updated 21 September 2021
Australian collected data updated to 13 September 2021 was used to extrapolate the case fatality rates (CFR) for children aged under 12 (<12s).
The extrapolated CFRs were reduced by 0.013/0.04 because the current all age CFR in this this (NSW) wave appears to be 0.013, whereas the all age CFR of the collected data is 0.04 (probably reflecting the improvement in treatment and resources over time.
It may be that this reduction based on the difference in CFRs during the two waves is unnecessary because the high CFR of 4% during wave 2 (Vic) was due to clusters in aged care prior to a vaccine being available. The age specific CFRs may not have changed.
The childhood estimates of CFR are likely conservative and represent minimum values.
Childhood CFRs were extrapolated from a linear relationship between the log of the CFR and the Mean Age of the Cases and Deaths because that gave the lowest estimates of the CFR.
The extrapolations suggested that the likely minimum risk of dying from Covid19 unvaccinated was
31 in a million for ages 0 to 4
49 in a million for ages 5 to 9
and 68 in a million for ages 10 to 11.
The overall CFR for <12s was 45 in a million.