Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

A participant celebrates the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

A participant celebrates the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Participants celebrate the Sydney Gay and Lesbian Mardi Gras Parade under coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott TPX IMAGES OF THE DAY

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

An attendee celebrates the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

Attendees celebrate the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

An attendee celebrates the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

People in costumes arrive ahead of the Sydney Gay and Lesbian Mardi Gras Parade under the coronavirus disease (COVID-19) safety guidelines at the Sydney Cricket Ground in Sydney, Australia, March 6, 2021. REUTERS/Loren Elliott

A healthcare professional administers a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the programme, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic talks to the media as fans are seen with Serbia's flags during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Craig Tiley, CEO of Tennis Australia talks to the media during a photo shoot as a runner is seen at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with a fan during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 The Australian Open champion Serbia's Novak Djokovic autograph is seen on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Staff during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy and a fan during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Craig Tiley, CEO of Tennis Australia talks to the media during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott TPX IMAGES OF THE DAY

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

A healthcare professional administers a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

A healthcare professional administers a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional prepares a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional prepares a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional prepares a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

High-risk worker Dr. Chris Quinn reacts after receiving the Pfizer coronavirus disease (COVID-19) vaccine in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional prepares doses of the Pfizer coronavirus disease (COVID-19) vaccine as part of the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional administers a dose of the Pfizer coronavirus disease (COVID-19) vaccine to Dr Chris Quinn as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

A healthcare professional administers a dose of the Pfizer coronavirus disease (COVID-19) vaccine as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A healthcare professional prepares a dose of the Pfizer coronavirus disease (COVID-19) vaccine for Dr Chris Quinn as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

A sign for a COVID-19 vaccination clinic is seen as high-risk workers receive the first vaccines in the state of Victoria's rollout of the program, in Melbourne, Australia, February 22, 2021. REUTERS/Sandra Sanders

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott