When the World Shows Up at Your Door

This summer, football comes to North America, and it’s bringing its friends. From the fan zones of Miami to the plazas of Mexico City and the streets of Toronto, millions of supporters will descend on a continent that calls the sport soccer and is about to find out what the rest of the world already knows: that the Fédération Internationale de Football Association (FIFA) World Cup is less a sporting event than a temporary reorganization of human geography.

The 2026 edition (running June 11 through July 19 across the US, Mexico, and Canada) is historic in scale: 48 nations, 104 matches, 39 days, and 11 US host cities stretching from Boston to Los Angeles and Seattle to Miami.¹ It is anticipated that between 3 and 5 million domestic and international visitors will descend on these cities,² some arriving from countries with meaningfully different infectious disease landscapes than the cities hosting them.

For infection preventionists (IPs), hospital epidemiologists, and public health practitioners working in or near any of these host cities, this is not a background event. This is a clinical and operational reality that, if we’re being honest, is probably already giving you a bit of heartburn.

It is a Tuesday in July 2026. A man from Guadalajara, Mexico, flies into Dallas, spends 4 days eating street food at a fan zone, sits shoulder to shoulder with 90,000 people in a stadium, boards a train to Los Angeles, watches 2 more matches, and then flies home. His seatmate on that last leg will be a woman from São Paulo, Brazil, who hasn’t slept properly in a week. She will connect through Miami. Her cousin, who is picking her up from the airport, will be immunocompromised.

Pathogens are the ultimate stowaways. They don’t see walls or international borders; they simply see new neighbors and a free ride. They thrive in high-density areas and close proximity, moving effortlessly from one warm body to the next. When the tournament ends and it’s time to head home, those fans return to your jurisdiction and hospital emergency departments, ready to become the topic of your very next call to public health.

Three Countries, 1 Very Complicated Party

Every World Cup carries infectious disease risk. Mass gatherings are, by design, optimal transmission events: thousands of people with different vaccination histories, varied health statuses, and recent travel from countries with endemic pathogens that local systems have never had reason to develop clinical instincts for. Add warm summer days, alcohol, shared food, and fluid crowds, and you have ideal conditions for germs to travel.

What makes 2026 structurally different from every previous edition is the trinational architecture. Qatar 2022 was geographically compact—a country roughly the size of Connecticut, 1 health infrastructure, and central coordination. Russia 2018 was geographically expansive, spanning 2 continents and 11 cities. It relied on rigid, federally mandated health architecture with a heavy emphasis on standardized emergency readiness. This tournament spans 3 countries with 3 separate health systems, 16 host cities, and a fanbase that will move fluidly between them.²

The CDC captured the cascading implications in its March 2026 interim guidance for state, tribal, local, and territorial health officials: Every jurisdiction, whether hosting an official FIFA event or not, should be approaching this from a risk-based lens.³ Because fans travel between venues. Because the championship final at MetLife Stadium in New Jersey draws people from every corner of the globe. Because those people fly home from Newark through Atlanta, through Chicago, through Phoenix, and through your local airport. The geographic complexity of this tournament is not a logistics problem for FIFA. It is an epidemiological problem for everyone downstream.

Transmission risk isn’t confined to the stadiums. In Philadelphia, the official FIFA Fan Festival at Lemon Hill will coincide with the massive America250 celebrations on July 4. These events draw huge, fluid crowds where heat, alcohol, and all-day festivities create the perfect environment for a virus to move. Beyond these official hubs, thousands of informal watch parties will gather in homes and bars, extending the tournament’s transmission arc far beyond any stadium seat.

The Pathogen Passenger List

Let’s talk about pathogens, because those are, ultimately, what we’re here for.

Respiratory infections are perennial frontrunners at mass gathering events, and 2026 will be no exception. For the World Cup, the respiratory risk landscape includes COVID-19, influenza, and measles,² with the last disease particularly concerning given rising rates in both the US⁴ and Canada⁵ and elevated incidence in several participating nations. Tuberculosis (TB) rounds out the respiratory risk profile; it is highly transmissible in close quarters and endemic at elevated rates in many of the nations represented in the tournament.²

Foodborne and waterborne illnesses are where the data get interesting. A retrospective review of stool samples from the 2022 FIFA World Cup in Qatar identified foodborne pathogens in nearly 20% of samples. Among positive bacterial isolates, Salmonella led at 40%; norovirus dominated the viral category at 35%.⁶ Layer in summer heat, mass catering, shared food and drinks, and the nearly inevitable hand hygiene gaps of a fan zone, and you have nearly perfect conditions for fecal-oral transmission.^2,7

Sexually transmitted infections (STIs) tend to spike at major international events, and several host cities have already flagged this as a specific concern. HIV, gonorrhea, chlamydia, mpox, and syphilis are all on the radar. Public health messaging around condom availability and STI testing access will be critical, as will ensuring that rapid STI testing panels are available at facilities likely to see international visitors.²

Vector-borne disease introduces what is one of the more underappreciated dimensions of this tournament. A visitor from Central America may arrive in a US host city already infected with dengue, whereas visitors from South America might arrive incubating yellow fever.⁷ What makes the World Cup context unusual is the bidirectionality. That same visitor from Central America may return home with Lyme disease acquired in the northeastern US, a diagnosis their home country’s clinicians have essentially no experience with, because it doesn’t exist there. The World Cup is, among other things, a large-scale natural experiment in pathogen redistribution, and the direction of travel goes both ways.

Finally, there are the high-consequence pathogens: those where the probability is low, but the margin for error is zero. Viral hemorrhagic fevers (Ebola, Marburg, and Lassa fever) and anthrax belong in this category.^2,3,7 What makes them operationally distinct is not just clinical severity but the speed at which a single unrecognized case can trigger a cascade, regardless of whether its origin is naturally occurring or an intentional act. It begins with mandatory public health reporting, emergency management activation, and transfer to a specialized facility all before you have a confirmed diagnosis.

A febrile patient with recent travel from West Africa, the Arabian Peninsula, or other high-endemicity regions warrants a different level of suspicion than the same presentation in a domestic traveler. Knowing where your nearest Regional Emerging Special Pathogen Treatment Center is located and how to activate the referral pathway is another reason to check in with your local public health department.²

After the Final Whistle: The Game Isn’t Over When the Fans Go Home

The tournament eventually ends, and the fans go home, but the public health timeline is just beginning. Because pathogens don't follow the same schedule as the match clock, the postevent period isn't just a few days of heightened alertness; it is a distinct surveillance phase that can extend well into the fall.

What is likely to come first is foodborne illness. Norovirus has an incubation period of 12 to 48 hours, whereas TB can take 8 to 10 weeks to become detectable after infection. The postevent period is not a couple of days. Because the tail of this event is so long, our surveillance can’t stop in the inpatient setting. We need to ensure our outpatient and primary care partners are also screening for “World Cup travel” well into the autumn months to catch those late-presenting cases like TB.

For IPs, the 2026 World Cup isn't just a big event; it’s likely the most complex logistical challenge of the decade. Between the 3-country setup, the flood of international travel, and the reality of high-consequence threats, these 39 days are a massive stress test for our systems. The question is whether our hospitals can pivot in real time or whether a sudden influx of infectious patients will push our capacity to the breaking point.

The demand for live, large-scale sporting events is increasing globally. The foundations that IPs have built for these moments, including clinical familiarity with nonendemic pathogens, active surveillance, and rigorous transmission-based precaution protocols, are our first line of defense. By providing infection prevention refreshers to our clinical teams and cementing our relationships with our public health partners, we enter this summer prepared for whatever walks through our doors.

Enjoy the matches, but keep the various World Cup and biosurveillance dashboards in your peripheral vision to stay current on what is circulating globally. It’s also a good time to ensure your clinical teams—from residents to veterans—are up to date on what mpox or measles rashes look like.

The world is coming. Be ready.

References

1. FIFA World Cup 2026. Fédération Internationale de Football Association. Accessed April 27, 2026. https://www.fifa.com/en/tournaments/mens/worldcup/canadamexicousa2026

2. Mehrotra P, Mathew T, Trulik KG, et al. Sports fever! getting the ball rolling to prevent infections at the World Cup and beyond. Antimicrob Steward Healthc Epidemiol. 2026;6(1):e61. doi:10.1017/ash.2026.10319

3. Tips for STLT Health Officials to Improve Readiness for Potential Public Health Threats Connected to FIFA World Cup 2026. CDC. 2026. Accessed May 1, 2026. https://www.cdc.gov/soccer/index.html

4. Measles data and outbreaks. CDC. Accessed May 1, 2026. https://www.cdc.gov/measles/data-research/index.html

5. Measles and rubella weekly monitoring report. Government of Canada. Updated April 21, 2026. Accessed May 1, 2026. https://health-infobase.canada.ca/measles-rubella/

6. Shams S, Alyafei T, Nafady-Hego H, et al. Gastrointestinal illness among attendees of the FIFA football World Cup 2022 in Qatar. IJID Reg. 2025;14:100493. doi:10.1016/j.ijregi.2024.100493

7. Alhussaini NWZ, Elshaikh UAM, Hamad NA, Nazzal MA, Abuzayed M, Al-Jayyousi GF. A scoping review of the risk factors and strategies followed for the prevention of COVID-19 and other infectious diseases during sports mass gatherings: recommendations for future FIFA World Cups. Front Public Health. 2023;10:1078834. doi:10.3389/fpubh.2022.1078834

Additional Resources

Biosurveillance Dashboards

• Outbreak analytics and disease forecasting. CDC. https://www.cdc.gov/forecast-outbreak-analytics/index.html
• WHO pandemic and epidemic intelligence hub news. World Health Organization. https://portal.who.int/pandemichub/newsmap/
• Brownstein JS, Freifeld CC, Madoff LC; Boston Children’s Hospital. HealthMap. https://www.healthmap.org/en/
• Hadfield J, Müller NF, Bedford T, et al. Nextstrain: real-time tracking of pathogen evolution. https://nextstrain.org/
• Global event maps. GIDEON Informatics. https://app.gideononline.com/visualize/global-events/2026/G100
• Disease events. BEACON: Biothreats Emergence, Analysis, and Communications Network. https://beaconbio.org/en
• Special pathogen biopreparedness map. NYC Health + Hospitals. https://www.biopreparednessmap.org/
• Infectious disease surveillance and outbreak tracking resources. Brown University School of Public Health. https://www.brown.edu/academics/public-health/pandemic-center/

World Cup–Specific Resources

• FIFA World Cup locations. Brown University School of Public Health. https://www.arcgis.com/apps/dashboards/dffc6e18e7a8452490e731f7dee9d11d