Determinants of responses to oral vaccines in developing countries

Abstract

Oral vaccines which are intended for global use do not necessarily induce the same immune responses in all children worldwide. In fact, several vaccines often induce less frequent and lower mean antibody responses in children in developing countries, suggesting that the vaccines may be less protective among children in these areas. Though the reasons for this less vigorous response are not completely understood, it appears that nutrition-related factors, including both protein-calorie and micronutrient malnutrition, are important aspects in understanding the hyporesponsiveness seen in these children. Related issues including breastfeeding, interference from maternal placental antibodies, intestinal parasitic infections, intestinal mucosal damage and possibly maternal malnutrition during pregnancy also appear to be important. Vaccines designed for oral administration will need to be adjusted to these potential problems in order to maximize benefits for all children. Oral vaccines, when given to children in developing countries, may require higher doses of vaccine, booster doses, calorie, micronutrient and vitamin supplements, withdrawal of breast milk before vaccine administration, deworming medications or other measures to realize their full benefit. Copyright © 2008 Nestec Ltd., Vevey/S. Karger AG.