The rising number of COVID-19 cases fueled by the Omicron variant has experts worried that new strains will continue to emerge if the global population doesn't get vaccinated.

Experts told CNBC it is only a matter of time before a new variant appears due to the lack of vaccines available in poor countries.

“Until the whole world is vaccinated, not just rich Western countries, I think we are going to remain in danger of new variants coming along, and some of those could be more virulent than Omicron,” said Dr. Andrew Freedman, an academic in infectious diseases at Cardiff University Medical School.

Although the variants “tend to become milder” as they mutate, Freedman revealed there is no guarantee that the next strain will be less severe.

“It may well be with future variants that they are even more contagious, they may be milder, but we can’t say that with certainty," he said.

Danny Altmann, professor of immunology at Imperial College London, previously told CNBC that ending the COVID-19 variants would depend on richer countries donating their extra vaccines to the COVAX initiative.

The international program alleviates the economic and public health impact of the pandemic by ensuring global equitable access to vaccines.

“This isn’t altruism or aid or anything, this is the global escape strategy from something that we’re all suffering together,” Altmann explained.

“Unless we can share out the vaccines and produce enough vaccines for everybody, the next variant is just around the corner.”

The warning comes as the Biden administration reportedly plans to make a shift to prepare Americans to accept COVID-19 as a part of life after previously declaring the nation was “closer than ever to declaring our independence from a deadly virus” in July.

The administration has since suggested many Americans will become infected with the virus but vaccinated people shouldn’t be too concerned.

“You can control how big an impact Omicron is going to have on your health,” Biden has said. “We’re seeing COVID-19 cases among [the] vaccinated in workplaces across America, including here at the White House. But if you’re vaccinated and boosted, you are highly protected.”

Over the weekend, White House Chief Medical Advisor Dr. Anthony Fauci warned that the spike in cases of the Omicron variant could overwhelm hospitals across the nation.

A health worker prepares the Pfizer-BioNtech Covid-19 vaccine in the city of Joinville, Santa Catarina, Brazil
A health worker prepares the Pfizer-BioNtech Covid-19 vaccine in the city of Joinville, Santa Catarina, Brazil AFP / Carlos JUNIOR