B.C. COVID-19 map: Here's where people have been testing positive during the Omicron wave

Where is the Omicron variant of COVID-19 being transmitted in B.C.? The short answer is everywhere, but data from the B.C. Centre for Disease Control's COVID-19 Surveillance Dashboard provides some insights into the hardest-hit areas. 

The local health area with the largest number of confirmed cases per 100,000 residents during the seven days from Dec. 31 to Jan. 6 was Revelstoke.

The Interior community saw 295 new infections per 100,000 residents during the time period in question, down from 332 per 100,000 the previous week.

The next-highest total for new infections per 100,000 was found in the Fernie local health area, which saw 208, up from 153 the week before.

These numbers reflect only COVID-19 cases confirmed through PCR testing or epidemiologically linked to confirmed cases.

B.C.'s testing system has been overwhelmed in recent weeks, and the province has been prioritizing lab-based tests for those ages 65 and older and people who have underlying conditions that put them at higher risk of serious complications from a COVID-19 infection.

People under that age without underlying conditions are offered rapid antigen tests if they seek testing, but provincial health officials have said fully vaccinated people who develop symptoms don't need a test. Instead, they should assume they have the disease and self-isolate for five days.

The largest raw number of COVID-19 cases confirmed through PCR testing from Dec. 31 to Jan. 6 was in Surrey. That's perhaps unsurprising given that Surrey is, by far, the largest local health area in the province, with a population more than 30 times that of Fernie and more than 55 times that of Revelstoke. Vancouver, which has a larger population than Surrey, is broken up into several local health areas.

With more than 3,000 newly confirmed cases during the week in question, Surrey accounted for about 15 per cent of the new infections in B.C. during the period.

On a per-capita basis, however, Surrey was not the hardest-hit part of the Fraser Health region. Surrey's rate of 91 lab-confirmed cases per 100,000 residents was lower than the rates seen in the Maple Ridge/Pitt Meadows (113) and Tri-Cities (129) local health areas.

While the vaccination rate in Maple Ridge/Pitt Meadows is slightly lower than the provincial average, both Surrey and the Tri-Cities have above-average rates of vaccination compared to B.C. as a whole.

Indeed, the Omicron variant's ability to infect people who have received two doses of vaccine has been a key driver of the pandemic's fifth wave.

According to the BCCDC dashboard, people who have received two shots have been testing positive for COVID-19 at a higher rate than those who are unvaccinated since Dec. 23.

There are a variety of potential explanations for this, including the aforementioned limits on PCR testing, which prioritize age groups that are more likely to have received two or three vaccine doses.

CTV News Vancouver reached out to the Ministry of Health for more information on what it sees as the most likely reasons that more vaccinated people are testing positive, per 100,000, than unvaccinated ones.

The ministry's response offered a four-part explanation for the situation. First, the protection against infection provided by the vaccine wanes over time. Second, Omicron is better at infecting vaccinated individuals.

"These two factors together lead to higher observed infection rates across many communities in B.C. relative to what we saw in the past," the ministry's statement read, in part.

Third, Omicron's prevalence "is not yet equally distributed" across the province, the ministry said, noting that it represents a smaller proportion of total caseloads in Northern Health and Interior Health. Those two regions happen to be home to some of the province's least vaccinated communities.

Finally, the ministry referenced testing.

"Cases have become a less reliable and meaningful indicator of population-level disease burden," the statement reads. "Testing practices and capacity have regional and local variations with many areas having reached capacity in recent weeks. In addition, the results of rapid tests are not systematically captured for provincial surveillance reporting purposes."

It remains clear that vaccinated people are far less likely to require hospitalization when infected with COVID-19, though it should be noted that BCCDC data does not separate hospitalizations caused by the Omicron variant from those caused by the Delta variant.

Between Dec. 7 and Jan. 3, unvaccinated people were admitted to hospitals for COVID-19 at a rate of 133.5 per 100,000, according to the BCCDC. People who had received two vaccine doses were hospitalized at a rate of 8.9 per 100,000.

Likewise, unvaccinated people were admitted to intensive care units at a rate of 47.9 per 100,000, compared to just 1.4 per 100,000 among those with two doses of vaccine.