Neonatal vitamin A supplementation mechanistic studies
WHO Technical consultation
9 - 10 September 2013
WHO/HQ Geneva, Switzerland, Salle G (8th Floor)
Scope and purpose
In 2008, a WHO Technical consultation on neonatal vitamin A supplementation research priorities recognized the need to study the biological mechanisms that may explain the potential effects of vitamin A supplementation in the first days of life, focusing on improved immune responses and organ maturation. Following this consultation, WHO received funds from the Bill & Melinda Gates Foundation to conduct three studies to understand the biological mechanisms through which neonatal vitamin A supplementation can potentially have an impact on infant survival when given at birth. The specific objectives of the studies are:
- To understand how a large dose of vitamin A given on the first day of life is absorbed, transported and distributed in body tissues.
- To determine if a large dose of vitamin A given early in life improves newborn vitamin A stores. If so, to understand the magnitude and duration of impact.
- To determine if a large dose of vitamin A given early in life affects organ maturation.
- To determine if a large dose of vitamin A given on the first day of life affects innate and adaptive immune responses.
Prior to the initiation of these studies in 2009, WHO held a Technical consultation on vitamin A in newborn health to finalize the study protocols, discuss current knowledge of vitamin A and immunology in infants and review the metabolism of vitamin A in early life.
One animal study using the sow-piglet dyad model was conducted by the University of Wisconsin to assess the efficacy of storage and distribution of graded oral doses of vitamin A in essential organs and detoxification mechanisms of vitamin A metabolism. Additionally, two human double-blind, placebo-controlled trials were conducted to determine the effect of neonatal vitamin A supplementation on immune responses in early infancy.
These studies examined the effect of 50 000 IU of vitamin A, given orally as a single dose within 48 hours of birth, followed by routine vaccinations, on immune function, including thymus maturation and function, systemic and mucosal immune responses to routine immunizations, regulation of immune responses and bacterial translocation. The studies were conducted in Azimpur, Dhaka, Bangladesh (n=305) and Sukuta, The Gambia (n=200).
The three studies have now been completed and the Evidence and Programme Guidance Unit (EPG) of the Department of Nutrition for Health and Development (NHD) is convening a Technical consultation in Geneva, Switzerland on 9 to 10 September 2013.
The main objectives of this Technical consultation are to:
- Present a draft of the systematic review of the current published evidence on mechanisms of action of neonatal vitamin A supplementation.
- Review the results of the three mechanistic studies that are available thus far.
- Summarize the findings to date and discuss future sample analyses that may contribute to overall body of evidence for neonatal vitamin A supplementation.
- Plan for future data analyses and publications.