Originally Published: 21 JUL 21 23:30 ET

Updated: 26 JUL 21 15:05 ET

By Seamus Fagan, David Close and Jill Martin, CNN

(CNN) -- The 2020 Summer Olympics are finally underway in Tokyo.

Competition began Wednesday, more than a year after the original start date after the Games were delayed due to the pandemic.

But with Covid-19 still spreading unchecked in Japan, organizers have been forced to take unprecedented steps to keep competitors and the public safe.

Athletes who contracted coronavirus have seen their Olympic dreams dashed. Some tested positive in Japan, some before coming.

These are the athletes we know who have publicly dropped out due to Covid-19 health and safety protocols.

Team USA: 6

Bradley Beal -- Men's basketball (Placed in health and safety protocol but hasn't publicly disclosed a positive Covid-19 test)

Taylor Crabb -- Men's beach volleyball

Kara Eaker -- Women's gymnastics

Coco Gauff -- Women's tennis

Katie Lou Samuelson -- Women's 3x3 basketball

Bryson DeChambeau - USA Golf

Team Czech Republic: 6

Barbora Hermannova -- Women's beach volleyball (Ruled out because her partner Sluková-Nausch tested positive for Covid.)

Simon Nausch -- Coach, women's beach volleyball

Ondrej Perusic -- Men's beach volleyball

Michal Schlegel -- Men's cycling

Pavel Širuček -- Men's table tennis

Markéta Sluková-Nausch -- Women's beach volleyball

Team Great Britain: 3

Dan Evans -- Men's tennis

Amber Hill -- Women's shooting

Johanna Konta -- Women's tennis

Team Mexico: 2

Hector Velazquez -- Baseball

Sammy Solis -- Baseball

Team Netherlands: 2

Finn Florijn -- Men's rowing

Candy Jacobs -- Women's skateboarding

Reshmie Oogink - Taekwondo

Team South Africa: 2

Kamohelo Mahlatsi -- Men's football

Thabiso Monyane -- Men's football

Team Australia: 1

Alex de Minaur -- Men's tennis

Team Chile: 1

Fernanda Aguirre -- Women's taekwondo

Team Portugal: 1

Frederico Morais -- Men's surfing

Team ROC (Russian Olympic Committee): 1

Ilya Borodin -- Men's Swimming