In the wake of the ongoing worldwide COVID-19 outbreak — which has now been declared a pandemic by the World Health Organization — the Public Health Agency of Canada (PHAC) has released new guidelines on how to decide whether it's necessary to cancel a mass gathering. 

1/5 .@WHO has determined that #COVID19 now constitutes a pandemic. The assessment by @WHO is not unexpected. In Canada, our public health system is prepared. #coronavirus

— Dr. Theresa Tam (@CPHO_Canada) March 11, 2020

Several major events including concerts, conferences and sporting events have already been cancelled across the country and worldwide, while other event organizers have decided to take their chances. 

The guidelines make it easier for those planning mass gatherings to make an informed decision when considering if an event should go forward in the midst of the COVID-19 outbreak. 

"Mass gatherings can contribute to the transmission of respiratory pathogens, such as the virus causing the current outbreaks of COVID-19. However, mass gatherings are not homogenous and the risk must be assessed on a case-by-case basis by Public Health Authorities, event organizers and relevant planners," the document states.

"Cancelling large events may be recommended from a public health perspective, but compliance and sustainability may be difficult and may cause significant social disruption and public resistance."

Cancelling mass gatherings. A difficult one to get right, as you don't want to cancel everything before anything happens, but on the other hand, you don't want to be Philadelphiahttps://t.co/8AHt4Tsq2A

— Allen Cheng (@peripatetical) March 8, 2020

PHAC instead recommends conducting a "risk assessment" in order to decide whether a mass gathering is worth calling off. 

They recommend assessing the crowd density of the event, how restricted points of access or exit are which may force participants through "high touch areas" (such as doors and elevators) and the accessibility of medical care on the premises. 

They also recommend evaluating the age diversity of spectators and participants since the virus is likely to hit older people harder, as well as whether it's an event where guests are likely to have recently travelled. 

The Government of Canada's "Risk-informed decision-making for mass gatherings during #COVID-19 global outbreak" page identifies dimensions for analyzing whether to cancel or postpone a mass gathering. https://t.co/s06jwkdGTj

— James Colliander (@colliand) March 11, 2020

"Limited environmental cleaning and the potential for individual health measures (e.g. hand hygiene) may play a role in increasing health risks at mass gatherings," the guidelines note. 

After completing the recommended "risk assessment," PHAC suggests making one of the following decisions based on the results: make no changes, enhance communication to attendees, employ risk mitigation strategies without cancelling the event, postpone the event or cancel it altogether. 

Examples of risk mitigation strategies include reducing the number of participants or changing the venue to prevent crowding, staggering arrivals and departures, providing packaged refreshments instead of a buffet, increasing access to handwashing stations and more. 

"Since mass gathering events, their settings, and participants/attendees are generally unique, the advice varies regarding which measures should be implemented," the guidelines note. 

"Public health authorities and event organizers must work together to assess the situation."