Despite the provincewide concern about the fast-spreading delta variant, York Region Public Health officials are projecting COVID-19 rates will continue to fall this summer, with no fourth wave on the horizon.
Based on vaccination rates and other trends, modelling data projects York Region would have approximately 880 cases between June 16 and Aug. 31, trending down to about eight daily cases by the end of August. The model also shows approximately 47 hospitalizations and 23 deaths in that time.
“I am surprised,” medical officer of health Dr. Karim Kurji said at regional council today, June 17, regarding the updated projections until the end of August. “The rapidity of the decline has surprised all of us. The only real difference is the fact we have vaccines, and the vaccine rollout has been so extensive.”
Regional Chairman and CEO Wayne Emmerson said vaccinations are progressing steadily, with approximately 74.8 per cent of eligible York Region residents age 12 and over at one dose, and 20.8 per cent at two doses.
Data scientist Linda Kaleis said they struggled to change values in the curve to create worst-case scenarios because vaccinations are progressing well. Even when increasing the effective contact rate to meet pandemic highs, the model only forecasted a “swell” of an extra 1,100 cases over the summer.
"If the current set of vaccine assumptions are maintained, we do not anticipate a fourth wave of cases among York Region residents, despite delta (variant) growth," she said.
The delta variant is a growing point of concern in the province and Kurji estimated about 40 per cent of cases in York Region are probably of that variant, though it is taking time to get exact totals laboratory-confirmed. Still, Kurji said the vaccines should protect enough residents against the delta variant.
“We are not unduly concerned about the growth of the delta variants in York Region as long as we continue with our vaccination efforts,” Kurji said.
The model assumes a 66 per cent first-dose efficacy against COVID-19. Kaleis said studies are showing positive results for vaccines preventing hospitalization from the delta variant. One United Kingdom study indicated one dose of Pfizer is 94 per cent effective, and Astra Zeneca is 72 per cent effective at stopping delta-variant hospitalization.
But data around catching the delta variant is more uncertain, and epidemiologist Shannon Meadows said they might have to adjust the model to 30 to 40 per cent efficacy for a first dose.
Kaleis showcased the regional modelling lacks the “worst-case scenario” from the Ontario Science Table, which shows a fourth wave could happen if the vaccine rollout slows. But Kaleis said York has a lower risk of that compared to the province as a whole.
“We actually have a very agile vaccine deployment,” Kaleis said.
The modelling until August. Newmarket Mayor John Taylor asked about the probability of a fourth wave in the fall, which Kurji said would also depend on vaccines.
“The more people that we have vaccinated, the less likely we are to see any waves,” Kurji said.
