Bolton’s spike with 168 cases per 100 000 is being linked to one holidaymaker who did not isolate and who then went on a pub crawl with mates. Though anecdotal this is not implausible given the known highly contagious nature of Covid-19.
A similar incident was reported in Ayrshire in late August where one woman did not self-isolate and then attended several house parties in more than one town:
The difference between the two incidents seems likely to be the ability of local contact tracing teams to shut down the infection.
Again at the end of August, the Scottish First Minister reported that teams had traced 99.7% of positive cases.
Ayrshire had 20 cases per 100 000 in the last week down from around 40 in early September.
For comparison, between 30 July and 5 August, in England, only 79.7% were reached:
But only 53% were being contacted in heavily-infected North-West England where Bolton is located:
The spike around Glasgow is less than one-third of the size of the Bolton case per 100 000.