Letter to the editor RE: Berendsen et al., 2016 ‘Non-specific Effects of Vaccines and Stunting: Timing May Be Essential’

Abstract

We read with great interest the article by Berendsen et al. [1] In this article, the authors aimed to evaluate the effect of timing of infant vaccination with Bacillus Calmette Gu erin (BCG), DTP1, and measles vaccine (MV) on stunting, among other outcomes. For this purpose, the authors retrospectively used secondary survey data on 368450 children from 33 Sub-Saharan African countries and, using logistic regression analyses, cross-sectionally performed mainly two types of analyses: 1. estimation of the odds of stunting in children with a past BCG, DTP1, and MV vaccination (separately) in comparison to unvaccinated children in overall and stratifying by the timing of vaccination 2. estimation of the odds of stunting in relation to a continuous variable for the timing of past vaccination with BCG, DTP1, and MV (separately). Stunting is defined as the impaired growth and development of children indicated by a considerably decreased height-for-age. Stunting has serious long-term effects on morbidity, mortality, and psycho-cognitive and social development. The condition is particularly important in Sub-Saharan Africa where the prevalence of stunting is alarmingly high. The findings of Berendsen et al. included lower odds of stunting in children who had a BCG vaccination early in life in comparison to children without BCG vaccination. However, the authors also reported paradoxically increased odds of stunting with BCG, DTP1, and MV vaccination later in infancy. Based on their study, the authors suggested that the timing of vaccination during infancy could sensitively have serious health implications with opposing effects on stunting when BCG vaccination was given during the first month of life (odds ratio [OR],