Stroll was confirmed to have coronavirus after the Eifel GP, where he did not race because he was unwell, but he was not tested at the event.
Team principal Otmar Szafnauer said: “If I thought our process was wrong, I would change it.
“I’m not going to do anything else. There is nothing else to do.”
Szafnauer’s explanations of Stroll’s symptoms have been inconsistent.
At the Nurburgring event two weeks ago, he said Stroll had first felt unwell with an upset stomach at the preceding race in Russia and in Germany he could not race because he had “flu-like symptoms and [was] just not well in himself and couldn’t exercise, together with a tummy bug”.
Fever, fatigue and diarrhoea are three of the possible symptoms of Covid-19 listed on the websites of the World Health Organisation and the US government’s Centre for Disease Control.
But when challenged in a news conference on Thursday as to why the team did not consider Covid-19 was a possibility, Szafnauer said: “I’m not sure he had flu-like symptoms. He had a stomach upset.”
When it was pointed out to him that he had said Stroll did have flu-like symptoms, Szafnauer said: “Well, if I did, I misspoke. He had a stomach upset and he’s had it consistently. Lance called his doctor. I’m not a physician.”
It also emerged the doctor Stroll consulted was not on site in Germany but was the family private doctor in Switzerland, and that they spoke by telephone.
F1 has strict protocols to minimise the risks of coronavirus, but Szafnauer revealed he had tried to persuade Stroll to take part in the race weekend when the driver said he wanted to withdraw on the morning of qualifying.
“The doctor told him the symptoms aren’t Covid symptoms, he didn’t feel up to coming into the paddock,” Szafnauer said. “I tried to get him to run on Saturday and to race. I said, ‘Come on, upset stomach, you had it in Russia. Come and race.’ And he said: ‘I don’t feel up to it.'”
Stroll flew home to Switzerland on the morning of the race without being tested, but took a test when he arrived back. This returned a positive result.
“Hindsight is a wonderful thing,” Szafnauer said. “But he tested twice post-Russia negative. The symptoms were there post-Russia. But at the time, with the information we had, it was unnecessary. It didn’t even come into my mind, go and do a test. Even the test on Sunday was scheduled long, long ago.”
Szafnauer defended the team’s Covid procedures, insisting they “test more than any other business on the planet”, and saying all employees are tested twice a week, and anyone travelling to races is tested in addition on their return to the UK.
Teams are obliged to report any positive cases after an event to governing body the FIA, but Racing Point failed to do this until they announced news of Stroll’s test on Wednesday this week – more than a week after the result.
The FIA, which has the power to bar competitors from events for breaches of its Covid code, has issued them a reminder of their responsibilities, but will take no further action.
Stroll, who revealed his positive test on Wednesday, said he had tested negative in a further test at the beginning of this week and would be racing at this weekend’s Portuguese Grand Prix.
Racing Point have Nico Hulkenberg, who replaced Stroll at the Nurburgring, on stand-by at the Algarve track in Portugal in case of any problems.
Stroll’s father Lawrence, who owns the team, has also contracted coronavirus.
The Canadian billionaire tested negative on the Thursday of the Eifel Grand Prix, when he was at the Aston Martin factory in the UK, but took a further test at the same time as his son in Switzerland on Sunday, 11 October. This came back positive.
The team say Lawrence Stroll, who is 61, is symptom-free.
Lance Stroll is the second Racing Point driver to contract coronavirus this year after Sergio Perez missed the two Silverstone races in the summer when he tested positive after a trip to Mexico to see his mother.
No other team has had a driver test positive, although a number have had positive cases among staff.