Ontario is likely entering a new wave of the pandemic accompanied by the more contagious BA.5 variant, according to the province's scientific advisory team.

This was announced in a series of messages posted on Twitter this Wednesday afternoon, citing the "exponential growth" in cases in about 80 percent of public health units as well as rising hospitalization numbers and positivity test rates.

On the other hand, scientists also said that wastewater signals in most areas are now rising, indicating generally higher levels of viral activity.

 The advisory team said that "current evidence does not indicate that BA.5 is more severe or that it will lead to a rise in hospitalizations like previous waves; however, any increase comes at a time when hospitals are already dealing with staff shortages and recording wait times – and this affects us all.

Adding, "And if BA.5 spreads widely, we may see an increase in deaths among higher-risk groups such as the elderly as observed during previous waves."

The warning from the scientific advisory team comes at a time when several countries are witnessing a rapid rise in transmission due to the BA.5 variant.

In Ontario, where the variant now predominates, most public health indicators have also started trending the opposite way after months of gradual improvement.

The latest data from the Ministry of Health on June 30 showed a weekly increase in COVID-19 hospitalizations for the first time since May.

The positivity rate in PCR tests also rose, with the seven-day average increasing from 7.64 on June 23 to 9.82 on June 30.

Meanwhile, public health measures that were in place during previous waves of the pandemic have now ended, including the mask mandate for high-risk settings which was lifted last month.

There is no evidence that BA.5 is more severe

 The scientific advisory team said that "there is no evidence that BA.5 is more severe or that it will lead to a rise in hospitalizations like previous waves."

But it added: "We may see an increase in deaths among higher-risk groups such as the elderly as observed during previous waves."

 This is a global phenomenon

On the other hand, Ontario's Chief Medical Officer of Health, Dr. Kieran Moore, told local media this is a global phenomenon, with no plans to reinstate mask mandates or other public health measures. "With our borders open, with travel returning, it is natural for this virus to spread worldwide."

Explaining, "But Ontario is doing well so far in minimizing its impact on the healthcare system."

On the other hand, the scientific advisory team says that Ontario residents should take a number of precautions due to the high transmission rate, including "returning to wearing masks again in crowded indoor public places, and ventilating indoor spaces as much as possible by opening windows and doors.

Moore also said that Ontario residents should make sure to keep up with their vaccinations.

Adding, we are reviewing (the fourth dose) eligibility for further expansion in the coming days with government approval, but my message today is that if you have not had a booster dose, please come forward to us."

"If you are eligible and 60 years or older, and five months have passed (after the third dose), your protection against severe outcomes decreases month after month."