Saliva tests versus throat swabs. Delta versus omicron. The “bubble” versus the “closed loop.”

The Tokyo and Beijing Olympics have taken radically different approaches to holding the world’s biggest international sporting events during a global pandemic, influenced by ever-changing collective knowledge on COVID-19 and how to prevent its transmission.

But despite the trials and tribulations that affected both events, they eventually reached the starting gates — and on Sunday, barring any extraordinary developments, Beijing is expected to meet Tokyo at the finish line.