The 30-year-old, currently sixth in the 2020 standings after three races, then had a re-test which came out positive, meaning he will unsurprisingly miss the British GP this weekend - which still plans to go ahead.
A Racing Point statement read: "Sergio is physically well and in good spirits, but he will continue to self-isolate under the guidelines of the relevant public health authorities, with safety the ultimate priority for the team and the sport.
The entire team wishes Sergio well and looks forward to welcoming him back into the cockpit of the RP20 soon. Our intention is to race two cars on Sunday. We will communicate the next steps for our British Grand Prix weekend in due course.
In a statement, the FIA said a "full track and trace initiative" has been undertaken, while the "swift containment" means the case will not impact the weekend's racing at Silverstone.
"Following today’s announcement that Sergio Perez of the BWT Racing Point Formula 1 Team produced an inconclusive test result for COVID-19 at the Silverstone Circuit ahead of the 2020 FIA Formula 1 British Grand Prix, the FIA and Formula 1 can now confirm that the result of his re-test is positive.
"Perez has entered self-quarantine in accordance with the instructions of the relevant public health authorities, and will continue to follow the procedure mandated by those authorities.
Canadian-Belgian formula one driver Lance Stroll (L) and Mexican formula one driver Sergio Perez (R) of team BWT Racing Point F1 during a press presentation in Mondsee, Austria on February 17, 2020
Image credit: Getty Images
"With assistance of the local organiser of the British Grand Prix, local health authorities and the FIA COVID-19 delegate, a full track and trace initiative has been undertaken and all close contacts have been quarantined.
"The procedures set out by the FIA and Formula 1 have provided for swift containment of an incident that will have no wider impact on this weekend’s event."
Perez not at Silverstone on Thursday
A spokesman for the Silverstone-based Racing Point team said Perez, who was not at the circuit, had not been back to Mexico since he last raced in Hungary on July 19.
F1 drivers and team personnel are only allowed in the paddock once they have returned a negative test, with the sport's testing regime now having returned three positive results so far - Perez is believed to be the first driver.
Perez currently sits sixth in the F1 drivers' championship, having finished sixth, sixth and seventh in his three races so far.
After two races in Austria and one in Hungary, the next two engagements for the F1 calendar are both at Silverstone.