The effect of supplementation with different combinations of probiotics, prebiotics (e.g., oligosaccharides), and/or lactoferrin on preterm infant mortality and morbidity.

The primary outcomes were the rates of severe necrotizing enterocolitis (NEC; a serious condition in preterm infants in which the intestinal tissue is inflamed and can die off, resulting in the release of its bacteria to the body, which can cause sepsis or systemic infection), NEC-related mortality, and all-cause mortality.

The secondary outcomes were sepsis rates, hospital stay length, and infant weight. Other outcomes were assessed, including feeding intolerances and the time to reach full enteral feeding (i.e., how long it took for the participants to stop intravenous nutrition).

The effect of supplementation with bovine lactoferrin on reported respiratory symptoms and systemic symptoms (primary outcomes).

The respiratory symptoms were throat discomfort, hoarseness, chest congestion, sneezing, runny nose, and plugged nose. The systemic symptoms were feeling feverish or unwell. All symptoms were scored on an 8-point Likert scale from 0 (no symptom) to 7 (severe symptom). The total scores of respiratory and systemic symptoms were calculated by summing the scores of individual symptoms.

The secondary outcomes were the expression of human leukocyte antigen-DR (HLA-DR) and cluster of differentiation 86 (CD86) on plasmacytoid dendritic cells (pDCs); these were assessed as markers of immune function.

The effect of different supplements on the risk of necrotizing enterocolitis (NEC; primary outcome) in preterm infants.

The secondary outcomes were the risk of sepsis and all-cause mortality, time to full feeding, and hospitalization duration.

The effect of lactoferrin on mouth and throat discomfort in low humidity.

The effect of bovine lactoferrin on COVID-19 severity in people hospitalized for the respiratory illness.