Castigated for refusing to be vaccinated against COVID-19 because he said it wouldn't affect the young, Greek tennis star Stefanos Tsitsipas has changed his mind and said he will take the shots.

He earlier said he would do so only if the Association of Tennis Professionals (ATP) made it mandatory but his stance at the same time Greece was trying to persuade people the vaccinations are safe and effective saw him ripped at home.

Ranked third in the world, he said he was worried about side effects that doctors and scientists have said are far less worse than getting the Coronavirus that kills.

His change of heart was reported by Antenna TV which noted that the ATP has urged players to be inoculated but the world number one, Novak Djokovic – who had contracted the virus – said he's opposed to the shots nonetheless.

"I will get vaccinated this year," the 23-year-old said. "So I can go to restaurants and shops. I support all those who get vaccinated.” That was in reference to Greece's New Democracy barring the unvaccinated from indoor spots.

"I am not a doctor; I am a tennis player, so I may not have the most substantiated opinion when it comes to medical issues,” he admitted.

"The COVID-19 vaccine has not been tested enough because it is new and has some side effects," Tsitsipas had said although world health bodies and scientists working at record rates developed shots that have beaten back the pandemic, but slowly because of anti-vaxxers who think the vaccines aren't safe or effective or part of an international conspiracy to alter their DNA and control their minds.

"I know some people who've had them. I'm not against it, I just see no reason for someone in my age group to be vaccinated,” he had said earlier.

Tsitsipas is set to play for Team Europe at the Laver Cup in Boston after missing Greece's Davis Cup tie with Lithuania due to a foot injury keeping him out.