The Greek government on Thursday criticised tennis star Stefanos Tsitsipas for insisting he would only get a coronavirus vaccination if it became mandatory.
"He has neither the knowledge, nor the studies, nor the research work, that would allow him to form an opinion about it," government spokesman Giannis Economou said during a press briefing.
Economou said that while world number three Tsitsipas "is a great athlete, what is at stake, however, is his ability to assess the need for vaccinations or whether the vaccine has been tested for a sufficient period of time."
Tsitsipas is competing in Cincinnati this week where he revealed he has yet to take the vaccination.
"No-one has made it a mandatory thing to be vaccinated. At some point I will have to, I'm pretty sure about it, but so far it hasn't been mandatory to compete, so I haven't done it, no," he said.
"I'm young, under 25 category, for me the vaccine has not been tested enough, it is new. It has some side effects.
"I personally know some people who have had them. I'm not against it, I just see no reason for someone in my age group to need to be vaccinated."
He added that no one should be forced into taking the jab.
"I want to see a better version of the vaccine, which will give us more pluses than minuses," added the French Open runner-up.
However, Economou added Thursday: "I would say that those who, through their excellent presence and performance in other areas, are also a point of reference for wider social groups, should be doubly careful in expressing such views."
Meanwhile, in an interview with Greek public television ERT on Thursday, Tsitsipas's father and coach Apostolos backed his son's decision.
"Athletes have a strong enough immune system to deal with any challenge that may arise. They take the necessary measures, are in a controlled environment and do PCR and Antigen tests almost every day," he said.
