A-L-E-X wrote:Source of the post Wat, what happened to those variations that were supposed to be worse than Delta? One was Lambda I think and the other was Mu?
Outside of inflated media headlines, I don't think there was ever any serious prediction that they would be worse. They were never considered variants of concern, just of interest or monitoring.
There was limited evidence that they might be able to evade prior immunity or vaccines a little bit more than other variants. However, delta had the huge advantage in transmissibility, so delta quickly made up the vast majority of new cases. Now we have a large fraction of the population that is either vaccinated or recovered, so any variants have to either be extremely transmissible, extremely immune evading, or both, in order to continue to spread. Delta clearly has the former going for it, but the others don't evade immunity enough to be able to compete with it.
This is kind of a catch-22 with predicting the behavior of variants: we identify them when they show up often enough in sequenced cases, but then we can't really know their properties well until they demonstrate them by how they spread and compete with the others. It was because of how quickly delta outcompeted the other variants that we could tell it was so much more transmissible (though there were other hints from contact tracing). We couldn't just know that it would do that when it was first detected.