Social distancing and mask-wearing are here to stay as new COVID-19 variants will continue to emerge and be "troublesome", according to an expert.
David Nabarro, a special envoy on coronavirus for the World Health Organisation, said more strains are "inevitable".
It comes as India said on Tuesday that the new Delta plus variant recently discovered in the country is of concern and that nearly two dozen cases had been detected in three states.
Speaking to Sky News, Dr Nabarro said the "issue of variants is what we are watching all over the world" and they "are going to go on coming".
"We will go from Delta to Lambda and then on to the other Greek letters, that's inevitable, and some of these variants will be troublesome," he said.
"They will be able to break through the vaccine-related protection in a few people and that will cause problems."
He added: "I'm basically saying variants are going to go on coming. That's part of life, we need to pick them up fast, we need to move quickly if we see them in a certain location, we need to build the management of variants into what we call our COVID-ready strategy, which is going to be the pattern for the foreseeable future."
Due to new strains, Mr Nabarro suggested that mask-wearing and keeping apart would still be necessary for areas of high infection.
He said there was a need to "maintain defences against the virus to stop it welling up more and more, and that's going to be the life to come, at least until there's enough vaccine, and enough certainty, to be sure that vaccination will protect us. Right now we can't say that."
Dr Nabarro said we will have to continue social distancing as well as using vaccines "as part of our defence" against COVID-19, particularly in virus hotspots.
He suggested that workplaces should also continue to keep social distancing measures in mind.
"There will be a need for every single workplace to be asking, 'is it right that we stop wearing masks and stop maintaining distance?" he said.
"Because that's the way you prevent people from getting infected and that's the key to stopping big spikes building up... I am advocating continued physical distancing, continued mask wearing for the time being, including in countries where there's a lot of vaccination."
Dr Nabarro also said people should only be travelling abroad for "absolutely essential" reasons, adding that "it's not yet the time for unrestricted travel to start".