The Stormont Executive announced on Wednesday it had agreed to roll out a Covid certificate system which would require proof of vaccination, a negative lateral flow test result or proof of past infection.
Programme head Patricia Donnelly said Northern Ireland is approaching 85% of the general population, and just under 90% of the adult population, being vaccinated.
The jab is currently being rolled out to those aged 12-15 in schools.
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Ms Donnelly said there was a significant surge of people turning up for their first dose of the vaccine from Wednesday.
“We had 1,000 people that we hadn’t expected turning up both yesterday (Thursday) and Wednesday to community pharmacies and some of the second dose clinics that trusts have been running,” she told the Nolan Show.
She said they were unexpected as uptake among younger age groups has been slow since the initial rush.
“It has been very slow to approach 55% of the 18 to 29-year-olds, it has been very very slow to get to 80% of the 30 to 39-year-olds. It has taken months and months,” she said.
“We had been used to a few hundred coming forward each week. We’ve had an unusual week in the last week in that we’ve had 1,000 come into community pharmacies, of all ages but mainly younger people, and they’re starting in the last two days to come forward to the trusts.”
Ms Donnelly has urged people to keep their appointments, or the vaccine and the opportunity to vaccinate someone else can be at risk of being wasted.
Earlier, Terry Maguire, from the Ulster Chemists’ Association, said up to half of people booked for their Covid-19 booster jab fail to attend the appointments on some days.
Northern Ireland’s chief scientific adviser, Professor Ian Young, said the vaccine gives around 80% protection against symptomatic Covid-19 six months after receiving both doses.
He said this protection increases to around 95% two weeks after receiving a booster jab,
“We don’t have the exact number for your reduced risk of hospitalisation but if anything it is going to be even greater than that,” he told the Nolan Show.