B.C. researchers struggle to predict next COVID wave with minimal data

Is it allergies, or do you have COVID-19? Reinfection with the virus is becoming more common, according the latest public health data from some provinces, but some say B.C. isn’t offering up enough information to help predict what the next wave will look like.

Saskatchewan’s chief medical health officer, Dr. Saqib Shahab, says getting COVID-19 twice was once considered unusual but then the Omicron variant arrived. Shahab says because the virus is so different than other strains, a previous infection doesn’t protect you. He says public health data suggest up to 10 per cent of infected Canadians who have recently had BA.2, a sub-variant of Omicron, previously had BA.1 or Delta.

While provinces like Ontario and Quebec are reporting thousands of COVID reinfections, B.C. has not been publicly releasing that information, and scientists say it makes it challenging to predict when and how bad the sixth wave will be.

In its latest report, the independent BC COVID-19 Modelling Group says it believes B.C. is at the beginning of a second Omicron wave. Dr. Elisha Are, a member of the group as a Postdoctoral Fellow in Mathematics at Simon Fraser University, says they are able to look at some factors to tell BA.2 is spreading faster than the previous variant, similar to the spread of Alpha.

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Many have questioned how public health officials can say ‘cases are rising’ with limited testing. Are says they can see some data which support those statements, including ongoing sewage testing, and hospital numbers. He also says those 70 and older have still seen some consistently high testing levels, despite other age groups dropping off, and they use that age group as a kind of barometer for their research.

However, he echoes calls from the other modellers who want real-time data, including reinfection rates, released from the province.

“Without these multiple data sources, a model cannot, you know, cook up how much cases we’ll see,” he said.

With more data, he says it would be easier to gauge the threat level of BA.2 compared to other waves. He says it would create “a model that can say that given this level of immunity in the population, given this level of previous exposure, given this level of vaccination, then we can expect this level of resurgence in cases.”

“There’s always a room for improvement everywhere in the world. Scientists everywhere in the world always have challenges with data because we need them in real time. But policymakers have other considerations too as to data collection,” Are said, adding “of course, modellers will be happier to have access to more data, because that’s basically what feeds our model and our projections.”

He says a lot of researchers are using global data to draw their conclusions – and a lot of scientists are focusing on two countries in particular. South Africa has seen a much more modest BA.2 wave, while the United Kingdom is seeing similar levels of hospitalization as in the BA.1 wave.

“So that kind of gives us two contrasting scenarios that we can see and [say] ‘okay, what is similar in the UK and B.C. and what kind of outcome?’… Are we going to go the South African way or somewhere in between? So and I think the difference my opinion will be the level of immunity in the population.”

He says B.C. “with the high level of vaccination coverage, and access to boosters, especially those in vulnerable situations” will likely fall in the middle but admits it’s difficult to say with certainty.