Olympics host city Tokyo, as well as Thailand and Malaysia, announced a record number of Covid-19 infections Saturday - mostly driven by the Delta variant.
Cases numbers increased in Sydney as well, where police cordoned off the central business district to prevent a protest against a lockdown that will last until the end of August.
Earlier in the weekend the U.S. Centers for Disease Control and Prevention declared in an internal report Delta spreads much faster, is more likely to infect the vaccinated and could potentially trigger more severe illness in the unvaccinated compared with all other strains. It said Delta was now dominant across the world.
In Australia, police closed train stations, banned taxis from dropping passengers off downtown and deployed 1,000 officers to set up checkpoints and to disperse groups. The government of New South Wales reported 210 new infections in Sydney and surrounding areas - all from the Delta variant.
Tokyo's metropolitan government announced a record number of 4,058 infections in the past 24 hours, topping 4,000 for the first time. Olympics organizers reported 21 new Covid-19 cases related to the Games, bringing cases to 241 since July 1.
Japan extended its state of emergency for Tokyo to the end of August, expanding it to three prefectures near Tokyo and the western prefecture of Osaka in light of the recent spike in infections.
Olympics organizers said Saturday they had revoked accreditation of a Games-related person or people for leaving the athletes' village for sightseeing, a violation of measures imposed to hold the Olympics safely amid the pandemic.
The organizers did not disclose how many people had their accreditation revoked, if the person or people involved were athletes, or when the violation took place.
The Delta variant is as infectious as chickenpox, and the centers said governments must "acknowledge the war has changed" given how dangerous the variant is.
However, other scientists said the likelihood of vaccinated people spreading the virus, if infected, was much rarer compared with unvaccinated people.
Delta is more transmissible than other viruses in the coronavirus family such as Mers and Sars, as well as Ebola and smallpox, the centers said in its report but added that although vaccines prevent more than 90% of severe disease, the dangerous characteristics of this variant suggested they may be relatively less effective at preventing infection or transmission.
"I think people need to understand that we're not crying wolf here. This is serious," centers director Rochelle Walensky told CNN. "It's one of the most transmissible viruses we know about. Measles, chickenpox, this - they're all up there."
Data shared in the presentation suggested that vaccinated people who become infected with the Delta variant can shed just as much of the virus as unvaccinated people, although it emphasized that vaccines prevent more than 90% of severe disease.
Meanwhile, in Malaysia, one of the hot spots of the disease, reported 17,786 coronavirus cases Saturday, a record number of infections.
More than 100 people gathered in the center of the capital Kuala Lumpur, expressing dissatisfaction with the government's handling of the pandemic and calling on Prime Minister Muhyiddin Yassin to quit.
Protesters carried black flags and held up placards that read "Kerajaan Gagal" (failed government) - a hashtag that has been popular on social media for months.
Thailand reported a daily record of 18,912 new coronavirus infections, bringing the country's total accumulated cases to 597,287. The country also reported 178 new deaths, also a daily record, taking total fatalities to 4,857.
The government said the Delta variant accounted for more than 60% of the cases in the country and 80% of the cases in Bangkok.
The Delta variant is not necessarily more lethal than other variants, but much more transmissible, Supakit Sirilak, the director-general of the Medical Science Department, told Reuters.
China is also battling an outbreak of the Delta variant in the eastern city of Nanjing, traced to airport cleaners who worked on a flight from Russia.
Covid-19 infections have increased by 80% over the past four weeks in most regions of the world, World Health Organization director-general Tedros Adhanom Ghebreyesus said Friday.
"Hard-won gains are in jeopardy or being lost, and health systems in many countries are being overwhelmed," Tedros told a news conference.
