WASHINGTON - In a press briefing Friday, the head of the WHO said the delta variant is "quickly becoming the dominant strain in many countries," and thus, the world is in a "very dangerous period" of the COVID-19 pandemic.
"Delta is spreading in at least 98 countries and is spreading quickly in countries with low and high vaccination coverage," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said.
According to WHO, cases are doubling every three weeks in Africa — with more than 20,000 new cases reported Friday in South Africa.
Meanwhile, Public Health England says cases of the delta variant have increased fourfold in the U.K. in less than a month, accounting for 95% of confirmed cases of the coronavirus.
Italian health officials are also warning the delta variant has been steadily gaining traction in the country since May.
In the U.S., the variant makes up at least 20% of reported COVID-19 cases and is expected to become the dominant strain in the country, according to health officials. In Missouri, the state is seeing an alarming rise in cases because of a combination of the fast-spreading delta variant and resistance among many people to getting vaccinated.
"I have urged leaders across the world to work together to ensure that by this time next year 70 percent of all people in every country are vaccinated," Tedros said. "This is the best way to slow the pandemic, save lives, drive a truly global economic recovery and along the way prevent further dangerous variants from getting the upper hand."
He added that 3 billion doses of COVID-19 vaccines have already been distributed and "it’s within the collective power of a few countries to step up and ensure that vaccines are shared."
"By the end of this September, we are calling on leaders to vaccinate at least 10 percent of people in all countries. This would protect health workers and those at most risk," Tedros continued.
Scientists believe the delta variant is about 50% more transmissible than other coronavirus strains and there are early clues that mutations may ease a key step in how the virus slips inside human cells, said Priyamvada Acharya, a structural biologist at the Duke Human Vaccine Institute.
On Thursday, the White House said it plans to deploy "surge response" teams to help combat potential outbreaks amid rising concerns over the delta variant, as well as work to get more shots in arms in areas where vaccination rates are low.
"As both Dr. Walensky and Dr. Fauci just made clear, the delta variant is a threat to unvaccinated Americans and to communities with low vaccination rates. And the best way for communities to protect themselves from the virus is by getting more people vaccinated," White House coronavirus coordinator Jeff Zients said.
The delta variant got its name from the World Health Organization, which names notable variants after letters of the Greek alphabet.
Viruses constantly mutate, and most changes aren't concerning. But there is a worry that some variants might evolve enough to be more contagious, cause more severe illness or evade the protection that vaccines provide.
Recent studies have shown that the available vaccines work against variants, including the delta variant.
Researchers in England studied how effective the two-dose AstraZeneca and Pfizer-BioNTech vaccines were against it, compared with the alpha variant that was first detected in the U.K. The vaccines were protective for those who got both doses but were less so among those who got one dose.
In a separate study, Moderna said this week that an analysis of blood samples from people who had received the company’s vaccine showed a strong level of antibodies indicative of robust protection against known variants.
This story was reported from Los Angeles. Catherine Park and Kelly Hayes contributed.