Explainer: why are Covid infection rates in Australia so high compared with other countries?

PCR testing rates have dropped off in Australia but experts believe our testing rate is still likely higher than anywhere else in the world. Photograph: Joel Carrett/AAP

As three new Omicron subvariants – BA.2.12.1, BA.4 and BA.5 – begin to spread in Australia, health authorities are warning of winter surges in both Covid and the flu.

Reported Covid infection rates in Australia are already among the highest in the world. As of data from 2 May, Australia’s average daily infection rate is 1,515 cases per million people – the second-highest in the world for countries with a population greater than 1 million, after New Zealand (1,566 cases per million).