The announcement comes as much of Europe is facing rising infection and hospital rates and concerns about the new omicron variant.
The EMA, together with the European Center for Disease Control, said that a mix-and-match strategy could give nations more options in vaccination campaigns as much of the continent faces rising infection and hospitalization rates.
“The evidence available so far with different types of authorized vaccines indicates that a heterologous booster appears as good as or better in terms of immune responses than a homologous booster,” the agencies said in a statement.