Health experts fear the Tokyo Olympics could become a COVID-19 superspreader event.

The big picture: Infectious disease experts say the Olympics don't have strong enough protocols for testing or ventilation, either in competition venues or in the Olympic village.

"What kind of ventilation systems do they have? The last check-in we had with them, in their Olympic Village apartments, there wasn't the kind of adequate ventilation that would substantially reduce the spread of the virus," said Michael Osterholm, an infectious disease expert at the University of Minnesota.

• Osterholm and a group of other researchers published safety recommendations for the Olympics earlier this year, but with the opening ceremonies fast approaching, they say they've seen little measurable progress.

Testing is a core component of the International Olympic Committee's playbook, but it'll be too easy for cases to slip through the cracks and then spread, said Annie Sparrow, a professor at the Icahn School of Medicine at Mount Sinai Hospital.

• While there are daily testing protocols for the Olympic teams, the workforce has a varying frequency of testing depending on their role.

"What about the workers, the volunteers, the bus drivers exposed for 14 to 16 hours a day who are going into the village and then going back home to their families?" said Sparrow, who helped advise the WNBA through the pandemic.

Details: The IOC's playbook calls for attendees to physically distance themselves from others, to wear masks, and to get tested daily. They are also required to use a location-enabled contact tracing app on their smartphones.

• An IOC spokesperson said 85% of the delegations will be vaccinated, as well close to 100% of IOC staff.

Yes, but: Japan has a meager 19% vaccination rate, and recently extended its state of emergency due to rising COVID cases and the Delta variant.

• The experts also said the IOC fails to distinguish the risks posed in different competitions, such as contact sports or those that occur indoors, in its final playbook.
• Some of the IOC's suggestions — like suggesting that athletes open their windows every 30 minutes — aren't supported by science, Osterholm said.
• And while formal guidelines call for social distancing, Sparrow pointed to media reports that show some facilities, namely a cafeteria, set up for what looks like full capacity.
• The IOC did not respond to specific criticisms regarding their COVID safety protocols.

What's next: In the two to four weeks it would take for a COVID-19 surge to be detected as the result of the Olympics, a new collection of international delegations will arrive for the Paralympics.

• “My mind boggles when I think about, 'What are the risks here?'" said Lisa Brosseau, a bioaerosol scientist and research consultant.

Context: Other sports organizations have navigated this successfully, but experts said the IOC's precautions simply aren't as strong as those employed last year by the NFL or the NBA.

• "I think [the NFL] understood the concept of airborne transmission and what it meant and they planned accordingly," said Osterholm, who helped advise the NFL's safety precautions.

The bottom line: "We all want the Olympics to happen. The world needs good news right now," Osterholm said. "But we want it to happen as safely as possible."