In early 2023, when Omicron was the variant of concern, we showed that vaccinating pregnant women decreased the risk of severe COVID-19 related complications, and maternal morbidity and mortality. To analyze the impact of COVID-19 during pregnancy on newborns and the effects of maternal COVID-19 vaccination on neonatal outcomes, when Omicron was the variant of concern. INTERCOVID-2022 is a large, prospective, observational study, conducted in 40 hospitals across 18 countries, from November 27, 2021 (the day after the World Health Organization declared Omicron the variant of concern) to June 30, 2022, to assess the effect of COVID-19 in pregnancy on maternal and neonatal outcomes, as well as vaccine effectiveness (VE). Women diagnosed with laboratory-confirmed COVID-19 in pregnancy were compared with two 'non-diagnosed', unmatched women recruited concomitantly and consecutively in pregnancy or at delivery. Mother/newborn dyads were followed until hospital discharge. Primary outcomes were a neonatal positive test for COVID-19, severe neonatal morbidity index (SNMI), severe perinatal morbidity and mortality index (SPMMI), preterm birth, neonatal death, referral to neonatal intensive care unit (NICU), and diseases during the neonatal period. VE was estimated adjusted by maternal risk profile. We enrolled 4707 neonates born to 1577 (33.5%) mothers diagnosed with COVID-19 and 3130 (66.5%) non-diagnosed mothers. Amongst diagnosed mothers, 642 (40.7%) were not vaccinated, 147 (9.3%) were partially vaccinated, 551 (34.9%) were completely vaccinated, and 237 (15.0%) also had a booster vaccine. Neonates of booster-vaccinated mothers had less than half (RR=0.46; 95%CI=0.23, 0.91) the risk of being diagnosed with COVID-19 compared to those of unvaccinated mothers; they also had the lowest rates of preterm birth, medically-indicated preterm birth, respiratory distress syndrome and number of days in NICU. Newborns of unvaccinated mothers had double the risk of neonatal death (RR=2.06; 95% CI=1.06, 4.00) compared to those of non-diagnosed mothers. Vaccination was not associated with any congenital malformations. Although all vaccines provided protection against neonatal test positivity, newborns of booster-vaccinated mothers had the significantly highest VE (64%; 95% CI=10-86%); VE was not as high for mRNA vaccines only. VE against moderate/severe neonatal outcomes was much lower: 13% in the booster-vaccinated group (all vaccines), and 25% and 28% in the completely and booster-vaccinated groups, respectively (mRNA vaccines only). Vaccines were fairly effective in protecting neonates when given to pregnant women 100 days (14 weeks) or less before birth; thereafter, the risk increased and was much higher after 200 days (29 weeks).. Finally, none of the neonatal practices studied, including skin-to-skin contact and direct breastfeeding, increased the risk of infecting newborns. When Omicron was the variant of concern, newborns of unvaccinated mothers had an increased risk of neonatal death. Neonates of vaccinated mothers had a decreased risk of preterm birth and adverse neonatal outcomes. As the protective effect of COVID-19 vaccination decreases with time, to ensure that newborns are maximally protected against COVID-19 mothers should receive a vaccine or booster dose no more than 14 weeks before the expected date of delivery.

The nutritional adequacy of human milk (HM) from vegan/vegetarian mothers has been a matter of debate, and a variety of recommendations regarding the eligibility of these mothers as human milk donors exists. According to the latest evidence, HM from vegans/vegetarians is similar in its composition to that from omnivores, however, some differences may be observed regarding vitamin B₁₂ and omega‐3 fatty acids concentrations. Maternal supplementation of these compounds has been proven effective in increasing their HM concentration. With this survey, we aimed to explore the practices currently in use in European human milk banks (HMBs) regarding potential donors following vegan/vegetarian diets. The online survey was distributed to European HMBs between January and July 2022. A total of 188 HMBs were contacted, and 118 replied (response rate 63%). Vegan and vegetarian mothers were recommended supplements of vitamin B₁₂ to be accepted as donors in 27% and 26% of HMBs, respectively. Additional omega‐3 fatty acid supplementation was required in 8% HMBs. In the remaining HMBs, these mothers were either systematically excluded or included regardless of supplementation. The dosage of the recommended supplements was extremely variable. Fifty‐one percent of HMBs were following recommendations to guide their practice, national or local recommendations mainly. Great variability in European HMBs practices towards potential donors following vegan/vegetarian diets exists. Some of these practices can result in loss of donors and/or in potential nutritional deficiencies. Standardised evidence‐based recommendations on this issue and their implementation in daily HMB practice are needed.

When feeding at the breast is not possible, infants can still receive expressed mother's own milk (MOM). Method of expression, hygiene practices and settings during expression, and processing can affect MOM composition. to review current evidence on the influence of feeding expressed MOM using varying expression methods, varying hygiene practices or settings during expressions, or varying treatments on health and growth of recipient infants. we systematically searched CENTRAL, CINAHL, ClinicalTrials.gov, Embase, Emcare, EU trials, Global Health, Global Index Medicus, MEDLINE, Scopus, Web of Science, WHO, for primary research studies, including observational studies, published up to March 2024 evaluating different methods of MOM expression, hygiene practices or settings during expression, processing of MOM, and reporting clinical outcomes on recipient infants. Key outcomes of interest were growth, mortality, morbidity, feeding tolerance, adverse events, CMV infection, retroviral infection, other infections, nutrient deficiencies, neurodevelopment, breastfeeding. Qualitative thematic synthesis was conducted. An evidence gap map was produced using a GRADE evaluation. Of 29,320 studies screened, 45 met inclusion criteria. No expression method or pump type showed clear benefits for breastfeeding rates or infant growth. Three studies reported improved weight gain in infants receiving hindmilk. Evidence on the effect of processing methods on morbidity and mortality was inconclusive. Limited evidence was found on freeze-thawing's efficacy in reducing CMV transmission, while pasteurization proved more effective. No studies assessed clinical outcomes related to hygiene practices or expression settings. The use of hindmilk improves infant weight gain with some certainty of evidence. Hand expression of MOM has similar efficacy on the growth of recipient infants to that of electric pumping, also for mothers of preterm infants. Evidence on clinical outcomes of different MOM expression practices and treatments is very limited. This work underscores the need for future studies to address the substantial evidence gaps identified. REGISTRY AND REGISTRY NUMBER FOR SYSTEMATIC REVIEWS OR META-ANALYSES: The study was registered on PROSPERO (CRD42024523299). Previous reviews have focused on the effects handling practices for expressed mother's own milk, such as expression methods, hygiene practices/settings during expressions, and storage and processing treatments on the composition of MOM; however, changes in composition do not necessarily correspond to changes in clinical outcomes. To our knowledge, this is the only systematic review to evaluate the effects of these practices on a large number of clinically relevant outcomes (growth, main morbidities, feeding tolerance, adverse events, viral and retroviral infections, other infections, nutrient deficiencies, neurodevelopment, and breastfeeding) of recipient infants. In this context, the present work is important to identify gaps in knowledge, including methodological limitations of existing evidence, and guide future research.

Introduction Donor human milk (DHM) is the first alternative if mother’s own milk is unavailable or contraindicated. Much DHM research has focused on its nutritional, immunological and biochemical composition in response to various maternal variables, standard human milk banking procedures and storage protocols. The current systematic review protocol, however, aims to systematically gather and analyse existing data pertaining to the impact of these aforementioned factors on the clinical, health-related and developmental outcomes observed in infants fed with DHM. Methods and analysis We will apply a predefined search strategy including Cochrane Central Register of Controlled Trials, Global Index Medicus, CINAHL on Ebscohost, Medline, Embase, Emcare, Pubmed, Global Health on OVID, Google Scholar, clinicaltrials.gov, the WHO International Trials Registry and Platform and the European Union/European Economic Area Clinical Trials Register. No setting, patient population, date or language restrictions will be applied. The search strategy will consist of search words on the key concepts of ‘donated human milk’ and ‘effect on infants’. Published or unpublished primary research studies are eligible for inclusion if there is an abstract available in English. Conference proceedings, animal studies and publications with no original data will be excluded. Authors of unpublished or partially published studies will be contacted and eligible data added if provided. Risk of bias will be evaluated according to CASP using appropriate tools depending on study type (RoB 2, ROBINS-I, Newcastle Ottawa Scale). Data will be synthesised in a quantitative format describing significant results as well as presenting the results of the quality assessment of studies. Ethics and dissemination This systematic review does not require ethical approval, as we will not collect primary data. The review will be published in a peer-reviewed journal and disseminated electronically and in print. PROSPERO registration number CRD42024522015.

Introduction: Breastfeeding is the biological norm for infant nutrition. In certain scenarios, feeding at the breast is not possible, because of either maternal or neonatal reasons. In those cases, infants can still receive expressed mother’s own milk (MOM) and its beneficial properties. Mothers can express their milk using a variety of methods, while applying different hygiene practices, in different settings; moreover, expressed milk might receive processing before it is fed to the infant, particularly to reduce transmission of viruses such as cytomegalovirus to premature infants. The present protocol was designed to gather the evidence on the effect that the expression method, the hygiene regimen and setting and any processing used on expressed MOM can have on the clinical outcomes of recipient infants. Methods: This systematic review will follow the methodological recommendations of the Cochrane Collaboration, in accordance with WHO recommendations and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We will apply a hybrid search strategy, by combining structured database search with predefined snowballing searches. We will include primary research studies only, without restrictions on the type and including observational studies; no publication time, setting or language restriction will be applied, provided the abstract is available in English. Studies evaluating different methods of MOM expression, hygiene practices or settings during expression, processing of MOM and reporting clinical outcomes on recipient infants will be eligible. The searches have been planned to be performed in April–May 2024. Two reviewers will independently perform the reference screening, data extraction and risk of bias analysis of eligible studies, by using standardised tools specific for each study design. Quantitative and thematic narrative data synthesis will be performed and statistical heterogeneity between studies tested. Meta-analyses of extracted data will be performed where applicable. For relevant outcomes, certainty of the evidence will be tested by using the Grading of Recommendations Assessment, Development and Evaluation approach. Ethics and dissemination: Ethical approval is not required for this study since no original data will be collected. There is patient and public involvement throughout this research process. The results of this review will be disseminated through publication in a peer-reviewed journal and through conference presentations. Moreover, this systematic review will inform recommendations on milk banking of the WHO Department of Nutrition and Food Safety. PROSPERO registration number: CRD42024523299.

Objectives: To evaluate the association between parental ethnicity and respiratory outcomes in infants born before 34 weeks of gestation. Methods: Retrospective matched case-comparison study of inborn infants admitted to two London tertiary neonatal units between September 2022 and September 2025. Infants were included if both parents self-identified as Black (African or Caribbean) or White (British, Irish or Other) ethnicity. Clinical data were collected from electronic records. The primary outcome was the rate of bronchopulmonary dysplasia (BPD). Results: 394 infants (197 Black, 197 White) were matched by gestational age (GA). The Black cohort had higher rates of gestational diabetes (GDM) (20.5 vs. 7.6 %, p<0.001) and of being small for gestational age (SGA) (32.0 vs. 19.3 %, p=0.004). After adjustment for GA, GDM and SGA, infants of Black ethnicity had significantly lower odds of requiring mechanical ventilation (p=0.029) and of the composite outcome of BPD or death (p=0.04). When the Black cohort was divided into African (n=157) and Caribbean (n=40) infants, African ethnicity was associated with lower rates of BPD (p=0.011) and of BPD or death (p=0.014) compared with White ethnicity. Caribbean infants had the highest rates of mechanical ventilation (p=0.017) and use of inhaled nitric oxide (p=0.039), and longer durations of mechanical ventilation (p=0.003) and admission (p=0.047), but had similar odds of BPD or of BPD/death to White infants (p=0.98 and p=0.73, respectively). Conclusions: In this UK cohort of preterm infants, respiratory outcomes differed by ethnicity. Further work is needed to identify the genetic, environmental and structural drivers of these difference so that interventions can be appropriately targeted.