496 - Are COVID-19 infections or vaccinations associated with an altered macronutrient composition of human milk (HM)?

Poster Number: 496
Publication Number: 496.1980

Background: HM is the standard of infant nutrition, providing a complex array of nutrients and other components essential for growth and development. However, the interplay between maternal health, viral infections, vaccination, and the composition of HM remains less known. The COVID-19 pandemic introduced unprecedented challenges to maternal-infant health, including breastfeeding. Whereas HM provided by a mother with a COVID-19 diagnosis does not transmit the virus, it is unknown whether maternal COVID-19 infection or vaccination alters the macronutrient composition of HM.

Objective: As COVID-19 transitions to an endemic phase, we sought to investigate whether COVID-19 infection or vaccination influences the macronutrient content of HM.

Design/Methods: Mothers’ Milk Bank at Austin (MMBA) screened and approved milk donations from lactating mothers throughout the pandemic regardless of their experience with COVID-19 vaccines or infection, as long as the mothers were not taking prohibited medications. MMBA collected medical and lifestyle histories from 800 HM donors. Data included: date of vaccination(s) (J&J, Pfizer, & Moderna), any COVID-19 diagnoses or exposures, and reports of COVID-19 symptoms but no confirmed diagnosis. The macronutrient composition of deposits of donated human milk (DHM) was measured by Foss Electric’s FT120 Milkoscan routinely as required by milk processing prior to targeted pooling, and included total lactose, fat, and protein content. In addition to reported COVID-19 experiences (vaccinations, diagnoses, exposures, symptoms), the lactational age of the DHM samples, gestational age at birth and maternal age were included in the analysis.

Results: Approximately 21% of DHM came from mothers who delivered before 36 weeks (median lactational age 44.1 [IQR 21.4 - 77.0]). Lactational age was significantly higher in HM deposits with COVID-19 overlap than vaccination overlap and no overlap (Table 2). Macronutrients were higher in preterm milk (data not shown), and heavily influenced by lactational age. A mixed effects model approach was taken to investigate COVID-19 overlap while accounting for lactational age, preterm milk, and multiple observations. A fixed increase of 0.02 g/dL (95% CI 0.00 - 0.04) on protein was significant in HM deposits with any COVID-19 experience overlap (Table 3).

Conclusion(s): COVID-19 infection or vaccination does not alter the macronutrient content of expressed donated HM, except for minor increases in protein content. Understanding the relationship between HM and COVID-19 will help healthcare professionals and parents to make informed decisions about breastfeeding.