The BA.4 and BA.5 variants of Omicron have conquered Dunedin.
Viruses such as Covid-19 mutate over time, and following the initial surge of Covid cases in New Zealand, the increasingly more transmissible Delta and then Omicron variants have afflicted the country.
The largest outbreak of cases experienced so far was the initial Omicron wave, but the current explosion of cases across New Zealand has been driven by the emergence of several subvariants of Omicron, mainly BA.2, BA.4 and BA.5.
In early July, BA.4 and .5 overtook the BA.2 variant of Omicron to become the dominant strain, and BA.4 and BA.5 have since become the cause of more than 90 per cent of infections.