Which is more likely to happen-antigenic DRIFT,or antigenic SHIFT-and why?

Question

Quizplus · Accepted Answer

Antigenic drift is more likely to happen as it occurs due to random mutations that happen as the virus replicates in the infected person's cells. Since infection with only a single virus is required, and random mutations occur more readily when only one virus is infecting a cell at a given time, antigenic drift is more likely to occur. On the other hand, antigenic shift requires the co-infection of multiple viruses in a cell at once, which is less common. Additionally, while the larger RNA polymerase pool may increase the likelihood of mistakes, it does not necessarily mean that antigenic shift is more likely.

Which Is More Likely to Happen-Antigenic DRIFT,or Antigenic SHIFT-And Why