Commentary: Challenging public health orthodoxies—prophesy or heresy?†

In 1633, after many years of skirmishing with the Catholic Church over his support for Copernicus’ heliocentric theory of the universe, Galileo was finally sentenced by the inquisition to prison and religious penances. In a formal ceremony at the church of Santa Maria Sofia Minerva, he was forced to abjure his errors, and spent the rest of his life under house arrest in Sienna. The prophet had been convicted as a heretic. Without, yet, wishing to confer the status of prophet on Peter Aaby and his disciples based in Guinea Bissau, there are significant parallels in their persistent challenges to some of the deepest rooted public health orthodoxies of the present day. Aaby has a long history of interrogating datasets in a way that others have failed to do and coming up with some uncomfortable findings. For many years he has been in conflict with WHO and many vaccinologists concerning his beliefs that childhood vaccines can have non-specific downstream effects on mortality (sometimes positive, but often negative) that have been ignored by mainstream research. More recently his team have even challenged, on the basis of a randomized trial, the value of WHO’s recommendation that exclusive breastfeeding should continue to 6 months. Some may consider that house arrest is too lenient, even in Guinea Bissau instead of Sienna. Christine Stabell Benn, working within Aaby’s group, has for several years been pursuing another line of heresy, namely that it may be beneficial to withhold vitamin A supplementation (VAS) from infant girls in developing countries, at least until they have had their first measles vaccination. In this issue of IJE, the Bissau team summarize the evidence in support of their belief that co-administration of vitamin A with diphtheria–tetanus–pertussis vaccine (DTP) results in negative interactions that lead to higher subsequent mortality; an effect confined to girls. They then take this a step further by drawing on data from two very large trials of zinc and ironplus-folic-acid supplementation from Nepal and Zanzibar (Pemba). Using these data they argue that these trials also reveal important sex and agedifferential effects of preventive treatment with micronutrients with a ‘tendency’ for detrimental effects in infants especially among girls. They conclude that micronutrient supplementation policies might have to differ for boys and girls, and that in their view ‘all evidence suggests that currently infant girls have little to gain from micronutrients’. Could it really be true that in populations such as rural West Africa (where anaemia rates can exceed 90% and where 470% of young children can have plasma retinol levels <0.7 mmol/l), we can advocate that micronutrients should be withheld from girls? Is it really possible that marginal nutrient deficiencies might be protective where infections are highly prevalent, as recently postulated for iron? Only a few years ago such a view, which is in direct conflict with policy recommendations from WHO, the International Vitamin A Consultative Group (IVACG) and the International Nutritional Anemias Consultative Group (INACG), would have been condemned as heresy. However, the recent findings from the Pemba trial that supplementation with iron-plus-folic-acid caused a significant increase in serious adverse events and mortality leading to the trial’s termination by its Data and Safety Monitoring Board have brought a renewed humility, and a recognition that there can be complex interactions between micronutrients, pathogens and immunity. The state of our collective ignorance has been made painfully apparent. y A Commentary on: ‘Should infant girls receive micronutrient supplements?’ By Stabell Benn et al. (2008) * Corresponding author. MRC International Nutrition Group, London School of Hygiene & Tropical Medicine, London. E-mail: [email protected] 1 MRC International Nutrition Group, London School of Hygiene & Tropical Medicine, London. 2 MRC Keneba, The Gambia. The online version of this article has been published under an open access model. Users are entitled to use, reproduce, disseminate, or display the open access