Visitors from over 200 countries are expected in France for the Olympic Games this year, bringing with them a variety of cultures, traditions, and potentially transmissible diseases.
In September 2023, Paris reported an outbreak of dengue fever that surprised health authorities for two key reasons. First, it was the northernmost documented dengue outbreak. Second, none of the infected individuals had recently traveled, suggesting that local transmission of the disease, which is usually associated with tropical and subtropical regions, is now possible in northern Europe. These alarming events serve as a warning for 2024, when Paris will host the Olympic Games.
It is anticipated that more than 10 million people, including athletes, spectators, officials, and tourists, will come to the French capital for the global event. This large influx of people poses a significant risk for the spread of dengue fever. The French government is aware of this threat and has intensified surveillance and control measures. In Paris, hundreds of locations are regularly checked for the presence of the Aedes aegypti and Aedes albopictus mosquitoes, known carriers of dengue fever.

Nevertheless, the question arises: Will these efforts be sufficient? The presence of so many visitors from various parts of the world could facilitate the spread of the virus if there are gaps in mosquito control or early detection of dengue cases. Moreover, the intense mobility and close interaction between visitors during the Olympic Games significantly increase the risk of a larger outbreak.
To mitigate this risk, the French government and health authorities must implement comprehensive strategies. These include awareness campaigns about dengue fever, encouraging the use of repellents and preventive measures among residents and visitors, and a swift and effective response to early signs of outbreaks. International cooperation will be crucial, with information exchange between countries and global health organizations ensuring a coordinated response.
The Olympic Games in Paris now carry the additional responsibility of addressing a potential health issue alongside being a major sporting event. Continuous monitoring, commitment to public health, and adequate preparation will be essential to prevent dengue fever from becoming a larger global threat during the games.
In Paris, the concern about dengue fever during the Olympics extends beyond direct human-to-human transmission, as dengue is solely transmitted through the bite of infected mosquitoes. However, the concept of super-spreaders remains relevant. In epidemiology, super-spreaders are individuals who, due to specific factors such as social, geographic, or biological behaviors, are more likely to initiate and maintain significant transmission chains of a disease.
Large events like the Olympics, where millions of people from different parts of the world gather, have an increased potential for the introduction and spread of diseases. History shows that even when diseases like Zika and COVID-19 were carefully monitored and controlled within the “Olympic bubble,” the mobility of participants and tourists posed a risk of impact on the local community.
In Paris, the challenge is to ensure that mosquito control measures are stringent, especially given the previous dengue outbreak in the city in 2023. Enhanced monitoring and frequent inspections at vulnerable sites are essential steps in mitigating the risk of super-spreading during the games. Additionally, education campaigns on prevention, the use of repellents, and early detection of symptoms are crucial to protecting both visitors and residents.
While the context of direct dengue fever transmission differs from viruses like Zika or COVID-19, the preventive approach to super-spreaders remains critical for ensuring health safety and minimizing the impact of potential outbreaks during the Olympics.
Given the significant increase in dengue cases worldwide since 2016, the risk of spread during the Paris Olympics is a critical concern. The Aedes aegypti mosquito, which has adapted to the urban environment of the city, is capable of breeding in small amounts of standing water in common urban containers. It prefers to feed on humans during dusk and dawn, which facilitates the transmission of the disease in densely populated areas.
The arrival of visitors from over 200 countries in France for the Olympic Games increases the risk of widespread dengue fever transmission. The presence of susceptible and potentially already infected individuals combined with the availability of transmitting mosquitoes creates a favorable scenario for outbreaks during the event. The ability of Aedes aegypti eggs to survive months of dryness and hatch upon contact with water further adds to the challenge of control.
Therefore, in addition to traditional control measures like frequent inspections and the elimination of potential breeding sites, intensified surveillance and robust preventive strategies are essential to mitigate the risk of the Paris Olympics becoming a global amplifier of dengue fever.
The situation in Paris during the Olympics is particularly dangerous due to the possibility that some Aedes aegypti mosquitoes might already be infected with the dengue virus, which can be transmitted vertically from mother to offspring. This means that these mosquitoes are born with the virus, significantly reducing the number of bites needed to trigger an outbreak.
During the games, a single infected athlete or spectator could be bitten by just one mosquito and trigger an outbreak within about a week. Each female mosquito can lay up to 200 eggs at once, and since most cases of dengue fever are asymptomatic, infected individuals may not know they are carriers of the virus.
These factors greatly increase the potential for rapid and widespread dengue fever transmission in Paris during the Olympics. It is crucial that health authorities implement stringent vector control measures, such as frequent inspections and elimination of mosquito breeding sites, as well as education campaigns to raise awareness among local residents and visitors about dengue fever prevention.
Intensified monitoring and a swift and effective response are therefore essential to prevent the Paris Olympics from becoming a catalyst for a dengue epidemic in the region and beyond.
The situation in Paris during the Olympics is concerning due to the potential for asymptomatic infected individuals to introduce the dengue virus into the city and inadvertently trigger an epidemic. As many dengue cases are asymptomatic, affected individuals might not be aware that they are infected and could unknowingly bring the virus back to their home countries, contributing to the spread of the disease.
This dynamic is similar to the situation at the Rio Carnival earlier this year, where a dengue outbreak shortly before the event raised public health concerns. However, unlike that situation, the Paris Olympics cannot be canceled due to the dengue risk, as the event itself poses a potential risk factor. Every participant in the Olympics—whether a resident, worker, visitor, competitor, volunteer, or merely a passerby—could unknowingly become part of a significant virus transmission dynamic.
Therefore, it is imperative that during the Paris Olympics, strict vector control measures and intensive education campaigns be conducted to prevent the spread of dengue fever. This includes regular inspections to eliminate mosquito breeding sites, raising awareness about the use of repellents, and other preventive measures to reduce the risk of outbreaks during and after the event. International cooperation and a coordinated response among participating countries will also be crucial to mitigating the potential impact of dengue fever during the Paris Olympics.