Detection of influenza A(H3N2) viruses with polymerase acidic subunit substitutions after and prior to baloxavir marboxil treatment during the 2022-2023 influenza season in Japan.

Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n = 234), with a minor circulation of A(H1N1)pdm09 (n = 10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23 K/G, or I38 M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6-100 %), a polymorphism and a mixture of PA/E23 K/G, and I38 M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 h and a median symptom duration of 93.7 h, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza.

Duration of fever in children infected with influenza A(H1N1)pdm09, A(H3N2) or B virus and treated with baloxavir marboxil, oseltamivir, laninamivir, or zanamivir in Japan during the 2012-2013 and 2019-2020 influenza seasons.

We compared the duration of fever in children infected with A(H1N1)pdm09, A(H3N2), or influenza B viruses following treatment with baloxavir marboxil (baloxavir) or neuraminidase inhibitors (NAIs) (oseltamivir, zanamivir, or laninamivir). This observational study was conducted at 10 outpatient clinics across 9 prefectures in Japan during the 2012-2013 and 2019-2020 influenza seasons. Patients with influenza rapid antigen test positive were treated with one of four anti-influenza drugs. The type/subtype of influenza viruses were identified from MDCK or MDCK SIAT1 cell-grown samples using two-step real-time PCR. Daily self-reported body temperature after treatment were used to evaluate the duration of fever by treatment group and various underlying factors. Among 1742 patients <19 years old analyzed, 452 (26.0%) were A(H1N1)pdm09, 827 (48.0%) A(H3N2), and 463 (26.0%) influenza B virus infections. Among fours treatment groups, baloxavir showed a shorter median duration of fever compared to oseltamivir in univariate analysis for A(H1N1)pdm09 virus infections (baloxavir, 22.0 h versus oseltamivir, 26.7 h, P < 0.05; laninamivir, 25.5 h, and zanamivir, 25.0 h). However, this difference was not significant in multivariable analyses. For A(H3N2) virus infections, there were no statistically significant differences observed (20.3, 21.0, 22.0, and 19.0 h) uni- and multivariable analyses. For influenza B, baloxavir shortened the fever duration by approximately 15 h than NAIs (20.3, 35.0, 34.3, and 34.1 h), as supported by uni- and multivariable analyses. Baloxavir seems to have comparable clinical effectiveness with NAIs on influenza A but can be more effective for treating pediatric influenza B virus infections than NAIs.

Factors associated with viral RNA shedding and evaluation of potential viral infectivity at returning to school in influenza outpatients after treatment with baloxavir marboxil and neuraminidase inhibitors during 2013/2014-2019/2020 seasons in Japan: an observational study.

BACKGROUND: This study assessed the differences in daily virus reduction and the residual infectivity after the recommended home stay period in Japan in patients infected with influenza and treated with baloxavir (BA), laninamivir (LA), oseltamivir (OS), and zanamivir (ZA). METHODS: We conducted an observational study on children and adults at 13 outpatient clinics in 11 prefectures in Japan during seven influenza seasons from 2013/2014 to 2019/2020. Virus samples were collected twice from influenza rapid test-positive patients at the first and second visit 4-5 days after the start of treatment. The viral RNA shedding was quantified using quantitative RT-PCR. Neuraminidase (NA) and polymerase acidic (PA) variant viruses that reduce susceptibility to NA inhibitors and BA, respectively, were screened using RT-PCR and genetic sequencing. Daily estimated viral reduction was evaluated using univariate and multivariate analyses for the factors such as age, treatment, vaccination status, or the emergence of PA or NA variants. The potential infectivity of the viral RNA shedding at the second visit samples was determined using the Receiver Operator Curve based on the positivity of virus isolation. RESULTS: Among 518 patients, 465 (80.0%) and 116 (20.0%) were infected with influenza A (189 with BA, 58 with LA, 181 with OS, 37 with ZA) and influenza B (39 with BA, 10 with LA, 52 with OS, 15 with ZA). The emergence of 21 PA variants in influenza A was detected after BA treatment, but NA variants were not detected after NAIs treatment. Multiple linear regression analysis showed that the daily viral RNA shedding reduction in patients was slower in the two NAIs (OS and LA) than in BA, influenza B infection, aged 0-5 years, or the emergence of PA variants. The residual viral RNA shedding potentially infectious was detected in approximately 10-30% of the patients aged 6-18 years after five days of onset. CONCLUSIONS: Viral clearance differed by age, type of influenza, choice of treatment, and susceptibility to BA. Additionally, the recommended homestay period in Japan seemed insufficient, but reduced viral spread to some extent since most school-age patients became non-infectious after 5 days of onset.

Duration of fever and symptoms in influenza-infected children treated with baloxavir marboxil during the 2019-2020 season in Japan and detection of influenza virus with the PA E23K substitution.

Data on the clinical effectiveness of the novel anti-influenza drug baloxavir marboxil (baloxavir) in children remain limited. We conducted an observational study to compare the duration of fever and symptoms between baloxavir- and oseltamivir-treated children infected with influenza A and B. In total, 159 outpatients with influenza A(H1N1)pdm09 or B/Victoria-lineage infections, aged <19 years, during the 2019-2020 influenza season in Japan were enrolled and assessed the duration of fever and symptoms using the Kaplan-Meier method and a multivariate Cox proportional hazard regression model. Polymerase acidic (PA) variants were examined before and after baloxavir treatment. In the multivariable analysis, the duration of fever and symptoms was unaltered between the A(H1N1)pdm09 (n = 116) and B/Victoria-lineage (n = 43) groups. Conversely, the fever duration was marginally longer in the oseltamivir-treated group (n = 59) than in the baloxavir group (n = 100) (hazard ratio (HR) = 0.67, p = 0.05); however, the duration of symptoms was unaltered between the two groups (HR = 0.74, p = 0.11). No patient presented PA reduced susceptibility marker(s) before baloxavir treatment in the analyzed groups. The PA/E23K variant was detected in one case (1.5%, 1/66) of A(H1N1)pdm09 after baloxavir treatment. One case (2.0%, 1/50) of A(H1N1)pdm09 with an N295S substitution in neuraminidase was detected following oseltamivir treatment. These results suggested that the duration of fever was likely to be shorter with baloxavir than with oseltamivir, but the difference between influenza A (H1N1)pdm09 and B/Victoria-lineage was unclear. It is important to continue evaluating the clinical effectiveness of baloxavir and monitoring its drug susceptibility to the influenza virus.

Very low-density lipoprotein in the cord blood of preterm neonates.

Human fetuses have markedly low levels of serum lipids and a unique lipoprotein profile with respect to quality, with low-density lipoprotein (LDL)-like particle as the dominant cholesterol carrier. However, little is known about triglyceride (TG) distribution. In addition, lipid metabolism is important in lung development, with indications that TG from very low-density lipoprotein (VLDL) is essential for surfactant synthesis. We investigated TG distribution in preterm neonate cord blood and the relationship of VLDL-TG levels with respiratory distress syndrome (RDS). The study included 103 appropriate-for-gestational-age neonates (61 males). We performed serum lipoprotein analyses in cord blood by high-performance liquid chromatography with gel permeation columns. Term neonates had low cord blood TG concentrations distributed equally to the LDL and VLDL fractions. However, preterm neonates had even lower TG concentrations, with VLDL as the dominant carrier. The LDL-TG and high-density lipoprotein-TG concentrations in cord blood increased gradually with gestational age, but cord blood VLDL-TG concentrations increased dramatically from 32 to 34 weeks of gestational age. Neonates with RDS exhibited no RDS-specific lipoprotein profile; however, most were born before the timing of the dramatic VLDL-TG increase. Our results suggest that 34 weeks of gestation is a critical period for TG metabolism, indicating the need for evaluation of the lipid nutritional state in preterm neonates.

A role of end-tidal CO(2) monitoring for assessment of tracheal intubations in very low birth weight infants during neonatal resuscitation at birth.

AIM: To investigate whether end-tidal CO(2) monitoring is useful for more rapid recognition of tracheal vs. esophageal intubation as compared to standard clinical evaluation in very low birth weight infants during neonatal resuscitation at birth. PATIENTS AND METHODS: Forty infants were prospectively identified. Tracheal tube placement was evaluated either using an end-tidal CO(2) monitor by an investigator not involved in the resuscitation, or by evaluation of clinical parameters by a resuscitation team unaware of the end-tidal CO(2) data. The time taken to detect accurate placement of the tube using capnometory vs. clinical determination of tracheal or esophageal tube placement was compared. RESULTS: A total of 54 intubations was analyzed from 40 neonates. End-tidal CO(2) monitoring correctly identified all 40 tracheal and all 11 esophageal intubations with 100% accuracy. On the other hand, clinical evaluation demonstrated discrepancies in three cases. The mean time in seconds for capnographic determination was significantly faster than clinical determination for both tracheal (7.5+/-1.3 vs. 17.0+/-3.4, P<0.01) and esophageal intubation (6.5+/-0.7 vs. 19.9+/-1.8, P<0.01). CONCLUSION: Exhaled CO(2) detection is a sensitive and accurate technique to confirm tracheal tube placement in very low birth weight infants during neonatal resuscitation.

Effect of hemoglobin on transfusion and neonatal adaptation in extremely low-birthweight infants.

BACKGROUND: The aim of the present paper was to investigate the effect of initial hemoglobin level on red blood cell transfusion and neonatal adaptation in extremely low-birthweight (ELBW) infants. METHODS: Subjects consisted of 54 ELBW infants admitted to level III neonatal intensive care unit between 1995 and 2000, and divided into two groups based on hemoglobin level at birth. High hemoglobin was defined as hemoglobin > or =15.0 g/dL. RESULTS: There were no significant differences in gestational age and birthweight between the high hemoglobin group (n = 28) and low hemoglobin group (n = 26). The high hemoglobin group had decreased probability of requiring red blood cell transfusion (P < 0.05) and number of red blood cell transfusions (P < 0.05). Mortality rate in the low hemoglobin group was significantly higher compared with the high hemoglobin group (P = 0.03). In the high hemoglobin group, blood pressures during the first 24 h were significantly higher (P < 0.05) and the risk of intraventricular hemorrhage was significantly lower (P = 0.04) compared with the low hemoglobin group. The predictive variables, initial hemoglobin level (odds ratio 1.93 [decrease by 1 g/dL]) and intraventricular hemorrhage > or =III (odds ratio 21.76 [positive]) were found to be most predictive for death on logistic regression. CONCLUSION: High hemoglobin level at birth is associated with a significantly reduced requirement for red blood cell transfusion and might contribute to stabilization of blood pressure, and thus reduce mortality and the risk of severe intraventricular hemorrhage.

Kinetics of serum S100B in newborns with intracranial lesions.

BACKGROUND: The purpose of the present study was to evaluate the usefulness of serum S100B as a clinical marker of intracranial lesions in newborns. METHODS: The study involved 22 normal and 40 diseased newborns. Serum S100B level was measured on days 1 and 6 in normal newborns. Diseased newborns were classified into four groups: birth asphyxia with hypoxic-ischemic encephalopathy (HIE); birth asphyxia without HIE; intracranial hemorrhage (mainly subarachnoid); and brain malformation. In each group the serum S100B level was measured on days 1, 2 and 6. Development was also assessed to investigate the relation between serum S100B level and prognosis at 18 months after birth. RESULTS: In normal newborns, serum S100B level was significantly higher in those with liquor to meconium stain than in those without. In diseased newborns, serum S100B level on day 1 was significantly higher in the HIE group than in all other groups (P < 0.05). There was no significant difference in serum S100B level between control and intracranial hemorrhage, or brain malformation. In newborns with birth asphyxia, serum S100B level was significantly higher in severe birth asphyxia than in mild or moderate birth asphyxia; two newborns with serum S100B level > or =10 microg/L on days 1 and 2 developed cerebral palsy, others with no increase of S100B were all developing normally. CONCLUSIONS: Serum S100B level is a useful marker of acute perinatal brain damage, and is particularly valuable for fetal distress. In newborns with birth asphyxia, serum S100B levels serve as a biochemical marker of HIE.

Heterogeneity of high-density lipoprotein in cord blood and its postnatal change.

BACKGROUND: Several subclasses of HDL are demonstrated to have different roles in atherosclerosis based on adult studies, but the significance of HDL heterogeneity in the fetus and neonate has not been clarified. It has been described that the cholesterol supply from apoE-rich HDL is essential for central nerve system neuron growth. METHODS: Sixty-five healthy, term, appropriate for gestational age neonates (38 males and 27 females) were included in the study. Serum lipoprotein analyses were performed by HPLC with gel permeation columns, which classified HDL into 5 subgroups (i.e., very large, large, medium, small, and very small) on the basis of particle size. Apolipoprotein A-I, B, and E were also determined by turbidimetric immunoassay. RESULTS: Cord blood has higher very large and very small HDL-cholesterol levels. Cord blood apolipoprotein E was not uniformly distributed in the HDL subclasses, with a strong association with very large HDL-cholesterol levels (males, r=0.548, p<0.001; females, r=0.631, p<0.01). However, the association disappeared by 1 month of age in males; in females, the association remained during the neonatal period. CONCLUSIONS: These results suggest that HDL may play the role of a dominant cholesterol carrier in the human fetus, and very large HDL-cholesterol have some contribution to the neurodevelopment in the fetus and neonates because of the close relationship with apolipoprotein E levels.

Impact of serum adiponectin concentration on birth size and early postnatal growth.

In term neonates, the adiponectin concentration is higher than it is in adults. To determine the relationship between adiponectin and early neonatal growth in a cohort study. Fifty-two neonates at term were studied. Serum adiponectin concentrations, body sizes, and skinfold thicknesses were measured at birth and at 1 mo of age. At birth, cord blood adiponectin concentration correlated positively with birth weight (r = 0.484, p = 0.0003), birth length (r = 0.524, p < 0.0001), and sum of the four skinfold thickness measurements (r = 0.378, p = 0.0057). In a stepwise regression, birth length was the only determinant of cord blood adiponectin concentration. However, at 1 mo of age, serum adiponectin concentration correlated with no anthropometric parameter at all. Between birth and 1 mo of age, the individual change in adiponectin concentration correlated negatively with birth weight. Thus, serum adiponectin concentrations in cord blood have a strong relationship to birth length rather than to body fatness, and this relationship is not demonstrated in 1-mo-old infants. These results imply that hormonal, substrate, or other mechanisms that regulate the relationship between body composition and growth in fetal life are different from those governing these relationships in early postnatal life.

Prediction of transfusions in extremely low-birthweight infants in the erythropoietin era.

BACKGROUND: The purpose of the present paper was to detect the clinical factors most predictive of red blood cell (RBC) transfusion in extremely low-birthweight (ELBW) infants in the recombinant human erythropoietin era. METHODS: Between 1995 and 2000, 66 ELBW infants were admitted to a level III neonatal intensive care unit. Fifty-four of 66 infants were eligible for enrollment in the present study. Infants were treated with erythropoietin 200 IU/kg per dose s.c. twice a week with 4-6 mg/kg per day iron supplement. RESULTS: The mean gestational age and birthweight were 26.5 +/- 2.1 weeks and 776 +/- 134 g, respectively. Ten of 54 ELBW infants (18.5%) died during the first 21 days. Eight of 10 dead infants (80.0%) and 27 of 44 surviving infants (61.4%) received one or more RBC transfusions. The overall requirement for RBC transfusions in the surviving infants was 3.0 +/- 3.2 per infant/hospital course (range: 0-9) . There were significant differences in gestational weeks, birthweight, initial hemoglobin value, 5 min Apgar score, phlebotomy loss, phlebotomy loss/birthweight, duration of mechanical ventilation, duration of oxygen supplement, and incidence of both intraventricular hemorrhage and chronic lung disease between the transfused and non-transfused group. The predictive variables, initial hemoglobin level (odds ratio [OR] 2.61; 1 g/dL), birthweight (OR 3.00; 100 g), and gestational week (OR 1.89; 1 week), were found to be most predictive for transfusion on logistic regression analysis. CONCLUSION: ELBW infants are still the population at greatest risk for repeated blood transfusions after introduction of erythropoietin treatment. If labor develops, it is often impossible to extend the pregnancy period, therefore efforts should be made to increase hemoglobin level at birth.

Autologous cord blood transfusion in an infant with a huge sacrococcygeal teratoma.

We describe a case of cord blood harvest for autologous transfusion in a neonate weighing 3,992 g with a giant sacrococcygeal teratoma. The umbilical vein was pierced with an 18-gauge needle, and placental blood was withdrawn into two 50-ml syringes filled with 4 ml of citrate-phosphate-dextrose solution. Resection of the sacrococcygeal teratoma was performed on day one. During the operation the infant lost 46 ml of whole blood, more than 15% of the estimated total blood volume, and thus underwent autologous transfusion with 27.8 ml of packed red cells obtained from autologous cord blood. Consequently, she could avoid homologous blood transfusion during the hospital stay. This case highlights the safety of this procedure, with no evidence of consumption coagulopathy, hemolysis or bacterial infection.