TORONTO -- The number of cases of COVID-19 in Canada has surpassed the number of cases related to the SARS outbreak in 2003, a sobering milestone that health officials have been warning about from the beginning.

When SARS hit Canada roughly 17 years ago, by the end of the outbreak there had been 438 probable and confirmed cases of the virus, most contained within Toronto and the GTA.

As of Tuesday night, Canada has 598 confirmed or presumptive cases of COVID-19 across not merely one or two provinces, but across all ten provinces. No cases have been reported yet within the three territories.

Within Ontario alone, there are nearly 200 cases.

COVID-19 and SARS both come from the same family of coronaviruses and have similar symptoms. What makes COVID-19 more dangerous than SARS is a number of factors.

"For COVID-19, [transmissibility] is at a two or three. That means one person can give the virus to two or three other people," explained Dr. Chen Liang, an associate professor with McGill University's department of medicine. He said SARS transmissibility was much lower.

In the beginning of the COVID-19 outbreak, much was made of the fact that SARS had a higher rate of fatality, at 10 per cent.

But COVID-19’s higher transmissibility means that if a significantly higher number of people can catch it, the overall death count in Canada could overtake the death count related to SARS.

In 2003, the SARS outbreak — largely focused in Ontario, although one case was identified in Vancouver — caused 44 deaths.

So far, COVID-19 has killed five people in Canada, but as cases show no sign of slowing down, the number is expected to rise.

Worldwide, the difference is vast between the two viruses. COVID-19 has killed over 7,800 people, while SARS caused over 900 deaths.

Health officials say the world should have been better prepared.

Johan Neyts, professor of virology and president of the Belgian-based, International Society for Antiviral Research (ISAR), told AFP that the world missed a chance after SARS.

"If we had invested starting in 2003 at the SARS epidemic looking for a medication that would be active against coronas by now we could have had a stockpile that would have been active against this new one," he told AFP.