#19,018
Although we are currently in an interpandemic period, mass gathering and travel events like Carnival in Rio, the Super Bowl, Mardi Gras, Chunyun (aka the Chinese New Year), the Summer & Winter Olympics, Umrah and the Hajj pose unique public health challenges not only for the host country, but for the world at large.
In each of these events - hundreds of thousands, sometimes millions - of people travel from all over the world to spend a few days or a week in a common, usually crowded, location where they can easily exchange viral and bacterial pathogens - mostly common, but occasionally exotic - before returning home.
Since many infectious diseases have relatively long incubation periods (7-10+ days), or may present mildly or even asymptomatically in some people, carriers - traveling both to and from the venue - may not be obvious.
This summer Toronto, Canada will host 6 FIFA World Cup matches in June and early July, with at least 300,000 visitors expected to descend on the city. In total, 16 cities across 3 countries (Canada, Mexico, U.S) will host the 2026 world cup, with over 5 million fans expected to travel to the various venues.
While this year's horrendous flu season will be hopefully ended by then, summer has often seen renewed surges in COVID transmission, Canada recently lost its measles elimination status, and food and waterborne illnesses are always a concern.
But there is a fairly long list of other - admittedly, less likely - infectious disease threats that must be considered.
While Canada won't be alone in having to plan for - and deal with - potential infectious disease outbreaks, yesterday Public Health Ontario published a 42-page Hazard Identification & Risk Assessment (HIRA) for the upcoming 2026 World Cup Games.
Purpose
Public Health Ontario (PHO) conducted a mass gathering (MG) HIRA to assess the potential likelihood and impact of infectious disease (ID) hazards while the City of Toronto hosts the Fédération Internationale de Football Association (FIFA) World Cup (FWC) 2026 games.
The tournament will be a global event, and these findings were used to inform public health planning priorities, preparedness and response measures for potential ID hazards. Relevant audiences for this product include the local and provincial public health agencies, public health practitioners involved in planning or response activities, as well as other jurisdictional and international health authorities interested in MG risk assessments.
Risk Question
For the identified ID hazard group, what is the likelihood of the event of interest occurring during May 28,2026, to August 2, 2026 (two weeks before and after the multi-site FWC tournament) and the impact to the public health capacity of Toronto and two neighbouring regions?
Scope
This assessment focused on ID hazards that may arise two weeks before, during, or two weeks after planned MGs as well as public health measures (PHMs) (i.e., non-pharmaceutical interventions to protect the health and well-being of communities)1 and surveillance that can be implemented before and in response to potential ID hazards. Risk to public health capacity was assessed; environmental, non-ID, and bioterrorism hazards were out of scope for this HIRA and will be addressed through other risk assessment work.
Key Findings
• Based on the assessment completed on September 2, 2025, the following IDs or ID categories were assessed as having a moderate risk level for the FWC 2026 games:
• Measles
• Food and waterborne diseases
• Coronavirus Disease 2019 (COVID-19)
• Food and waterborne illnesses are very common at MGs, as are respiratory illnesses, and have contributed to past public health investigations at Toronto MGs. Uncertainty around COVID-19 seasonality and circulating strains, and global measles activity and vaccination rates contribute to their potential for moderate risk at FWC 2026.
• All other IDs were rated at a low risk level considering outbreaks at past MGs, Ontario trends and existing preparedness, planning and response capacity. While other IDs were estimated as low risk, they still require planning and preparedness activities to mitigate potential exposures and impacts.
• Several planning considerations were recommended including:
• Pre-event assessment activities monitoring local and global epidemiology trends
• Planning for potential surge capacity for outbreak activities and public health investigations
• Considering the feasibility and utility of enhanced surveillance during the tournament
• Public health planning should consider pre-/during/post-event targeted risk communications and educational messaging for visitors and local populations (e.g., respiratory etiquette, up-to-date vaccinations, hygiene practices), as well as promoting awareness on anticipated illnesses, risk factors, and infection control and prevention (IPAC) guidelines among frontline healthcare workers (HCWs).
Some infectious disease hazards, like vector-borne and zoonotic diseases (VBZDs) may be of greater concern for venues in the United States or Mexico, than for Canada. And admittedly, the risks posed by MERS-CoV, avian flu, and Mpox could change between now and next summer.
Other health risks could be climate related, particularly in lower-latitude venues this summer, and this HIRA states that environmental, non-ID, and bioterrorism hazards are out of the scope of this report.
Presumably there will be public (and internal) reports from all of the other hosting cities in the weeks and months ahead. Of course, before we get to the FIFA World Cup, we've got 5 major mass gathering events in February; when subclade K is still expected to be going strong.
- the Super Bowl in Santa Clara, CA,
- the 2026 Winter Olympics in Milan Cortina, Italy
- Carnival in Rio de Janeiro, Brazil
- Mardi Gras in New Orleans
- and the biggest human migration of all; Lunar New Year aka Chunyun; The Spring Festival.
While we generally get through these events without a major outbreak, they undoubtedly contribute to the mixing and global spread of infectious diseases each year (see The Lancet: Proactive Surveillance for Avian Influenza H5N1 and Other Priority Pathogens at Mass Gathering Events).
Which is why public health agencies must remain on top of their game, even as the global sharing of valuable infectious disease information appears to be in steep decline.
