Health experts have stressed that getting two doses of Covid-19 vaccines is crucial in the fight against the rising Delta variant.
There is growing concern about the rapid spread of the Delta variant, formerly known as the Indian variant, with British prime minister Boris Johnson on Monday announcing a four-week delay in lifting restrictions across the UK.
Dr Connor Bamford, a virologist at Queens University Belfast, said there is unease about the spread of Delta.
In Northern Ireland, the Public Health Agency has identified 111 probable and confirmed cases of the Delta variant up to June 9 across the region.
“It does appear to be different, and it does appear to be worse and by worse we mean that it seems to spread better,” he said.
As the number of cases starts to increase across the UK generally, modelling experts are looking at the potential impact on hospitals in two to three weeks.
“When we put those into models, it can lead to a large surge, a significant surge in the coming months,” he said.
Dr Bamford said while public health measures including waste-water surveillance, rapid testing and whole-genome sequencing are all working better than in 2020, vaccines are crucial.
“The vaccinations are our way out at the moment, it is a little bit of a race between vaccinating people with two doses before the virus catches up with us,” he said.
As the threat increases, the Northern Ireland Department of Health has “reduced the interval between doses from 10 weeks to six weeks” for new vaccine appointments scheduled from Monday onwards.
In the Republic, tracking of the Delta variant, and another variant first identified in India called Kappa, shows 262 confirmed cases, up from 218 a week ago.
Cliona O’ Farrelly, professor of comparative immunology at Trinity College Dublin, said people should "remain vigilant.”
She said as long as Covid-19 is spreading in any country, there is a chance of even more variants developing.
“Antibodies may be lower against Delta but hopefully cytotoxic T-cells provide protection,” she said.
“One way or the other, people should make sure they get both jabs.”
New data from Scotland shows Delta is now the dominant variant there.
Vaccines were found to reduce the risk of being admitted to hospital, but strong protective effects were not seen until at least 28 days after the first vaccine dose.
Dr Jim McMenamin, Covid-19 national incident director for Public Health Scotland, said: “These results provide early encouragement that two doses of either Pfizer or AstraZeneca vaccines significantly reduce the risk of infection against both the Alpha or new Delta variants.”
“Though no vaccine can be 100% protective, they provide the best protection against Covid-19 and it remains important to get both doses when offered.”