A new Omicron subvariant that's more transmissible and better at evading immunity is expected to trigger a winter wave sooner than expected.
Covid-19 cases of the BA.5 variant are roughly doubling every week and account for 15 to 20 percent of cases.
University of Auckland computational biologist David Welch says Aotearoa could return to similar daily infections as its March peak.
Dr Welch spoke to Morning Report.
