Like much of north-west England, Bolton saw a rise in coronavirus cases in October, a lull over Christmas, and then another wave in January.
By mid-April, lockdown had forced daily infections back almost to single figures locally. Then something worrying happened.
Rates started rising sharply again – doubling in the last week of April, then doubling again in the first week of May.
“We’ve got higher rates in the younger age groups, but the increases are now happening across all the under 60s,” says Lynn Donkin, the assistant director of public health in Bolton.
“That suggests to me that we’ve got transmission within households and that’s now part of the situation here.”
Samples from Bolton were sent to scientists at Public Health England who identified a variant of the virus – now known as B.1.617.2 – that was first spotted in India earlier this year.
“Initially we did see some cases linked to international travel,” says Ms Donkin.