The first piece of good news is that this wave might be shorter lived than those of other variants. Every country is different, of course, with different population structures and different levels of immunity, both “natural” and from vaccination. But in South Africa, it appears that, while test positivity is still growing throughout the country, in the Omicron epicenter of Guateng the wave may be peaking already, with cases and hospital admissions both taking a visible turn, barely three weeks since the variant was first publicly announced and just five weeks since the first likely case. Guateng is not all of South Africa, of course, but a fast local peak still suggests the possibility of a very fast first wave. If the pattern holds and is replicated in the U.S., it could mean an American Omicron peak of cases sometime before the end of January.

But while this is much better than the alternative — a longer South African wave, with many more cases, reaching ultimately a much larger share of the population — it is also not necessarily a safe bet to be replicated elsewhere. In South Africa, it appears Omicron may now be peaking with only roughly as many recorded cases as were recorded at the peak of the country’s Delta wave; in the U.K., they have already broken their all-time record, and are heading way up from there. Perhaps this means that South Africa is vastly under-testing, and the true infection count is, in fact much higher — though this would be encouraging, too, since it suggests that an even larger proportion of total infections are too mild to register. But it could also mean that — perhaps because of population structure, perhaps because of differences in acquired immunity — we simply can’t extrapolate the South African experience to other countries. Two years into the pandemic, there is still an awful lot we don’t truly understand about the dynamics of disease spread and precisely why waves taper, peak, and decline, often well before reaching most vulnerable people. Time will tell, since if the U.K. is following the South African path we’d probably see that curve bending within a week or so.