Russell's F1 trainer self-isolating after showing COVID-19 symptoms

Williams F1 driver Russell's trainer, Aleix Casanovas, self-isolated on Thursday and will undergo a test on Friday outside of the paddock that must return negative before he can enter the circuit.

Russell and Casanovas have not been in contact since race day for the Portuguese Grand Prix last Sunday, since when both have returned negative test results for COVID-19.

Russell is set to undergo another COVID-19 test on Friday, and was last tested on Tuesday as part of the new entry requirements for Italy, returning a negative result.

"After displaying mild respiratory symptoms this morning, Williams can confirm that George Russell's performance coach is self-isolating today in line with FIA guidelines," a spokesperson from Williams told Autosport.

"A COVID-19 test collected yesterday was negative, however he will undergo a further precautionary test again tomorrow outside the paddock before taking further directions from the FIA.

"He has not been in contact with George since race day in Portugal.

"George undertook his scheduled COVID-19 test on Tuesday in order to enter Italy today - which was also confirmed as negative.

"He will be retested at the track on Friday as part of the team's regular testing schedule."

Williams' designated reserve driver, Jack Aitken, will be on-site at Imola from Friday, and has previously attended a number of grands prix this season in support of the team.

All personnel attending grands prix this season are required to undergo regular screening for COVID-19, taking a test every five days at events, as well as one within 24 hours of arriving at the venue.

As per the FIA's COVID-19 protocols, "an attendee who begins to suffer from any COVID‐19 symptoms while outside the venue must report immediately to the nearest medical facility" with guidance from their team.

The COVID-19 Code of Conduct in the FIA's International Sporting Code lists symptoms as "fever, cough, shortness of breath, fatigue, headache, runny nose (rhinitis), sore throat (pharyngitis), loss of sense of taste or smell, a skin rash, and/or discolouration of fingers or toes (and/or such other symptoms as the World Health Organisation may specify from time to time)."

The WHO states that COVID-19's incubation period - the time between exposure to the virus and symptom onset - is an average of five or six days, but can be as long as two weeks.