The recent rise in COVID-19 cases and hospitalizations in Ontario that has led to the sixth wave is linked to the Ford government’s decision to lift mask mandates in most public settings, the province’s public health agency suggested in a new brief.

“Close monitoring of epidemiological trends since March 21, 2022 (the date of mask mandates removal) suggests a corresponding temporal association with a subsequent increase in confirmed COVID-19 cases and hospitalizations,” the report published Friday by Public Health Ontario (PHO) read.

The agency noted that the full impact of lifting the mandate might not be observable due to limited PCR testing and lagging hospitalization data.

Ontario is currently in the midst of its sixth pandemic wave, which PHO said is being driven by the more transmissible BA.2 Omicron sub-variant. The agency noted that evidence suggests high viral load may play a role in increased transmissibility of the sub-variant

“Confirmed case counts and the test positivity rates are increasing and currently higher than during the pandemic to date and indicative of Ontario being on the upswing of a sixth pandemic wave,” PHO said.

Earlier this week, Dr. Peter Juni, the head of the Ontario Science Table, said wastewater data show that the province is seeing between 100,000 and 120,000 new cases each day.

Ontario has seen a 40 per cent week-over-week increase in hospitalizations. On Saturday, Ontario reported 1,188 people in hospital with COVID-19.

In the brief, PHO also reported that the province could see an increase in COVID-19 infections among children. The agency said it could impact pediatric hospital and intensive care capacity and lead to further interruption to in-person learning.

“With expected increased infections among children associated with increased transmissibility of BA.2, removal of public health measures, and limited vaccine eligibility and two-dose coverage in children less than 12 years, the number of children with severe disease is likely to increase,” the report read.

Reintroducing universal indoor masking in schools and other public settings and extending masking in high-risk settings could be effective at reducing transmission, PHO said.

There have been calls to reinstate mask mandates, especially in schools, as absences among students and teachers continue to climb. Public health experts have criticized the province for ending the mandates, saying it was a mistake.

“Prevention strategies layered onto a vaccination strategy can mitigate a surge in the current context of a more transmissible dominant variant and when case rates are higher than during much of the pandemic to date,” PHO said.

“Optimizing layers of prevention in K-12 schools, including temporary re-implementation of masking requirements indoors and improved air quality can reduce the risk of in-school transmission and related disruption for students, families and educational settings.”

PHO said public health officials should stress the importance of wearing masks to the public to blunt the sixth wave.

“Risk communication to the population regarding high levels of SARS-CoV-2 transmission and COVID-19 disease risk may also be helpful, including in the context of collective actions such as community masking,” the report read.

However, Ontario Health Minister Christine Elliott, citing Chief Medical Officer of Health Dr. Kieran Moore, said earlier this week there is no need to reinstate mask mandates as the rise in cases was expected.

PHO warned that there is growing evidence that a new COVID-19 variant of concern could emerge and “drastically change the course of the pandemic.”

“The emergence of the BA.2 sub-lineage when jurisdictions were experiencing the decline of the BA.1 and BA.1.1 waves underscores the need for high quality surveillance, building on past experience related to removal of public health interventions, vaccination, and preparedness for the next stages of the COVID-19 pandemic.”