Ontario's COVID-19 Science Advisory Table has released new modelling, predicting a grim fourth wave that accelerates rapidly in the fall and almost entirely affects the unvaccinated.
The modelling was released after 5 p.m. Wednesday without the usual notice to media and the accompanying government press conference.
The far more infectious Delta variant is already putting increased pressure on hospitals, largely due to unvaccinated people becoming infected and severely ill, the table said. The vaccines provide excellent protection against severe outcomes.
The predictions show a wide range of possibilities.
Assuming an increase in contacts due to people being inside more as the weather gets colder, new daily cases could reach 9,000 by Oct. 1. If contacts decrease due to new public health measures, case numbers could remain stable or decrease slightly.
The scientists called for a decrease to 70 per cent of pre-pandemic contact levels, through reducing indoor capacity, mask policies, working from home and limiting large gatherings.
Without a reduction in transmission, there could be more people in intensive care by October than there were at the peak of the third wave, the table found. Many people had delayed surgeries and other medical procedures due to hospital occupancy concerns.
"Substantial progress" will also be needed on vaccines, the report says. Just 66.9 per cent of all Ontarians are fully vaccinated; including 76.4 per cent of the eligible population 12 and up, for whom the vaccines are approved. That number needs to hit 85 per cent and above to blunt the fourth wave, the table said.
It called for more policies that accelerate vaccination, such as certificates, mandates and outreach.