流感是重大的公共卫生问题，可发生全球大流行。研制安全有效的流感疫苗对控制流感至关重要。然而，由于流感病毒的交叉免疫及其机制尚未完全阐明，对研制疫苗带来不利影响。对甲型流感病毒交叉免疫的深入研究必将有助于更好地研制流感疫苗，对预防和控制甲型流感具有重要意义。此文对甲型流感病毒交叉免疫、免疫机制、不同亚型免疫的评价等研究进展进行综述。

Influenza is an important public health problem and occurs globally. Development of effective and safe influenza vaccines is vital to control and prevention of influenza.
However, cross-protective immunity to influenza A virus and its mechanisms are not completely elucidated, which results in some negative influences on vaccine development. Further studies on the cross-protective immunity will be helpful to reinforcing development of influenza vaccines, and prevention and control of influenza A. This article reviews research advances in cross-immunity to influenza A virus in animals and humans, cross-immunity mechanisms, and assessment of heterotypic immunity.