Vaccines are the most effective means available for preventing infectious diseases. However, vaccine-induced immune responses are highly variable between individuals and between populations in different regions of the world. Understanding the basis of this variation is, thus, of fundamental importance to human health. Although the factors that are associated with intra- and inter-population variation in vaccine responses are manifold, emerging evidence points to a key role for the gut microbiome in controlling immune responses to vaccination. Much of this evidence comes from studies in mice, and causal evidence for the impact of the microbiome on human immunity is sparse. However, recent studies on vaccination in subjects treated with broad-spectrum antibiotics have provided causal evidence and mechanistic insights into how the microbiota controls immune responses in humans.

疫苗是预防传染病的最有效手段。但是，疫苗诱导的免疫反应在世界不同地区的个体之间以及人群之间变化很大。因此，了解这种变化的基础对人类健康至关重要。尽管与疫苗接种过程中种群内和种群间变异相关的因素是多种多样的，但新出现的证据指出了肠道微生物组在控制对疫苗免疫反应方面的关键作用。这些证据大部分来自小鼠的研究，而微生物组对人类免疫力影响的因果证据很少。然而，