@Kevin27539603 @KawasakiKR11 And they could. There were tweaked versions for both Beta and Delta (and a bivalent version containing both) run in trials last year. Nobody in either governments or manufactures ever wanted to switch production.
@Kevin27539603 @KawasakiKR11 他们可以。去年，Beta 和 Delta（以及包含两者的二价版本）都有调整后的版本在试验中运行。无论是政府还是制造商，都没有人愿意改变生产。