BC not providing enough information on Omicron and BA.2 sublineage, says modelling group

A new report from an independent group that models the COVID-19 pandemic in BC says it’s hard to know where we are in the Omicron wave, due to incomplete information.

“In terms of where we are in the pandemic—it’s very hard to tell. And that’s partly because of the changing and incomplete datasets that we have access to and that the province has access to,” Dr Sarah Otto, who’s a member of the BC COVID-19 Modelling Group, told the Beacon.

“With testing rates declining among most people, we can’t use the case numbers. … It’s hard to know how much of the current hospital trends can reflect changing policies versus actual changes in the numbers.”

BC changed its testing guidelines in late December, in the weeks after Omicron became established in BC. And it’s only become harder to get a test since then. Provincial health officer Dr Bonnie Henry has said anyone with symptoms consistent with COVID should assume they’re infected.

New guidelines from the BCCDC updated Feb 4, meanwhile, say testing should be conducted in a similar manner as other diseases: only a positive or negative test will inform decisions about treatment and care.

But while those testing guidelines may preserve PCR and rapid tests for those who are at highest risk of severe illness, Otto said it also makes it difficult to know how the pandemic is progressing in BC.

Henry told reporters last month that it appeared Omicron cases had reached their peak in early-mid January. Otto isn’t as confident.

“I’m confident that the reported case numbers peaked in January. I’m also very confident that infections almost certainly did not. Because of the fact that the number of cases in people over 70 should have gone down at that point, and the number of hospitalizations should have been going down long ago,” she said.

“I said within our group, ‘Well, I’m pretty sure that the peak was either in the past, in the present or in the future,’ and I got laughed around the room. But I think that’s the level of uncertainty that we’re facing right now.”

There is what Otto calls “major good news” in terms of hospitalizations. While hospital admissions are far higher now than they have been at any other point in the pandemic, they are still well below the possible worst case scenarios that the modelling group considered.

She said we need to pay close attention to hospital admissions as BC moves to end more restrictions in the coming weeks.

The modelling group has been watching reported cases in people above 70 carefully, because testing has been more accessible to them so far this wave than other age groups. Otto said that means they may be able to provide a “good enough” snapshot of what’s happening to infection rates.

The good news on that front, she said, is that cases aren’t rising in that age group—but the bad news is that they’re not falling either. Instead, they’ve plateaued at a very high case rate.

There’s a number of possible explanations for that plateau. One, Otto said, is that the effect of booster doses could be waning in that age group, which was the first to receive its third doses. Another could be that this is the peak of case rates in people over 70, and that the decline could begin shortly.

But another possibility is that BA.2, a sublineage of the Omicron variant, has also begun circulating—and declining case rates of BA.1 (also known as B.1.1.529, which has so far made up the majority of Omicron cases) have been masked by increasing case rates of BA.2.

The trouble is, it’s impossible to know, because BC has shared very little information about the prevalence of BA.2 here. The BCCDC’s latest weekly report on variants of concern, published Feb 4, makes no mention of the sublineage at all.

In late January, Dr Bonnie Henry told reporters there had been a “small number” of BA.2 cases confirmed in the province—as Global News reported, the exact number was 66 at that time.

The BC COVID-19 Modelling Group, meanwhile, points out that BC has submitted only 11 BA.2 samples to GISAID—an international initiative that promotes the sharing of influenza and COVID-related data—to date, “making it impossible to assess if BA.2 is spreading.”

“In particular, I am concerned about the spread of BA.2 in other jurisdictions, and preliminary data from Canada and from BC is suggesting that it may be spreading at similar rates. And so how is that contributing to the pandemic? Well, I can’t tell because the data isn’t shared in a public fashion,” Otto said.

“And all of that uncertainty means—I think not just from us on the outside, but also on the inside—it’s just challenging right now to know where we are and what the future will bring.”

Otto is not as optimistic as some that Omicron may be the last COVID wave, “lift[ing] us out of the pandemic”.

“We heard that before Omicron!” she laughed, referencing similar hopes when the Delta wave hit.

“What I can say is that the next variant is facing a much higher level of immunity across the population.”

But if that variant is significantly different enough from Omicron or other previous variants that it can “sneak around” the neutralizing antibodies that prevent us from getting infected, it could be a wave we need to watch out for.

“So are we in this game of wave after wave after wave? I actually am very hopeful about new scientific innovations that are looking at vaccinating more broadly—not for one variant at a time, that’s kind of like playing whack-a-mole,” Otto said.