as the neuropsychological outcome of extremely-low-birth-weight infants (less than 1000 grams) born between 1/1/1982 and 12/31/1992. The number of preterm infants admitted to the neonatal unit has increased over the last ten years. If neonatal mortality remains high, the prognosis of these immature children is favourable and depends on close collaboration between obstetricians and neonatologists and on the quality of perinatal care.