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September 13, 2021 Analysis of BC regional data

This page shows results of analyses reported in our regular BC COVID-19 Modelling Group reports.

Fits to each health authority case data

The public health measures brought into force for the Interior Health Authority in late July have successfuly stopped the growth in daily cases. The growth rates in all regions have also reduced significantly, although daily cases in the Northern HA continue to grow at about 5% per day.

The following shows graphs of daily cases on linear and log scale.

The dashed curves illustrate how cases from the variants overtook the cases from the original strains, and note the hypothesized introduction of delta at a low level and low rate of growth, consistent with what was known at that time.

BC total












Comparison of case rates for the health authorities

The transition to rapid growth and the changes since are shown in the plot below.


The table below indicates the growth rates (shown as percent per day) for each region for recent analyses. The trend to reduced growth rates is evident. Typical uncertainty (68% CL) is about 1%/day, but for recent estimates, the uncertainties are larger, so are included in the table.

Region July 28 Aug 3 Aug 10 Aug 16 Aug 24 Aug 30 Sep 7 Sep 13
BC +9% +9% +9% +8% +3% +2% +1% +/- 1% +1% +/- 1%
Fraser +8% +7% +8% +7% +7% +3% +2% +/- 1% +2% +/- 1%
Interior +12% +11% +8% +6% +1% 0% -1% +/- 1% -1% +/- 1%
Coastal +6% +6% +7% +7% +6% +2% -2% +/- 3% -1% +/- 2%
Island - +7% +9% +9% +7% +4% -3% +/- 4% +1% +/- 3%
Northern - +14% +15% +14% +10% +5% +5% +/- 3% +5% +/- 2%

The plot below compares the daily cases as a proportion of HA population. The Northern HA has a large and growing case prevalence. It is too early to see the effect of additional health measures enacted for NHA in early September.


Hospitalization projections

The figure below shows unfitted projections for hospital and ICU occupancy, assuming the growth in case rates from the figure above. It can be seen in the graphs that growth in hospital occupancy will be delayed compared to the growth in cases. The rise in hospitalization due to the recent growth of delta is apparent, although the ICU occupancy is somewhat higher that the projection.

The plots are shown in linear and log-scale.



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