Half a million people in Northern Ireland have now received two doses of a Covid-19 vaccine.
The number of people who have received at least a first vaccine dose in Northern Ireland is expected to reach one million "imminently", said the health department.
Getting a second dose maximises protection from Covid-19.
Health Minister Robin Swann welcomed the announcement, which he said was "hugely encouraging".
He added that it meant people were "benefitting from the longer and stronger protection provided by second doses."
"It is vital that people keep coming forward for their first and second doses when their turn comes," he said.
No safety concerns
As the vaccination programme adjusts to take account of new advice around the use of the Oxford-AstraZeneca vaccine, it is expected the numbers being vaccinated will slow.
People aged under 40 in Northern Ireland who have yet to receive their first dose will be offered an alternative to the AstraZeneca jab, although people aged 30-39 can still get that jab through participating community pharmacies if they do not want to wait for an alternative to become available.
The Joint Committee on Vaccination and Immunisation (JCVI) has stated there were no safety concerns identified about blod clots and the second dose of AstraZeneca.
The Department of Health has launched a public information campaign to encourage uptake of the vaccine.
The health minister said the availability of both the AstraZeneca and Pfizer vaccines had played "a huge role" in the vaccination programme.