请教下面这个关于疫苗和病毒变异的观点， 怎么理解？ 多谢！

" in minutes from its July 7 meeting, SAGE scientists wrote that "the combination of high prevalence and high levels of vaccination creates the conditions in which an immune escape variant is most likely to emerge." It said at the time that "the likelihood of this happening is unknown, but such a variant would present a significant risk both in the UK and internationally."

https://www.cnn.com/2021/08/01/health/uk-scientists-covid-variant-beat-vaccines-intl/index.html