As that article notes, flu shots have a similar regulatory regime:
> And some scientists say health officials know enough about how vaccines work to start handling the COVID-19 vaccines like the flu vaccines, which are changed every year to try to match whatever strains are likely to be circulating but aren't routinely tested again every year.
and that the new vaccine still expresses the original proteins the already-approved vaccinations were expressing; in the worst-case scenario that mice and humans react similarly to Alpha/Delta but wildly differently to Omicron/BA.4/BA.5, we're still likely generating the at least the original immune response:
> The new booster will be identical to the original vaccines except it will contain genetic coding for two versions of the protein the virus uses to infect cells — the protein from the original vaccine and proteins from the BA.4 and BA.5 omicron subvariants.
A rapid approval process is going to be important for boosters, for the same reasons it is in flu shots. It's very clear the claim that it was only tested on eight mice is false.