Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, 2300 Copenhagen, Denmark.
OPEN, Institute for Clinical Research, University of Southern Denmark/Odense University Hospital, 5000 Odense, Denmark.
Nutrients. 2019 Feb 21;11(2):449. doi: 10.3390/nu11020449.
A total of 12 trials have tested the effect of neonatal vitamin A supplementation (NVAS) on mortality. Overall, NVAS had no effect on mortality, but results were heterogeneous. Two competing hypotheses have been put forward to explain the divergent effects: A) NVAS works by preventing vitamin A deficiency (VAD) and not all countries have VAD; B) NVAS interacts negatively with subsequent diphtheria-tetanus-pertussis (DTP) vaccine, increasing mortality in females; in countries with low DTP coverage NVAS may have a beneficial effect. Only hypothesis A was tested in a recent meta-analysis; there is no strong empirical support for hypothesis A and it would not explain observed negative effects in some settings. Hypothesis B accounts for most observations. However, so far it has only been tested properly in a few trials. If hypothesis B is correct, it has major consequences for the understanding of the effects of vitamin A, and for the VAS policy in older children. As a WHO priority, the DTP coverage is bound to increase, and therefore hypothesis B urgently needs to be tested.
共有 12 项试验测试了新生儿维生素 A 补充（NVAS）对死亡率的影响。总体而言，NVAS 对死亡率没有影响，但结果存在异质性。为了解释这种不同的影响，提出了两个相互竞争的假设：A）NVAS 通过预防维生素 A 缺乏症（VAD）起作用，并非所有国家都存在 VAD；B）NVAS 与随后的白喉-破伤风-百日咳（DTP）疫苗产生负面相互作用，增加女性死亡率；在 DTP 覆盖率低的国家，NVAS 可能有有益的效果。最近的一项荟萃分析仅检验了假设 A；没有强有力的证据支持假设 A，也无法解释在某些情况下观察到的负面影响。假设 B 解释了大多数观察结果。然而，迄今为止，它仅在少数试验中得到了适当的检验。如果假设 B 是正确的，这将对理解维生素 A 的作用以及对年龄较大儿童的 VAS 政策产生重大影响。作为世卫组织的优先事项，DTP 覆盖率必然会增加，因此迫切需要检验假设 B。
