So the UK fast tracking first jab and delaying the second vaccination will backfire due to the new Delta variant.

Delta Variant and COVID-19 Vaccines: What to Know

In Northern Ireland, the gap between the first and second doses of the AstraZeneca and Pfizer vaccines is being cut to 8 weeks from 10-12 weeks to offer more protection against the delta variant, the BBC reported.

"It seems this variant can get past our first dose of vaccine," says Queen's University Belfast virologist Connor Bamford, according to the BBC. "So, we need to make sure as many people as possible get their two doses and even think about decreasing the length between dose one and two because that's going to be critical going forward."