COVID-19 hospitalization data is being misunderstood as next wave begins: BC modelling group

The BC COVID-19 modelling group’s latest report highlights a mistake in the way people are interpreting the province’s COVID-19 hospitalization data, which appears to incorrectly indicate hospitalizations are declining.

The group of experts points out that the BCCDC weekly reports are incomplete and do not show the actual number of COVID-19 hospitalizations in the past week.

When the corrected numbers are released one week later, the modelling group found that they always show about a 25% higher number of hospitalizations than the original.

The group’s report showed one example of this incorrect data being used by a Victoria newspaper last month to state that COVID-19 hospitalizations are declining, when in fact, corrected data showed hospitalizations had plateaued and were starting to rise at that point.

“They want to read that report and they want to say, ‘Are the trends going up? Are the trends going down?’ and you cannot read the weekly report by itself that way,” Dr. Sarah Otto, UBC professor, infectious disease modelling expert, and modelling group member told Capital Daily. “You have to compare it to the same information a week behind in the previous weekly report.”

In BC, as in Europe and the US, Otto and the modelling group’s report say COVID-19 hospitalization rates could already be trending upwards again.

Source: BC COVID-19 Modelling Group

With most people having antibodies against the virus at this point in the pandemic—either from prior infection or vaccination—the experts’ opinions align with public health officials: this next phase of the pandemic will be driven by waning immunity levels.

“Many of us were infected in January, February, March, April, and now that protection is waning, and…every day that it wanes is another person in BC that the virus can infect,” Otto said. “Add on top of that, we know that there's variants—currently at low frequency in Canada—that can better evade our immunity and it's not a great situation. It kind of suggests that we're in for a double whammy.”

The province is encouraging people to sign up to get their booster shots once they are invited six months after their last vaccine, in a step towards rebuilding people’s resistance to the virus. However some, like Victoria physician Dr. Amy Tan’s 13-year-old son, have not been able to get a booster shot even after getting to the six month mark.

BC is expecting a major spike in COVID-19 and respiratory illness-related hospitalizations this fall. According to projections they presented last month, the province can expect up to 700 COVID-19 hospital admissions at a time starting mid-November—the current number is around 350 people in hospital—and up to 1,200 admissions caused by influenza.

“We could really tamp down this wave if a lot of people were getting vaccinated, but we're not seeing really high uptake of vaccines, as far as I know,” Otto said. “We're basically getting as many people vaccinated as [are] getting infected every day right now in BC.”

In BC, the number of people getting infected each day far exceeds what is being reported by the province. The modelling group estimates, based on Canadian Blood Services data, that the actual number of daily infections is 100 times higher than official reports, which puts actual case counts at about 10,000 per day.

The BCCDC’s own pre-print study, co-authored by Dr. Bonnie Henry, looked at blood samples from the Lower Mainland and found cases are underreported by 92 times.

Playing Russian Roulette

There are far too many uncertainties to be able to predict what this fall will look like for hospitalizations, reinfections, and long COVID, according to Otto, but one thing people should expect is the likelihood of getting infected three or four times before the year ends. This is especially likely if some of Omicron’s sub-variants— ones that are more likely to evade antibodies and have already emerged in Canada—start spreading more widely.

For many, COVID-19 is not a debilitating illness, but Otto argues there are several reasons to get a booster shot when it is available.

“First of all you’re less likely to get sick,” she said. “And if you don’t get sick, you don’t risk long COVID, you don’t risk going to hospitals, and you also prevent all of the people that you would have exposed from getting infected.”

The impact of vaccines and repeated reinfections on the likelihood of contracting long COVID is still uncertain.

One study published in Nature Medicine earlier this year, involving data from over 13 million people from the US Department of Veterans Affairs database, found vaccines seemed to reduce the likelihood of developing post-COVID symptoms by only 15%. A more recent but smaller study in Israel, involving 3,572 participants, found that people who had gotten two doses of vaccine were between 50 and 66% less likely to develop long COVID symptoms like fatigue, headache, weakness in limbs, and muscle pain.

A US pre-print study involving over five million people that was published in June found that the risk of long COVID increases with reinfections. Studies are still ongoing to determine how COVID-19 reinfections interact with other factors, like age and vaccination status, in causing post-COVID symptoms.

“At present, it is like playing Russian Roulette,” Otto said. “I have had friends and colleagues who have spent months unable to work because of long COVID. That's not something that anybody wants.”