An open letter has been addressed to the Director-General of the World Health Organization, calling for delay of the upcoming Olympics and Paralympics set to take place in Rio de Janeiro, on the basis of concerns over the Zika virus pandemic. The letter gives examples of other Olympics cancelled in the past, such as in 1916, 1940, and 1944, and argues that a health crisis which has been declared by the WHO to be of international concern, calls for a postponement or change of location. The authors of the letter assert that the situation in Brazil is dangerous enough that cancellation or delay of the games would be of service to public health on a global level.
However, the authors misunderstand some key points with regards to the Zika pandemic. The risks that Zika poses to the games are relatively minimal. The letter compares the Zika situation to other sports events canceled out of concern for SARS and Ebola – however, these comparisons are not apt. SARS was an entirely new pathogen, with uncertain risks, and both SARS and Ebola are high mortality diseases. Zika is not, having very low mortality rates, with deaths related to Zika most frequently caused by the complications related to Guillain-Barre Syndrome, rather than from Zika’s symptoms directly. Guillain-Barre is often triggered by infections, and is thought to be triggered in a small percentage of Zika cases.
The fears expressed in the letter represent a widespread misunderstanding with regards to the nature of the Zika virus, viewing the pandemic as unprecedented and unpredictable. It claims that most of South Asia and Africa remain unaffected by Zika. However, studies from as early as the 1940s have shown people in parts of Africa and Asia to possess antibodies to Zika, and other evidence suggests that it has circulated in West Africa and Southeast Asia as recently as in the last ten years. There is strong evidence that antibodies from these instances of previous exposure will protect against the fairly similar Brazilian version of the virus.
Brazil is already home to a number of more clinically threatening diseases also found in much of the tropical world, including malaria, dengue, and HIV. None of these diseases have been cited as reason to cancel or delay the Olympic games.
No event is entirely guaranteed to be safe, and those predisposed to Guillain-Barre syndrome, as well as those who are pregnant or planning to get pregnant, should not travel to Brazil. Certain precautions should be taken by those who do choose to attend, including abstaining from unprotected sex for 60 days after their return from Brazil. If these and other precautions are taken, there is no reason why the Rio Olympics are any more dangerous than a large event in any other tropical country.