The bitter dispute between the UK and European Union over AstraZeneca's COVID-19 vaccine has led to a new and for some, life-threatening, trend: vaccine nationalism. 

Even U.S President Joe Biden isn't immune to criticism that his America First strategy risks endangering supplies - especially to poorer countries.

They are supposed to be the staunchest of allies. But as the European Union, Great Britain and United States race to vaccinate, bitter divisions are erupting between them.

This dispute over who’s first in line is driving a trend dubbed #vaccinenationalism