UNVACCINATED people are Covid "variant factories" who could prolong the pandemic and lead to more restrictions, scientists have warned.
The dire prediction comes as the World Health Organisation warned that mutant strains are already outpacing the current wave of jabs as much of the world had hoped the virus horror could be coming to an end.
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More than half of the world's population have not yet had a dose of the Covid vaccine - with some three billion doses administered worldwide.
And while the highest jab rates in the world are figures such as 73 per cent in Iceland and 67 per cent in the UK, some of poorer nations such as African countries have barely scratched the surface.
The world is still seeing some 2.7million cases of the virus every week - with hundreds of thousands of infections in Brazil and India.
It is feared gaping holes in the global vaccine coverage combined with rampant outbreaks will allow new variants - such as Delta and the newly concerning Lambda strains - to spawn.
Mutations may then be able to beat vaccines and potentially force countries back into lockdown as they face being taken back to square one in the fight against Covid.
And it also comes as many nations see continuing anti-vax sentiment as many people refuse to get the jab.
Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center, told : "Unvaccinated people are potential variant factories.
"The more unvaccinated people there are, the more opportunities for the virus to multiply.
"When it does, it mutates, and it could throw off a variant mutation that is even more serious down the road."
The UK delayed lockdown lift in June was down to the Delta variant as medics wanted to monitor the new strain's spread - and while July 19 remains nailed on, it has been warned Britain could face a hard winter.
Andrew Pekosz, a microbiologist and immunologist at the Johns Hopkins Bloomberg School of Public Health said: ""As mutations come up in viruses, the ones that persist are the ones that make it easier for the virus to spread in the population.
"Every time the viruses changes, that gives the virus a different platform to add more mutations. Now we have viruses that spread more efficiently."
The current generation of vaccines at the moment offers good protection against the latest wave of variants, but fears loom all the time a new mutation could spring up and sidestep the jabs.
"All it takes is one mutation in one person," said Dr. Philip Landrigan, a pediatrician and immunologist at Boston College.
WHO issued a warning this week as they continued to urge more vaccine sharing - describing the current donations from rich to poor nations as a "trickle".
Dr Tedros Adhanom Ghebreyesus, WHO's director general, described the world as being "outpaced by variants" - pointing out the Delta mutation is now in 98 countries.
The top doc said world leaders must ensure 10 per cent of people in every country should be vaccinated by the end of September.
Previously, The People's Vaccine Alliance (PVA) - a global coalition of 50 organizations - told The Sun Online about the critical danger the new strains pose if more support isn't given to help vaccinate people worldwide.
"This failure puts us all at risk," Anna Marriott, health policy manager at Oxfam, said.
New mutations on the coronavirus can make it harder for the body's immune system, which has been primed to look out for the "original" strain either through vaccination or prior infection, to recognise it.
Antibodies - proteins produced by the immune system to fight the virus - may be weaker against new strains.
The threat of new coronavirus strains also means masks and social distancing could be needed for years to come, despite the vaccine rollout, and it is not clear when border controls will be relaxed.
And its feared should a new variant take hold, further lockdowns may needed to clamp down and stop the spread and save lives.
Menwhile, six scientists, doctors and experts last month penned a dire warning in an essay for titled "The Forever Virus" as they warned Covid is "not going away" and herd immunity is "unreachable".
"Such supervariants could bring the world back to square one. It might be 2020 all over again," the scientists warned.
They added: "The virus is here to stay. The question is, What do we"
Almost 4million people have so far been killed by the virus which first emerged in China back in December 2019.
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UK health secretary Sajid Javid has argued the Britain is going to have to "learn to live with Covid" - and compared its future to that of the flu.
He has has vowed to lift the remaining coronavirus restrictions on July 19 as he plans to make Britain the "most open country in Europe".
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Mr Javid also urged everyone to get their jab as soon as they are offered one, describing the vaccination programme as "the single biggest contribution you can make to this national effort".
And meanwhile ministers are considering whether to allow fully vaccinated people to carry on life as normal — with no quarantine or daily tests — if they come into contact with someone with coronavirus.