I promised an update, so here it is.
Cases. South Africa has seen a continued dramatic increase in case. Now at over 10,000 a day, with the last two weeks having week over week increases at around 3x. This means when you go back 3 weeks they had around 300 a day (see very good South African CDC equivalent site here: South African NICD). In South Africa, these increases exceed the rate of increase at any time during the pandemic, going all the way back to March 2020. Until now, the largest sustained (lasting at least a week) weekly increase was 138%. For Omicron in the last week, it was 255%. Not good!
Hospitalizations. These have seen a dramatic increase also, but less dramatic than cases. While hospitalizations lag cases (happen a few days after, on average), we have enough data to say with some confidence that their increase will not be AS dramatic. Unfortunately that is not saying much, but it does indicate the combination of prior infection (larger percentage) and vaccines (smaller percentage) is probably helping with serious cases, if not infections.
How does this translate the US?
Two issues affect this.
Vaccine effectiveness. South Africa has a very low vaccination rate (~25%) so we will need data from labs (coming out soon) to really start to answer that, and after that (hopefully within a few weeks) we will have real world data, but we need a lot of infections to really answer it because hospitalizations are rare with Covid. It seems widely agreed that vaxes will prevent serious disease to some extent, but the question is will they be 90+ effective or something below that, and if below that, how far below? Regarding just infection, I dont hold out much hope they will be very effective, at least not without a booster, but even 50% effective will of course help.
If/when Omicron will become dominant. There's still a chance Omicron will never become dominant here, merely because of the huge number of delta infections we have (it may crowd out Omicron). However, if the huge transmission advantage it seems to have in South Africa holds up, it will eventually dominate here. Simple modeling indicates it will be awhile, likely February or after. That would buy some time. By February, we will almost certainly have the new Covid pills (from Pfizer) widely available (and they very likely will work with Omicron).
Also, an Omicron-specific booster, if needed, will likely be available in March.
Finally, I also hold out hope (which I've been holding out since April 2020) that we will finally deploy at-home tests widely--this could help considerably in curbing transmission. Even though Omicron is highly contagious, testing before going to larger gatherings and visits with older people can have a big impact--much of Covid's spread continues to be at larger events and most of the deaths are among 65+. Readily available (and free) at-home tests seem like they are almost here--we could even start doing it at the event itself (and at airports), or is that too optimistic?
So, net-net, we're still in a wait and see mode, but we will likely have a little time to figure this out before we are really hit hard, and we do have some new weapons at our disposal.