Olympic tennis champion Belinda Bencic and Tunisian Ons Jabeur have tested positive for COVID-19 after competing in the Abu Dhabi exhibition, both confirmed on Tuesday, a day after Rafael Nadal announced he had also tested positive.
Former men's world number one Nadal's Spanish coach Carlos Moya, 45, also announced on Tuesday he had tested positive on his return from Abu Dhabi.
Jabeur replaced US Open champion Emma Raducanu after the Briton withdrew from the event after a positive test.
World number ten Jabeur said that despite being vaccinated she was "experiencing strong symptoms" and would be recuperating in her native Tunisia.
"I hope to overcome the virus quickly and get well soon," Jabeur added on Twitter.
"Unfortunately and even though I am fully vaccinated, I recently tested positive for COVID-19," 23rd-ranked Swiss Bencic also said on Twitter.
"I am currently isolating and taking all precautionary (measures) to get through this as best as possible as I am experiencing quite severe symptoms (fever, aches, chills).
"While the timing is not ideal - as I was in the final stages of my preparations for the Australian Open swing - I will make my way to Australia as soon as I am cleared and past the isolation period."
The Australian Open begins on January 17 in Melbourne.
Moya, winner of the French Open in 1998, said in a series of tweets he had been experiencing, "Fever, headache, sweating, pain all over the body, chills. I hope the worst is over."