He has called for countries "to be a little more patient".
Dr Mike Ryan of the World Health Organisation (WHO) has issued a warning to countries about the "premature rush" to return to normality, saying the spread of the Delta variant has the potential to cause "huge trouble".
On Monday, the UK announced an easing of restrictions which includes the removal of laws governing social distancing and face coverings, and an end to official advice to work from home.
This is despite cases, driven by the Delta variant, hitting a seven-day average of 25,447 in the UK this week.
Speaking during a Q&A on Facebook with epidemiologist Dr Maria Van Kerkhove, Dr Ryan said some countries have made "a very premature rush back to full normality".
"I think we are going to pay a price for that, because we are not there at vaccination, the variants are really there and we have not protected enough people," he added.
He said that for many around the world, the pandemic is simply beginning and not ending, as the world is not where it needs to be in terms of vaccinations.
“All of the countries of the Americas, we still have nearly one million cases a week. It isn’t over," he said.
"It's the same in Europe, we have half a million case a week. It’s not like this thing has gone away."
He called on countries to have a little more patience and pointed to last summer, where he said everyone relaxed and cases spiralled in September and October.
Ryan added there's the potential to end up in "huge trouble" with the much more transmissible Delta variant.
