Top start this June 11. The Football World Cup will bring together millions of people in 16 cities in North America. Between stadiums, airports, hotels, bars, fan zones and public transport, the opportunities for close contact will be countless for more than five weeks.
Ideal conditions for viruses to circulate
For Dr. Gérald Kierzek, medical director of True Medical, the problem is not so much the appearance of a “new pandemic” as the acceleration of already present diseases.
“Large events rarely cause a large epidemic on their own. The main issue is rather that they favor the spread of infections already in circulation and put health systems to the test”he explains.
The phenomenon is not theoretical. Recent history is full of examples: an epidemic of norovirus during the 2006 World Cup in Germany, cases of measles at the Vancouver Olympic Games in 2010 or even infectious outbreaks during the Hajj pilgrimage.
“The danger comes from the combination of high human density, international mobility and the circulation of viruses already present,” summarizes the emergency doctor.
Measles, flu, Covid: the most credible threats of this edition
Among the most closely monitored risks, measles, flu and Covid-19 remain the main concerns of health authorities today.
“The most credible threat to fans is not Ebola, but already known outbreaks of respiratory illnesses,” emphasizes Dr. Kierzek.
Measles particularly worries experts. Very contagious, it can be transmitted extremely quickly in crowded places. And cases are currently exploding in the United States, but also in Canada and Mexico. At the beginning of June, more than 2,000 cases had already been recorded in the United States since the start of 2026. In Kansas City, host city of several matches, the virus was even detected in wastewater before the start of the tournament, a possible sign of active circulation.
“For highly contagious diseases like measles, the risk of transmission is high from the first respiratory symptoms”reminds the doctor.
Covid-19 and the flu also remain under surveillance. The 2025-2026 flu season has reached a 30-year high, while Covid continues to cause hundreds of thousands of hospitalizations each year.
Rarer diseases… but highly publicized
Other more impressive diseases also attract attention, such as Ebola. An epidemic linked to a rare strain is currently affecting certain regions of Central Africa.
But for Dr Gérald Kierzek, this scenario remains much less likely.
“An event like Ebola is considered very unlikely because transmission requires direct contact with biological fluids. We are not at all in the same dynamic as a respiratory virus.”
The United States, Canada and Mexico have also strengthened health checks for travelers coming from the affected areas.
On the other hand, other more discreet risks concern experts: dengue fever, yellow fever, Oropouche virus and even sexually transmitted infections.
Dengue fever, transmitted by mosquitoes, is progressing sharply in certain American regions. As for the Oropouche virus, still little known to the general public, it caused a massive epidemic in Latin America in 2024.
Finally, sexually transmitted infections are also monitored. According to some studies, one in five international travelers have casual sex while traveling, often without protection.
Health preparation deemed insufficient
Beyond the diseases themselves, it is above all the preparation of the United States which worries several specialists. Traditionally, this type of event requires centralized health coordination with a single command center capable of tracking data in real time. However, according to several American experts, this national organization is lacking today.
Federal funding granted to the World Cup mainly concerns security, police or cybersecurity, but very little public health. Several host cities say they have received no additional budget to prepare their hospitals or health services for a possible influx of patients.
Simulations have already highlighted significant difficulties: lack of coordination between cities, problems with rapid identification of cases and limited hospital capacities.
In New York, for example, only two specialized beds are available to treat viral hemorrhagic fevers.
“However, the World Health Organization recommends upstream preparation with epidemiological surveillance, strengthening of healthcare capacities, public health messages and rapid isolation plans”, recalls Dr. Kierzek.
How to protect yourself if you travel?
However, experts want to avoid any panic. With a few simple precautions, individual risk can be greatly reduced.
“The most important thing is to have your routine vaccinations up to date, including measles-mumps-rubella, flu and Covid according to recommendations,” insists Dr Gérald Kierzek.
The doctor also recommends:
- To wear a mask if you have symptoms or in very crowded places;
- Wash your hands regularly;
- To use mosquito repellent in certain regions;
- To avoid unprotected sex;
- And consult quickly in case of high fever, rash, severe diarrhea or breathing difficulties.
“The key point is that the danger is not the event itself”he concludes. “With up-to-date vaccines and simple actions, the individual risk becomes significantly lower.”