It means that if (big ifs!) (a) the South African peak is truly a peak and (b) vaccine-acquired immunity staves off severe illness to the same extent that infection-acquired immunity does[*], Europe is not in for “quite a ride.” As in South Africa, cases will briefly peak at a very high level, but without a corresponding high level of hospitalizations or deaths.

[*] while only ~30% of SA’s population has been vaccinated, some estimate an additional 40% of the population have been infected, for an overall immunity rate of ~70%, which is comparable to the vaccination rate in the US/Europe.