COVID-19 case maps: Neighbourhood-level data adds nuance to B.C.'s infection information
VANCOUVER -- What a difference a month makes.
Between April 4 and 10, the B.C. Centre for Disease Control's weekly map of COVID-19 cases in Metro Vancouver was awash in dark red, signifying the highest rate of transmission shown on the map.
During that week, all but two cities in Metro Vancouver saw more than 20 new coronavirus cases per 100,000 residents each day.
Flash forward to the latest map, which shows infections diagnosed between May 2 and 8, and the dark red regions are fewer.
East Vancouver, Surrey and Delta are the only regions in Metro Vancouver with more than 20 cases per 100,000 residents per day on the latest map.
Just outside Metro Vancouver, Abbotsford and Mission are also over the 20-cases-per-100,000-residents threshold. The only other local health area in the province to cross that line during the week that ended May 8 was Golden, B.C., near the Alberta border.
The BCCDC released its newest map of coronavirus cases by local health area on the same day it released its first public map of cases by "community health service area" - a smaller unit that allows neighbourhood-level comparisons in large cities.
Journalists and members of the public had been asking B.C. health officials for neighbourhood-level data for months, but the province has only just started to release it, after internal data was leaked to Postmedia last week.
Combining the data from the community health service area maps with that shown on the local health area maps yields some notable insights.
The neighbourhood-level map released Wednesday shows cases recorded between May 4 and 10, meaning it's not directly comparable to the local health area map, which covers a slightly different timeframe.
Still, the overlap between the two maps is significant enough that the trends seen on one are reflected in the other.
For example, while the City of Delta, as a whole, recorded more than 20 cases per 100,000 residents between May 2 and 8, most parts of the city saw a much lower per-capita case count between May 4 and 10.
Northeast Delta, along the city's border with Surrey, recorded between 20 and 40 cases per 100,000 residents per day, according to the neighbourhood-level map, while the rest of the city saw five or fewer cases per day, the lowest per-capita total seen in Metro Vancouver.
Likewise, there are notable variations within Surrey itself. The city's central and northwestern neighbourhoods saw more than 40 daily infections per 100,000 residents between May 4 and 10 and test-positivity rates north of 20 per cent in some areas.
Other parts of the city, particularly South Surrey and Cloverdale, had lower daily cases counts and positivity rates.
While the local health area map still shows more than 20 cases per 100,000 residents for the City of Surrey as a whole, the city's overall numbers are beginning to trend in the right direction.
The local health area that encompasses most of Surrey saw 1,409 new coronavirus cases from May 2 to 8. That's still, by far, the largest total of any local health area in the province.
However, it's a significant decrease from the previous week, when the region saw 1,671 new infections detected.