445,000 children have not been registered for a Covid vaccine.
The vast majority of them are aged between 5 and 11.
The Covid vaccine portal opened for 5 to 11 year olds just over three weeks ago.
The HSE says there are 482,000 children in this age-group.
Just 24 per cent have been registered to date - leaving 366,000 who haven't been signed up by their parents or guardians.
The portal's been open for 12 to 15 year olds since last August.
75 per cent of this age-group have been signed up for a vaccine - leaving 69,000 unregistered.
The take-up among 16 and 17 year olds has been much higher, at 92 per cent - with only 10,000 not signing up.