Macronutrient content of pasteurised donor human milk: Variability between batches from single-donor pools at an Australian milk bank.

AIM: This study aimed to characterise the between-batch variability of pasteurised donor human milk (PDHM) produced from single-donor pools at Australian Red Cross Lifeblood's milk bank and identify key donor characteristics that predict macronutrient content. METHODS: Macronutrient content from 200 batches of PDHM was measured using a mid-infrared human milk analyser (Miris, Uppsala, Sweden). Linear mixed models were used to study the impact of stage of lactation and gestational age on macronutrient content. Coefficients of determination (R2 ) were calculated to estimate the impact of the individual donor on overall variability. RESULTS: Macronutrient content of PDHM varied considerably, with between-batch variations of 2.8 and 6.4-fold for protein and fat content, respectively. Mean crude protein content was 1.16 g/100 mL, ranging from 0.7 to 1.96 g/100 mL. Mean fat content was 3.85 g/100 mL, ranging from 1.46 to 9.39 g/100 mL. Stage of lactation was identified as a predictor for protein content and gestational age at birth for fat content. Individual donor effect explained 55 and 35% of the variance for fat and protein content, respectively. CONCLUSIONS: This study highlights the variation in macronutrient content in PDHM at an Australian milk bank. Variability could be reduced through the implementation of targeted multiple-donor pooling using the key donor characteristics identified in this study along with the measurement of macronutrient content of individual donors at the time of first donation. However, the clinical benefit of a reduction in between-batch variation, achieved through multiple-donor pooling, would need to be assessed to justify additional efforts associated with PDHM processing changes.

Use of a paediatric advice line for parents of infants recruited to a randomised controlled trial.

BACKGROUND: This study aims to describe the use of a paediatric advice line (PAL) provided to parents whose infants were recruited to a large randomised controlled trial (RCT), including the number and types of medical concerns addressed, seasonal variability and call outcomes. Additionally, sociodemographic characteristics of the parents and children of those parents who used the PAL are compared with those who did not. METHODS: Prospective cohort of 1246 children nested in the Melbourne Infant Study: BCG for Allergy and Infection Reduction (MIS BAIR) RCT. All MIS BAIR participants were offered access to the PAL. Data were collected over the initial 2 years of a 5-year follow-up. Data were analysed using χ2 tests, and ORs were calculated using multiple logistic regression. RESULTS: The PAL was used by 230 (18.5%) participants, who made a total of 586 calls during the 2-year study period. The reasons for calling the PAL were dermatological (24%); gastrointestinal (18%); disturbances in feeding, sleeping and crying (14%); respiratory (7%); and developmental/neurological (6%). Analysis revealed that those who used the PAL were more likely to be first-time parents (OR 1.4, 95% CI 1.1 to 1.9) and mothers who hold a university degree (OR 3.3, 95% CI 1.3 to 8.4). PAL costs were minimal and comprised 15 clinicians with paediatric experience. CONCLUSIONS: A cost-effective PAL service for clinical trial participants was used appropriately by parents for relatively minor concerns and may have a role in trials to promote participant engagement and reduce demand for other health services.

Clinical and Health System Impact of Biofire Filmarray Meningitis/Encephalitis Routine Testing of CSF in a Pediatric Hospital: An Observational Study.

BACKGROUND: Rapid cartridge-based molecular test panels targeting multiple pathogens are increasingly available, improve pathogen detection and reduce turn-around-time but are more expensive than standard testing. Confirmation that these test panels contribute to improved patient or health service outcomes is required. METHODS: In March 2021, our pediatric hospital laboratory implemented the BioFire Filmarray™ meningitis/encephalitis (M/E) panel as an additional routine test for all cerebrospinal fluid (CSF) samples collected from infants <90 days or from any patient in the emergency department. A retrospective chart review was done to ascertain changes in clinical outcomes, antimicrobial prescribing practices, and hospital length of stay, comparing two discrete 6-month periods: preimplementation (March-August 2019) and postimplementation (March-August 2021). RESULTS: Both pre- and postimplementation groups were similar at baseline, except the preimplementation group had a higher proportion of infants with enterovirus and parechovirus meningitis. There was no significant difference between the groups in terms of median length of stay (2.94 vs 3.47 days, p = 0.41), duration of antibiotic treatment (2.0 vs 2.3 days, p = 0.25), need for central venous access (12.9% vs 17%, p = 0.38) or hospital-in-the-home admission (9.4% vs 9%, p = 0.92). A similar proportion of infants received aciclovir (33% vs 31%), however, a reduction in duration was observed (1.36 vs 0.90 days, p = 0.03) in the postimplementation period. CONCLUSIONS: Introduction of the Biofire Filmarray™ M/E panel for routine testing of CSF samples reduced the duration of antiviral prescribing but had only a minor impact on antibiotic prescribing practices or health service outcomes in our pediatric hospital. The introduction of new laboratory testing needs to be supported by a comprehensive stewardship program to see optimal outcomes from new testing platforms.

Understanding Mothers' Experiences of Being Ineligible to Donate Their Milk to a Not-for-Profit Milk Bank.

Background: Donor milk banks have strict donor screening criteria to ensure that donor milk is safe for premature or hospitalized babies. Yet little evidence is available to understand how potential donors, who are often breastfeeding their own infants, experience being ineligible ("deferred") to donate their milk to a milk bank. Materials and Methods: Interviews were conducted with 10 mothers who were permanently or temporarily deferred from donating to a large, not-for-profit milk bank in Australia. Interviews focused on becoming a donor and being deferred, meanings of deferral, impact of deferral on feeding own infant, and improving the deferral process. Results: Thematic analysis of interviews identified nine themes: (1) donation as a solution to wasting milk; (2) eligibility questions were acceptable and understandable; (3) more information early on allows self-deferral; (4) deferral is not always clear; (5) deferral is disappointing but does not prevent future donation; (6) deferral did not prevent feeding own infant; (7) early information enables preparation for donation; (8) slow communication disrupts perfect timing to donate; and (9) alternatives to wasting milk. Conclusions: Milk banks have a duty of care to both milk recipients and donors. While mothers who want to donate milk are disappointed by deferrals, clear communication protects their breastfeeding relationships with their own infants. Milk banks can improve their screening processes by providing information up-front and ensuring timely contact with mothers. Mothers can then make informed decisions about donating and not feel as if their milk and resources are "wasted."

Donor and recipient safety in human milk banking.

AIM: Australian Red Cross Lifeblood supplies pasteurised donor human milk (PDHM) to more than 30 partner hospitals across Australia. Preterm infants who receive PDHM are a highly vulnerable population but formal biovigilance programs are rare in human milk banking. Lifeblood Milk performs ongoing surveillance for both donor and recipient adverse events. This study aimed to formally review adverse events reported to Lifeblood Milk since 2018. METHODS: Milk donor infectious diseases testing outcomes and donor adverse events (DAEs) are prospectively recorded at Lifeblood. Infant recipient adverse events are contractually reported back to Lifeblood Milk by hospitals and assessed according to severity and likelihood of relationship to PDHM administration. Donor and recipient adverse events over a 3.5-year period (July 2018 to December 2021) were reviewed. RESULTS: There were three DAEs (3/976 = 0.31%) related to phlebotomy; these included two vasovagal reactions and one phlebotomy site haematoma. Eight (8/976 = 0.81%) additional donors had biological false reactive (BFR) infectious diseases serology results. There were 10 reported suspected adverse events in recipients. Six were infection-related; other events included milk curd obstruction, high urinary iodine levels, sudden cardiac death and nasogastric tube obstruction. All reported suspected adverse events in recipients were classified as unlikely to be related, or definitely not related, to PDHM administration. CONCLUSIONS: Milk donor adverse events were rare but biological false reactive serology results were not uncommon. There were no recipient adverse events considered causally related to pasteurised donor human milk, which is generally a low-risk biological product. Ongoing biovigilance remains essential.

Virology and immune dynamics reveal high household transmission of ancestral SARS-CoV-2 strain.

BACKGROUND: Household studies are crucial for understanding the transmission of SARS-CoV-2 infection, which may be underestimated from PCR testing of respiratory samples alone. We aim to combine the assessment of household mitigation measures; nasopharyngeal, saliva, and stool PCR testing; along with mucosal and systemic SARS-CoV-2-specific antibodies, to comprehensively characterize SARS-CoV-2 infection and transmission in households. METHODS: Between March and September 2020, we obtained samples from 92 participants in 26 households in Melbourne, Australia, in a 4-week period following the onset of infection with ancestral SARS-CoV-2 variants. RESULTS: The secondary attack rate was 36% (24/66) when using nasopharyngeal swab (NPS) PCR positivity alone. However, when respiratory and nonrespiratory samples were combined with antibody responses in blood and saliva, the secondary attack rate was 76% (50/66). SARS-CoV-2 viral load of the index case and household isolation measures were key factors that determine secondary transmission. In 27% (7/26) of households, all family members tested positive by NPS for SARS-CoV-2 and were characterized by lower respiratory Ct values than low transmission families (Median 22.62 vs. 32.91; IQR 17.06-28.67 vs. 30.37-34.24). High transmission families were associated with enhanced plasma antibody responses to multiple SARS-CoV-2 antigens and the presence of neutralizing antibodies. Three distinguishing saliva SARS-CoV-2 antibody features were identified according to age (IgA1 to Spike 1, IgA1 to nucleocapsid protein (NP)), suggesting that adults and children generate distinct mucosal antibody responses during the acute phase of infection. CONCLUSION: Utilizing respiratory and nonrespiratory PCR testing, along with the measurement of SARS-CoV-2-specific local and systemic antibodies, provides a more accurate assessment of infection within households and highlights some of the immunological differences in response between children and adults.

Short-course intravenous antibiotics for young infants with urinary tract infection.

OBJECTIVE: Shorter courses of intravenous antibiotics for young infants with urinary tract infection (UTI) have myriad advantages. As practice shifts toward shorter intravenous treatment courses, this study aimed to determine the safety of early intravenous-to-oral antibiotic switch and identify risk factors for bacteraemia with UTI. METHODS: Retrospective audit of infants aged ≤90 days with a positive urine culture at a quaternary paediatric hospital over 4 years (2016-2020). Data were collected from the hospital electronic medical record and laboratory information system. Short-course intravenous antibiotic duration was defined as <48 hours for non-bacteraemic UTI and <7 days for bacteraemic UTI. Multivariate analysis was used to determine patient factors predicting bacteraemia. RESULTS: Among 427 infants with non-bacteraemic UTI, 257 (60.2%) were treated for <48 hours. Clinicians prescribed shorter intravenous courses to infants who were female, aged >30 days, afebrile and those without bacteraemia or cerebrospinal fluid pleocytosis. Treatment failure (30-day UTI recurrence) occurred in 6/451 (1.3%) infants. All had non-bacteraemic UTI and one received <48 hours of intravenous antibiotics. None had serious complications (bacteraemia, meningitis, death). Follow-up audiology occurred in 21/31 (68%) infants with cerebrospinal fluid pleocytosis, and one had sensorineural hearing loss. Bacteraemia occurred in 24/451 (5.3%) infants, with 10 receiving <7 days intravenous antibiotics with no treatment failure. Fever and pyelonephritis were independent predictors of bacteraemia. CONCLUSION: Short-course intravenous antibiotics for <48 hours for young infants with non-bacteraemic UTI should be considered, provided meningitis has been excluded. Treatment failure and serious complications were rare in young infants with UTI.

Comparison of Seroconversion in Children and Adults With Mild COVID-19.

Importance: The immune response in children with SARS-CoV-2 infection is not well understood. Objective: To compare seroconversion in nonhospitalized children and adults with mild SARS-CoV-2 infection and identify factors that are associated with seroconversion. Design, Setting, and Participants: This household cohort study of SARS-CoV-2 infection collected weekly nasopharyngeal and throat swabs and blood samples during the acute (median, 7 days for children and 12 days for adults [IQR, 4-13] days) and convalescent (median, 41 [IQR, 31-49] days) periods after polymerase chain reaction (PCR) diagnosis for analysis. Participants were recruited at The Royal Children's Hospital, Melbourne, Australia, from May 10 to October 28, 2020. Participants included patients who had a SARS-CoV-2-positive nasopharyngeal or oropharyngeal swab specimen using PCR analysis. Main Outcomes and Measures: SARS-CoV-2 immunoglobulin G (IgG) and cellular (T cell and B cell) responses in children and adults. Seroconversion was defined by seropositivity in all 3 (an in-house enzyme-linked immunosorbent assay [ELISA] and 2 commercial assays: a SARS-CoV-2 S1/S2 IgG assay and a SARS-CoV-2 antibody ELISA) serological assays. Results: Among 108 participants with SARS-CoV-2-positive PCR findings, 57 were children (35 boys [61.4%]; median age, 4 [IQR, 2-10] years) and 51 were adults (28 women [54.9%]; median age, 37 [IQR, 34-45] years). Using the 3 established serological assays, a lower proportion of children had seroconversion to IgG compared with adults (20 of 54 [37.0%] vs 32 of 42 [76.2%]; P < .001). This result was not associated with viral load, which was similar in children and adults (mean [SD] cycle threshold [Ct] value, 28.58 [6.83] vs 24.14 [8.47]; P = .09). In addition, age and sex were not associated with seroconversion within children (median age, 4 [IQR, 2-14] years for both seropositive and seronegative groups; seroconversion by sex, 10 of 21 girls [47.6%] vs 10 of 33 boys [30.3%]) or adults (median ages, 37 years for seropositive and 40 years for seronegative adults [IQR, 34-39 years]; seroconversion by sex, 18 of 24 women [75.0%] vs 14 of 18 men [77.8%]) (P > .05 for all comparisons between seronegative and seropositive groups). Symptomatic adults had 3-fold higher SARS-CoV-2 IgG levels than asymptomatic adults (median, 227.5 [IQR, 133.7-521.6] vs 75.3 [IQR, 36.9-113.6] IU/mL), whereas no differences were observed in children regardless of symptoms. Moreover, differences in cellular immune responses were observed in adults compared with children with seroconversion. Conclusions and Relevance: The findings of this cohort study suggest that among patients with mild COVID-19, children may be less likely to have seroconversion than adults despite similar viral loads. This finding has implications for future protection after SARS-CoV-2 infection in children and for interpretation of serosurveys that involve children. Further research to understand why seroconversion and development of symptoms are potentially less likely in children after SARS-CoV-2 infection and to compare vaccine responses may be of clinical and scientific importance.

Children and Adults in a Household Cohort Study Have Robust Longitudinal Immune Responses Following SARS-CoV-2 Infection or Exposure.

Children have reduced severity of COVID-19 compared to adults and typically have mild or asymptomatic disease. The immunological mechanisms underlying these age-related differences in clinical outcomes remain unexplained. Here, we quantify 23 immune cell populations in 141 samples from children and adults with mild COVID-19 and their PCR-negative close household contacts at acute and convalescent time points. Children with COVID-19 displayed marked reductions in myeloid cells during infection, most prominent in children under the age of five. Recovery from infection in both children and adults was characterised by the generation of CD8 TCM and CD4 TCM up to 9 weeks post infection. SARS-CoV-2-exposed close contacts also had immunological changes over time despite no evidence of confirmed SARS-CoV-2 infection on PCR testing. This included an increase in low-density neutrophils during convalescence in both exposed children and adults, as well as increases in CD8 TCM and CD4 TCM in exposed adults. In comparison to children with other common respiratory viral infections, those with COVID-19 had a greater change in innate and T cell-mediated immune responses over time. These findings provide new mechanistic insights into the immune response during and after recovery from COVID-19 in both children and adults.

Adding saliva testing to oropharyngeal and deep nasal swab testing increases PCR detection of SARS-CoV-2 in primary care and children.

OBJECTIVE: To compare the concordance and acceptability of saliva testing with standard-of-care oropharyngeal and bilateral deep nasal swab testing for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in children and in general practice. DESIGN: Prospective multicentre diagnostic validation study. SETTING: Royal Children's Hospital, and two general practices (cohealth, West Melbourne; Cirqit Health, Altona North) in Melbourne, July-October 2020. PARTICIPANTS: 1050 people who provided paired saliva and oropharyngeal-nasal swabs for SARS-CoV-2 testing. MAIN OUTCOME MEASURES: Numbers of cases in which SARS-CoV-2 was detected in either specimen type by real-time polymerase chain reaction; concordance of results for paired specimens; positive percent agreement (PPA) for virus detection, by specimen type. RESULTS: SARS-CoV-2 was detected in 54 of 1050 people with assessable specimens (5%), including 19 cases (35%) in which both specimens were positive. The overall PPA was 72% (95% CI, 58-84%) for saliva and 63% (95% CI, 49-76%) for oropharyngeal-nasal swabs. For the 35 positive specimens from people aged 10 years or more, PPA was 86% (95% CI, 70-95%) for saliva and 63% (95% CI, 45-79%) for oropharyngeal-nasal swabs. Adding saliva testing to standard-of-care oropharyngeal-nasal swab testing increased overall case detection by 59% (95% CI, 29-95%). Providing saliva was preferred to an oropharyngeal-nasal swab by most participants (75%), including 141 of 153 children under 10 years of age (92%). CONCLUSION: In children over 10 years of age and adults, saliva testing alone may be suitable for SARS-CoV-2 detection, while for children under 10, saliva testing may be suitable as an adjunct to oropharyngeal-nasal swab testing for increasing case detection.

COVID-19 public health measures and respiratory viruses in children in Melbourne.

AIM: To describe the epidemiology of respiratory viruses in children before and during the 2020 SARS-CoV-2 pandemic and the relationship to public health measures instituted by the Victorian government. METHODS: Retrospective audit of respiratory viruses at a tertiary paediatric hospital in Melbourne from January 2015 up to week 47, 2020 in children under 18 years of age. The proportion of positive cases in weeks 1-47 in 2015-2019 (period 1) were compared to weeks 1-47, 2020 (period 2), and reviewed in the context of public health restrictions in Victoria. RESULTS: An annual average of 4636 tests were performed in period 1 compared to 3659 tests in period 2. Proportions of positive influenza A virus, influenza B virus, respiratory syncytial virus (RSV) and human parainfluenza virus were significantly reduced in period 2 compared to period 1: 77.3, 89.4, 68.6 and 66.9% reductions, respectively (all P < 0.001). From week 12-47, 2020, 28 893 SARS-CoV-2 tests were performed with a 0.64% positivity rate. Influenza viruses were not detected after week 17, RSV was not detected after week 35. CONCLUSIONS: Strict public health measures and border closures were successful in eliminating community transmission of SARS-CoV-2 in Melbourne. This was associated with a significant reduction in other respiratory virus infections in children. Identifying sustainable and effective ongoing public health interventions to reduce transmission of RSV and influenza could result in reduced morbidity and mortality in children and requires further research.

Innate cell profiles during the acute and convalescent phase of SARS-CoV-2 infection in children.

Children have mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) confirmed disease (COVID-19) compared to adults and the immunological mechanisms underlying this difference remain unclear. Here, we report acute and convalescent innate immune responses in 48 children and 70 adults infected with, or exposed to, SARS-CoV-2. We find clinically mild SARS-CoV-2 infection in children is characterised by reduced circulating subsets of monocytes (classical, intermediate, non-classical), dendritic cells and natural killer cells during the acute phase. In contrast, SARS-CoV-2-infected adults show reduced proportions of non-classical monocytes only. We also observe increased proportions of CD63+ activated neutrophils during the acute phase to SARS-CoV-2 in infected children. Children and adults exposed to SARS-CoV-2 but negative on PCR testing display increased proportions of low-density neutrophils that we observe up to 7 weeks post exposure. This study characterises the innate immune response during SARS-CoV-2 infection and household exposure in children.

Maintaining human milk bank services throughout the COVID-19 pandemic: A global response.

If maternal milk is unavailable, the World Health Organization recommends that the first alternative should be pasteurised donor human milk (DHM). Human milk banks (HMBs) screen and recruit milk donors, and DHM principally feeds very low birth weight babies, reducing the risk of complications and supporting maternal breastfeeding where used alongside optimal lactation support. The COVID-19 pandemic has presented a range of challenges to HMBs worldwide. This study aimed to understand the impacts of the pandemic on HMB services and develop initial guidance regarding risk limitation. A Virtual Collaborative Network (VCN) comprising over 80 HMB leaders from 36 countries was formed in March 2020 and included academics and nongovernmental organisations. Individual milk banks, national networks and regional associations submitted data regarding the number of HMBs, volume of DHM produced and number of recipients in each global region. Estimates were calculated in the context of missing or incomplete data. Through open-ended questioning, the experiences of milk banks from each country in the first 2 months of the pandemic were collected and major themes identified. According to data collected from 446 individual HMBs, more than 800,000 infants receive DHM worldwide each year. Seven pandemic-related specific vulnerabilities to service provision were identified, including sufficient donors, prescreening disruption, DHM availability, logistics, communication, safe handling and contingency planning, which were highly context-dependent. The VCN now plans a formal consensus approach to the optimal response of HMBs to new pathogens using crowdsourced data, enabling the benchmarking of future strategies to support DHM access and neonatal health in future emergencies.

A case report describing the immune response of an infant with congenital heart disease and severe COVID-19.

Background: Children with SARS-CoV-2 infection generally present with milder symptoms or are asymptomatic in comparison with adults, however severe disease occurs in a subset of children. To date, the immune correlates of severe COVID-19 in young children have been poorly characterised. Methods: We report the kinetics of immune responses in relation to clinical and virological features in an infant with acute severe COVID-19 using high-dimensional flow cytometry and multiplex cytokine analysis. Results: Systemic cellular and cytokine profiling show an initial increase in neutrophils and monocytes with depletion of lymphoid cell populations (particularly CD8 + T and NK cells) and elevated inflammatory cytokines. Expansion of memory CD4 + T (but not CD8 + T) cells occurred over time, with a predominant Th2 bias. Marked activation of T cell populations observed during the acute infection gradually resolved as the child recovered. Substantial in vitro activation of T-cell populations and robust cytokine production, in response to inactivated SARS-CoV-2 stimulation, was observed 3 months after infection indicating durable, long-lived cellular immune memory. Conclusions: These findings provide important insights into the immune response of a young infant with severe COVID-19 and will help to inform future research into therapeutic targets for high-risk groups.

What are Optimal Bacteriological Screening Test Cut-Offs for Pasteurized Donor Human Milk Intended for Feeding Preterm Infants?

BACKGROUND: Definitive criteria for microbial screening of pasteurized donor human milk are not well established and international recommendations vary. AIMS: (1) To review pasteurized donor human milk batch discard due to failed microbial screening criteria at our milk bank (following United Kingdom National Institute of Clinical Excellence guidelines), and (2) to compare our known milk discard proportion with estimated milk discard proportions that would be required by other international milk bank guidelines. METHODS: We reviewed our microbial screening results (N = 783) over 18-months (July 2018-December 2019) and compared our known milk discard proportion with estimated milk discard proportions using other international milk bank guidelines. RESULTS: Of samples, n = 50 (6.4%) failed pre-pasteurization screening, most commonly due to the presence of >104 CFU/mL Enterobacterales in the pre-pasteurization sample (n = 30; 3.8%). Two (0.3%) samples failed post-pasteurization screening, with Bacillus cereus identified in both cases, resulting in total discard proportion of 6.7% (n = 52) of batches. Applying European Milk Bank Association recommended bacterial screening criteria, approximately 23.3% (n = 183) of milk batches would have been discarded. CONCLUSIONS: Further research is required to justify the stringent European Milk Bank Association recommendations for pre-pasteurization discard criteria, although we believe that a post-pasteurization acceptance criterion of <1 CFU/mL is appropriate and aligns with international guidance. Further work is needed to understand pasteurized donor human milk microbiological safety risks, to better integrate screening criteria within current food standards regulation, and to consider risk-based assessment including the impact on availability and affordability.