Babies that are born extremely prematurely are at higher risk of developing a serious inflammatory condition, called necrotizing enterocolitis (NEC), that damages parts of the intestines. It is the most common cause of illness of the intestinal tract in premature infants in the first few weeks of life. It is a very serious condition that can lead to death in up to half of affected infants.The main purpose of this study is to see if IBP-9414 ( a probiotic) can prevent NEC and if it is safe and tolerable.

IBP-9414 (Lactobacillus reuteri) is a live bacterial therapy given to infant's through a feeding tube or it is given by mouth once daily starting at or before 48 hours of life. IBP-9414 will be given daily until the infant reaches 34 weeks + 6 days Post-Menstrual Age (PMA) (the the baby's gestational age at birth plus the postnatal days of life), or until treatment is permanently discontinued if earlier.

Participants who test positive for COVID-19 at MUSC/affiliate virtual care testing venues, but who do not require hospitalization, will be approached to be randomized to a placebo or a bolus of oral vitD3 (20,000 IUX3d) followed by 6000 IU vitD3/day for 12 months. All participants will receive a multivitamin containing 1000 IU vitD3. Study groups will be compared on the basis of 25(OH)D concentration and subsequent COVID-19, symptom severity, need and duration of hospitalization (LOS), admission to the ICU, ventilatory support, and mortality, return to usual daily activities and/or work, as a function of age, BMI, and other recognized COVID-19 risk factors.

Participants who test negative for COVID-19 at MUSC/affiliate virtual care testing venues, will be approached to be randomized to a placebo or 6000 IU vitD3/day for 12 months. All participants will receive a multivitamin containing 1000 IU vitD3. Study groups will be compared on the basis of 25(OH)D concentration, COVID-19 antibody titers, and the number who become COVID-19 positive during the course of the study, as well as severity of illness using validated symptom questionnaires, need for hospitalization, duration of acute symptoms, return to typical daily activities and/or work.

Participants in Aim 3 will be obtained from MUSC Biorepository of Covid+ subjects who were hospitalized and recovered; stored plasma will be used to measure vitamin D and cytokines. If subjects agreed to recontact, will be called to see if interested in participating in Aim 3; after eConsent, will be followed for one year with 5 virtual visits.

The protocol is for the full study, with numbers of participants for this pilot in parentheses. We have funding for the pilot with the UDAK in this application. We are continuing to search for funding for the full study, and the science is powered for the full study. When we receive funding for the full study, we will submit an amendment to increase the intended participant numbers.

Breastfeeding is important for the development of the immune system of the infant. Emerging data suggest that vitamin D plays an important role in immunity as well. Exclusively breastfeeding mothers and their infants will be studied in a 3-month (4-study visit) pilot study of vitamin D supplementation versus placebo. Longitudinal effects of vitamin D status on breast milk composition and on the infant's immune system will be examined.
Additionally, exclusively breastfeeding mothers who are currently on vitamin D supplementation will be studied at a single visit, at which mothers will provide a single breastmilk sample and have a single blood sample obtained. These samples will be used to examine effects of vitamin D supplementation on breast milk composition.