A child aged under one is among the Covid-19 cases in the Delta outbreak.
Dr Ashley Bloomfield told the Health Select Committee Tuesday afternoon after being questioned by National's Dr Shane Reti, who asked what the age of the youngest case was.
"Even from the data I've got from a few days ago, a breakdown on the first... 40 cases, our youngest case was aged under on," Dr Bloomfield said.
"Half the ages were under 20, think that age profile may well have changed since," Dr Bloomfield said.
The cases now far exceed 40 - today totaling 148 after 41 new cases were reported.
"At that point we had no cases who are Māori, but I understand there is at least once since then," Dr Bloomfield said.
Covid-19 Response Minister Chris Hipkins said the Delta variant was infecting younger populations "more readily than other variants of the virus and we're seeing that in our current response".
When asked today if thought had gone into pulling the vaccination eligibility for people aged 12 to 29 forward from September 1, Dr Bloomfield said the date would be remaining, but children aged 12-15 could get vaccinated with parents if they call the centres ahead of the appointment.