COVID-19 lockdown is needed: Vaccine won't be enough to save Ontario as variants rise 'very sharply', modelling suggests

Elisabetta Bianchini
·5 min read

New COVID-19 modelling data for Ontario paints a grim picture for future spread of the virus in the province, with a lockdown and more effective vaccine distribution needed to turn the tide with variants of concern.

Dr. Adalsteinn Brown, co-chair of the Ontario COVID-19 Science Advisory Table, began the presentation on Thursday by saying the information is "challenging."

"The third wave is here and being driven by variants of concern," the key findings from the modelling data states.

When asked if he is "frustrated" or "angry" with where Ontario stands, Dr. Brown said "No" but added that he is "hopeful that if the goal is to reduce the infection and the impact of this disease that the measures we take are strong enough to make sure that we can get the disease under control, we can protect our hospitals and we can get back to a normal life as quickly as possible."

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

COVID-19 cases of variants of concern, primarily the B.1.1.1.7. variant, first detected in the U.K. are growing "very sharply," Dr. Brown said.

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

Not only are these variants more transmissible, they have more severe consequences.

For every 10 patients that are expected to be hospitalized with COVID-19, that risk increases to 16 people if infected with a COVID-19 variant. For every 10 people admitted to the ICU, that expectation doubles for variant cases. For every 10 deaths from a non-variant case of COVID-19, 15 deaths are expected to be seen in variant cases.

"We have ongoing analysis right now that suggests that the risk of being put on a ventilator is now also three-times as high with the variants of concern," Dr. Brown added. "There is a much higher risk of asymptomatic transmission, up to 2.5 times greater risk of transmission before symptoms show."

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

The short-term projection for the province was developed assuming that vaccines have about a 70 per cent effectiveness, which Dr. Brown indicated is a slight underestimation compared to the Pfizer-BioNTech and Moderna vaccines. It also assumes that vaccines are being administered at a constant rate and randomly to the population. Dr. Brown said this likely leads to "a bit of an underestimation" of the growth of cases.

The projection shows that vaccinations alone won't curb the COVID-19 spread in Ontario, with a stay-at-home order required to bring cases down. The modelling shows that vaccines alone will result in 6,000 daily cases in the province by the end of April.

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

Hospitalizations and ICU admission have been a significant concern, particularly in recent weeks. There are 433 people with COVID-19 in Ontario ICUs. Dr. Brown stressed that unlike the time period between the first and second waves of COVID-19, this time ICUs were never emptied out before admissions spiked up.

When asked if a triaging protocol will be required in hospitals, the process of determining a priority of patients who are treated, Dr. Brown said that is up to the clinicians working in the IMS to manage but it is "a definite possibility."

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

Between Dec. 14 and Dec. 20, 2020, a time when there were significant concerns around the spread of COVID-19, there were about about 150 ICU admissions, with about one-third of them in people under the age of 60. 

Between March 15 and March 21, the number of ICU admissions was over 150 but there was also a substantial increase in the number of younger people being admitted to ICUs.

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

Dr. Brown identified that hospitalizations and ICU admission is a lagging indicator of cases and it does take longer to bring down, compared to bringing down cases alone.

"If we did show a longer projection, which is alway challenging looking out past a month or six weeks, you will see that the four-week [stay-at-home measure] empties out and reduces ICU occupancy much more significantly than the two-week stay at home," Dr. Brown said.

The modelling shows that Ontario will see 800 people in ICUs by around the third week of April, significantly exceeding that threshold without a stay-at-home measure added.

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

The latest modelling data also identifies that essential workers, communities with the highest number of essential workers, continues to be "bearing the brunt of the pandemic."

There is about a 51 per cent growth in infection with the variants of concern in these hardest-hit areas, opposed to about a 19 per cent growth in the areas where the lowest number of people are engaged in essential work.

"This is really important for thinking about how we make sure that we support people in these communities, we get vaccination and other initiatives into these communities to support control of the pandemic," Dr. Brown said.

Ontario COVID-19 Science Advisory Table
Ontario COVID-19 Science Advisory Table

While first dose coverage with COVID-19 vaccines is expanding, it's clear that older age groups are vaccinated more, while people in the most highest-risk communities are not being covered by the vaccine rollout at this point.

The information from the Ontario COVID-19 Science Advisory Table states that not reaching the communities with the highest COVID-19 risks with vaccines "delaying its impact as an effective strategy."