Paris 2024 Olympics and Paralympics: assessing risks of novel COVID-19 variants, dengue, and other infectious diseases

Dear Editor,

The major international sports event “Paris Summer Olympics 2024” began on July 26 and will end on August 11, 2024. For 19 days, athletes from all over the world participate in 329 events, with about 10,500 participants from 206 national committees, including the Refugee Olympic Team. Millions of people are expected to participate, including athletes, support staff, volunteers, journalists and spectators. Officials expect to welcome nearly 15 million visitors, including 2 million international tourists (https://www.cbsnews.com/news/2024-paris-olympics-covid-cases-organizers-seem-unfazed-outbreak-risk/).

France is experiencing an unprecedented sporting spirit, with some 320,000 people watching the spectacle of the opening ceremony live from the quays of the Seine, not to mention those enjoying the spectacle from their windows overlooking the river. The Olympics offer athletes a global platform to showcase their incredible stories. Sports events are unique in their ability to promote a better world, and Paris is welcoming people from every corner of the globe. In addition, sports fans are attracted to France’s iconic venues, such as the Eiffel Tower and the Grand Palais. Major sporting events significantly stimulate the national economy, influencing sectors such as sportswear, tourism, catering and logistics. The more than 10-kilometer Olympic village features 35 venues and 14 locations hosting 24 sporting events. The Paris Olympics use locations such as Yvelines, Hauts-de-Seine, Seine-et-Marne, Seine-Saint-Denis, Bordeaux, Nantes, Lyon, Saint-Étienne, Nice, Marseille, and Tahiti. Each site hosts various events, including soccer, surfing, and sailing. The Paris 2024 Paralympics, on the other hand, will take place from August 28 to September 8, 2024. This correspondence article highlights the risks of possible global spread of the novel COVID-19 variants, dengue and other infectious diseases during such mega events.

This study involved a comprehensive literature review, data analyses of the reported epidemiological instances, validated sources related to public health, and relevant global case studies regarding infectious diseases and potential risks associated with major sporting events. Quantitative data on the recently circulating COVID-19 variants, dengue cases and other infectious diseases were collected from reliable health-related global agencies and organizations, and the databases for risk assessment. It also suggests the numerous countermeasures to prevent the possible global spread of these.

However, with the large turnout and busy schedule of events, crucial epidemiological considerations also emerge. WHO has warned that the virus behind the COVID-19 pandemic is still circulating. Data from 84 countries show that the rate of positive tests for SARS-CoV-2 has been rising for several weeks, with positivity rates above 10% worldwide, but in Europe the figure exceeds 20%. These emerging cases have created a potential scenario for another wave of COVID-19 worldwide if timely health interventions and public awareness and participation are not ensured. Given the growth trajectory of COVID-19 globally, existing guidelines may need to be revised to ensure safety during the event, such as verifying that travelers are fully vaccinated against COVID-19 in their home countries, with testing and vaccination reports verified at entry points such as airports and immigration centers in Paris. Recently, the virus has affected several sporting events, including the Tour de France (June–July 2024), where five of the 176 riders officially withdrew due to COVID-19. According to the last data (https://www.france24.com/en/live-news/20240806-olympics-sees-40-plus-covid-cases-as-global-figures-rise-who), more than 40 athletes at the Paris Olympics have tested positive for COVID-19, which persists at a low level, but vigilance remains key because current vaccines have low efficacy against recent variants such as JN.1^[1^]. Sub-strain KP.2 (an offshoot of JN.1) is associated with increased cases in France and other countries. This variant is more immune-evasive but does not cause more severe disease (https://www.lemonde.fr/en/environment/article/2024/06/20/covid-19-increased-viral-circulation-boosted-by-new-kp-2-sub-variant_6675228_114.html). According to the European Respiratory Virus Surveillance Summary (ERVISS) system (Fig. 1), as of July 14, 2024, the KP.3 variant accounts for approximately 33% of sequences (n = 45) in France, with BA.2 representing 60% and the remaining 6.7% categorized as “Other” variants. Although data on these strains are currently limited^[2,3^], the mutated spike protein may allow the virus to evade vaccine-induced immunity and immune responses from previous infections, potentially leading to infection and reinfection. Despite this, SARS-CoV-2 variants are not causing particular problems at the Paris Games, but the risk of new emerging variants that could have an impact in the future cannot be ruled out.

Figure 1.

Weekly distribution of SARS-CoV-2 variants in France from January 1 to July 14, 2024. Source: The European Respiratory Virus Surveillance Summary (ERVISS) (https://www.ecdc.europa.eu/en/publications-data/european-respiratory-virus-surveillance-summary-erviss, accessed on 2024-08-07).

Major sporting events such as the Olympics present an increased risk of multiple infectious diseases. The Paris 2024 Olympics, require special attention not only for the risk of a new wave of COVID-19, but also for other emerging infectious diseases, such as the ongoing mpox epidemic in Kenya and the Central African Republic (https://apnews.com/article/mpox-kenya-central-african-republic-outbreak-disease-7da16b2ccad88b7580318322bb0798ed) and dengue, which has been a significant increase in the presence of dengue vectors (Aedes aegypti and Aedes albopictus) throughout Europe^[4^]. Geographic expansion of the invasive tiger mosquito (Aedes albopictus) has also been reported in France^[5,6^]. As the climate warms, Europe’s hot summer creates favorable conditions for the growth of these species. Notably, the 2016 Rio Olympics in Brazil were nearly postponed due to the fear of Zika (another virus transmitted by Aedes mosquitoes), the 2020 Tokyo Olympics were postponed due to COVID-19, and now the 2024 Paris Olympics face the potential threat of dengue. According to the last bulletin of the French national public health agency (https://www.santepubliquefrance.fr/maladies-et-traumatismes/maladies-a-transmission-vectorielle/chikungunya/articles/donnees-en-france-metropolitaine/chikungunya-dengue-et-zika-donnees-de-la-surveillance-renforcee-en-france-hexagonale-2024) metropolitan France experienced a sharp rise in imported dengue cases in early 2024, with 2166 cases reported between January 1 and April 30 – far exceeding the 5-year average of 128 cases for the same period. The majority (82%) originated from Martinique and Guadeloupe, reflecting severe epidemics in these French overseas territories. Fig 2 illustrates the regional distribution of these cases in metropolitan France. From May 1 to July 30, an additional 934 imported dengue cases were reported (Fig. 2A), mostly in regions where Aedes albopictus mosquitoes are present. Martinique, Guadeloupe, and Indonesia were the primary sources of these cases. During the May–July period, nine imported chikungunya cases (mainly from the Ivory Coast) and two Zika cases (from India and Thailand) were also recorded (Fig. 2B and C, respectively), predominantly in areas with Aedes albopictus presence. Ile-de-France reported the highest numbers across all three diseases (184), followed by Auvergne-Rhône-Alpes (123) and Provence-Alpes-Côte d’Azur (109).

Figure 2.

Regional distribution of imported (A) dengue, (B) chikungunya, and (C) Zika cases in metropolitan France from May 1 to July 30, 2024.

Vector control measure seems to be an effective approach to address the issue of vector-borne diseases^[7,8^]. Combating the vectors through the use of effective insecticides that prevent the development of resistance to alternative insecticides is a critical component^[9^]. Some vectors have been reportedly relatively resistant to dicloro-difenil-tricloroetano and permethrin insecticides. It was recommended to conduct studies on the prevalence of the knockdown resistance (kdr) gene in such vectors owing to their region-wise differential resistance^[10^].

Large gatherings during these events can pose a risk of infection for hepatitis A virus, hepatitis B virus, and measles^[11,12^], especially for people with predisposing medical conditions, such as advanced age and co-morbidities, including cardiovascular disease and chronic kidney disease. Given the high risk of multiple infectious diseases, it is critical to implement effective preventive measures, such as rigorous health surveillance, regular testing, targeted vaccination campaigns, and timely information to the public on behaviors to reduce the spread of disease. Promoting hand hygiene, the use of face masks, and social distancing where possible can make a big difference. Health authorities could effectively use social media to disseminate information in real time and set up an emergency hotline for sports fans traveling to the site. This would provide access to up-to-date health information, highlight associated risks, outline serious implications, and inform about available health services. Public health awareness campaigns should be organized to educate the public on appropriate prevention and control measures to avoid any unusual patterns of infection. The COVID-19 pandemic has changed many scheduled medical activities with restricted access to healthcare facilities^[13^]. As the current COVID-19 vaccines do not fully address the problem of infection and reinfection, implementation of these preventive measures is critical^[14^]. Newly emerging variants of SARS-CoV-2 must be carefully monitored through regular screening of isolates using next-gen sequencing.

The analysis presented does not address limitations related to data collection, such as potential bias in reported COVID-19 cases and the impact of underreporting. In addition, varying public health policies between countries could also affect generalization of the results with expected outcomes. The study does not take into account the mental health implications of the pandemic and the resulting impact on the athletes and spectators during such mega events.

It is crucial to ensure adequate health facilities to deal with any health problems on site, as well as well-equipped hospitals to handle emergency cases. In addition, it is crucial to develop new vaccination strategies, improve the efficacy of vaccines against new variants of the virus, and discover more efficient monoclonal antibodies and specific antimicrobial agents to control infections. These advances could play a key role in curbing the spread of infectious diseases and mitigating the associated risks. In a predictive microbiology strategy, microbial surveillance of the environment, including water and air, can provide valuable data on prevalent microorganisms. This information can help predict future emergencies and intervene before situations escalate, improving the ability to respond to and prevent outbreaks. The combination of environmental monitoring, innovations in vaccine technologies^[15^], and proactive health management is essential to ensure the safety of participants and visitors during large-scale events such as the Olympics, while minimizing the risk of an adverse health impact. This article could help the governments and community healthcare authorities to analyze the associated risks during such future mega events or mass gatherings, predict the risks well, and address unusual patterns well in advance.

Ethical approval

Not applicable.

Consent

Not applicable.

Sources of funding

All the authors declare to have received no financial support or sponsorship for this study.

Author contribution

R.K.M.: conceptualization; R.K.M., F.B., V.K., M.S., N.K.B., S.S., R.N.S.: writing the manuscript; S.M., L.S.T.: edited the final manuscript. All authors have critically reviewed and approved the final draft and are responsible for the content and similarity index of the manuscript..

Conflicts of interest disclosure

All the authors declare to have no conflicts of interest relevant to this study.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Francesco Branda, Ranjan K. Mohapatra.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Data availability statement

Data are available with the manuscript.