The obvious unknown is the symptomless cases: Can the virus remain transmissible after the return of an athlete or visitor to the games? This is a crucial point and helps explain where there are still a number of misunderstandings. While in Brazil’s population there are some symptomless cases, people from abroad with no prior exposure to Zika virus (and therefore no resistance), would certainly have some symptoms. This remains true for both North Americans and Europeans, and so they are at no risk of further spreading the virus 1 month after their return from Brazil – should they not present any symptoms.
In one recent case of overkill, Kenya threatened to boycott the Summer Games entirely on safety grounds, a move clearly based on no identifiable scientific evidence, as the risk for athletes alone remains very low and fundamentally manageable. Conversely, the other controversial advice I have recently seen stems from the World Health Organization itself – which suggested women in Latin America should not put off pregnancy for fear of Zika. But until more information is known, and the RNA is properly analyzed or a vaccine becomes available, this is not a position I can yet support. We need to fully understand the risks of Zika virus infection, and there is still a long way to go.
Prof. Dr. Eskild Petersen is a member of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) study group for Infections in Travellers and Migrants (ESGITM) as well as a professor of tropical medicine at Aarhus University Hospital, Denmark, and senior consultant of infectious diseases at the Royal Hospital, Muscat, Oman. He has undertaken work on infectious diseases, clinical immunology, and tropical and travel medicine. His recent research focuses on the rapid spread of Zika virus in the Americas and the implications for the 2016 Rio Olympic Games.