Two new fast-spreading subvariants of Omicron are causing fresh surges of Covid around the world.
BA.4 and BA.5 emerged in South Africa and may soon become the dominant strains in Europe and the US, health experts say.
BA.4 and BA.5 Omicron are not thought to be any more lethal than other types of Covid.
Lots of people have built up some immunity from past infections and vaccination, which is helping to make the disease less risky overall.
But the new subvariants do appear to be spreading more easily.
