The two new vaccines are mRNA vaccines.  This is a relatively new technology which basically takes part of the virus and uses it to create antibodies.  It is thought that the external or spike proteins of the new COVID-19 varient has not mutated, so it is still recognizable to the antibodies created by vaccination.   Moreover, the mRNA vaccine uses a polyclonal strategy, meaning that more than one feature of the virus is recognizable by host antibodies.  For now, we are okay, but getting COVID-19 under control with a mass immunization rollout is an imperative.