Serology survey suggests B.C. far from avoiding potential second COVID-19 wave

VICTORIA (NEWS 1130) – B.C. is far from stopping a second wave of COVID-19 if we’re to base it on a recent serology study, the BC Centre for Disease Control says.

The study, conducted by the BCCDC, UBC, and LifeLabs, concludes that less than one per cent of the population in B.C. has had COVID-19.

“We do not have sufficient immunity in the population to prevent subsequent waves, and it may not even just be a single second wave. We may be looking at undulations,” the BCCDC’s Dr. Danuta Skowronski, the epidemiology lead of Influenza & Emerging Respiratory Pathogens at the BCCDC, says.

It found a COVID-19 prevalence rate of 0.28 per cent in March and 0.55 in May. If applied to the whole population of B.C., the prevalence rate would put B.C.’s case count at closer to 28,000 than the 3,149 confirmed by officials so far.

Despite the higher number, the results tell Skowronski one thing for sure: our immunity levels provincially aren’t where they need to be.

“That’s very clear from these findings. We have a long way to go before we’re there, which means it really comes down to the individual and collective measures of British Columbians to continue to keep this virus at bay.”

Dr Danuta Skowronski says the protocols used here were established in 2009 during H1N1. Gives quick snapshot of infection rate in the community, can continue to do snapshots to guage changes in risk as the virus continues.#bcpoli @news1130

— LizaYuzda (@LizaYuzda) July 16, 2020

Skowronski says we need to remain vigilant.

“We cannot rest on our laurels. We cannot assume that we’re in the all-clear, because it also means that there is still substantial residual susceptibility in the population,” Skowronski notes.

The study looked at samples in Metro Vancouver, where researchers expected the infection numbers to be the greatest. Samples of were taken from hundreds of people who were providing samples for other reasons — a point researchers say was to ensure a truly random collection.

Skowronski adds an infection rate of less than one per cent means British Columbians have been doing a very good job in slowing the spread of COVID-19, noting B.C.’s numbers are among the best in North America.

Provincial Health Officer Dr. Bonnie Henry says British Columbians can be proud of their efforts.

“We did what we needed to do,” she says. “It basically reinforces that what we did, the timing was good, and that they were effective measures.”

However, she also reiterates B.C.’s low infection rates mean we’re far from immunity that could stave off another wave.

Study doesn't show if antibodies protect from future infections or how long this might last.
Does show clearly BC doesn't have near enough protection for herd immunity. It will require the restrictions/protections we've been using to keep it at bay.#bcpoli @news1130 #covid19

— LizaYuzda (@LizaYuzda) July 16, 2020

Henry says the study doesn’t show if antibodies present in the samples will protect against future infections, or how long potential protection could last.

“This also helps us understand that broad-based testing using serology in B.C. is likely not going to be very helpful for us in the near term,” she explains. “So we’re going to be looking at, for example, the people who answered our survey — about 300,000 people answered this survey, close to 400,000, actually — that we did looking at the impact of the pandemic and the measures that we put in place.”

Of those people, Henry notes, half have signed up to be part of serology studies.

“What we need to do is target those groups that will give us more information about who has potentially been at increased risk. For example, healthcare workers or people who work in certain areas that had been working during the pandemic, for example. So those are things that we’re now using, the findings of this, to help us moving forward.”