okay, here's a story - recent - suggesting Omicron may have mild effects in SA because so many citizens have already had Covid and it's provided them with some sort of immunity
https://www.dailymail.co.uk/news/article-10299773/South-Africas-Omicron-outbreak-slows-figures-suggest.html
That's sort of good news, but nobody seems to know yet how good the immunity is or how long it lasts. I don't plan on going there (lovely country - last time I was there Winnie Mandela gave me a wave as I went by), and personally I think I'd be cautious about taking in arrivals from there.
I have much more faith in Javid than in Boris, however, so I'll just have to hope he's right.