JOHANNESBURG — The detection of the Omicron variant in Africa signals the next stage of the battle against Covid-19: getting many more people inoculated in poorer nations where vaccines have been scarcest in order to deter new mutations from developing.

But while world leaders sometimes talk about this as if it were largely a matter of delivering doses overseas, the experience of South Africa, at least, hints at a far more complex set of challenges.

Like many poor countries, South Africa was made to wait months for vaccines as wealthier countries monopolized them. Many countries still do not have anywhere near enough doses to inoculate their populations.

As nations severed air links from southern Africa amid fears of another global surge of the coronavirus, scientists scrambled on Sunday to gather data on the new Omicron variant, its capabilities and — perhaps most important — how effectively the current vaccines will protect against it.

The early findings are a mixed picture. The variant may be more transmissible and better able to evade the body’s immune responses, both to vaccination and to natural infection, than prior versions of the virus, experts said in interviews.