Recent seven-day case rates have risen rapidly for Cornwall and the Isles of Scilly, increasing from 4.9 per 100,000 people on 3 June to 130.6 per 100,000 people on 16 June.
Outbreaks among students, as well as the impact of people travelling to and from Cornwall during half term, are believed to have significantly contributed to the rise.
There have been significant outbreaks in Carbis Bay – where the G7 summit was held – as well as nearby St Ives, and Newquay West – where many delegates stayed.
Rates are currently high in Ponsanooth, Mabe Burnthouse and Constantine, where the surge has been linked to an outbreak at the Penryn campus shared by Exeter and Falmouth universities.
Andrew George, the former Lib Dem MP for St Ives who is now a councillor in Cornwall, said the government must publish its risk assessment for the summit, a request he said had been denied.
“The correlation between G7 and the tsunami of Covid-19 caseload in St Ives/Carbis Bay and Falmouth is undeniable,” he told the Press Association.