CDC Situation Assessment Suggests Travel to Olympics Poses No Risk of Zika Exportation

With the 2016 Rio Olympic Games less than one month away, the Centers for Disease Control and Prevention (CDC) released a statement summarizing their assessment of the risk of Zika importation by those returning from the summer Games.

The Zika situation in Brazil has been bleak since the outbreak was first reported in May 2015. According to a document released by the CDC, the centers first issued a travel warning advising against travel to South America and Mexico, due to the Zika outbreak, in December 2015. Since the start of the outbreak, the Brazil Ministry of Health reported an increase of Guillain-Barré syndrome (GBS) cases, most of whom were diagnosed with Zika. The CDC is currently investigating this link. Although there is active Zika transmission in Brazil, not all those diagnosed with the virus were infected through the mosquito vector; many individuals have been confirmed to have been infected through sexual intercourse with an infected male, and there have even been several reports of infection through contaminated blood transfusions. This comes as no surprise, since approximately 3% of blood donors tested positive for the virus during the 2013-2014 Zika outbreak in French Polynesia.

Perhaps the most terrifying outcome associated with a Zika infection is the possibility of Zika virus congenital syndrome. A recent study, published in The Lancet in late June, found that not all babies that were infected with Zika during fetal stage will have physically-distinctive attributes. The authors stated that, because of this, testing for microcephaly can no longer adequately confirm that a fetus has suffered neurological complications as a result of a congenital Zika infection. In an Epidemiological Situation report released by the European Centre for Disease Prevention and Control (ECDC), Brazil has reported a total of 1,656 confirmed cases of microcephaly (a number that the study authors believe to be under-reported) between October 2015 and July 7, 2016. Due to this threat, several Olympians have publicly announced their withdrawal from the Games.

Statement on my Olympic Games participation pic.twitter.com/KY4YBzFa3g

— Shane Lowry (@ShaneLowryGolf) June 28, 2016

While Zika has stirred some fear among those who were planning on competing in or attending the summer Games, it has also raised concerns on national levels. With travel to an area with active Zika transmission comes the risk of contracting the virus and spreading it throughout an individual’s native country upon return from Rio. With the Northern Hemisphere going into warmer climates, this was thought to pose a risk of spurring active transmission in countries that have not yet been affected.

According to the CDC, the Brazilian Tourism Board has estimated that the summer Olympic Games will see approximately 350,000-500,000 visitors from around the world, including athletes from 207 countries. Nonetheless, the CDC confirms that those traveling to Rio for the Games “are expected to have a low probability of mosquito-borne Zika infections because the Games will occur during winter season in Rio de Janeiro (August 5-21 and September 7-18, respectively) when the cooler and drier weather typically reduces mosquito populations.”

The CDC estimates that those countries at greatest “risk for travel-associated exportation of Zika virus… exclusively attributable to the Games,” are Chad, Djibouti, Eritrea, and Yemen. This, the CDC states, is due to the small level of civilian travel to Zika-infected areas, as well as “environmental conditions and population susceptibility to sustain mosquito-borne transmission of Zika virus.”

The CDC recommends that all individuals planning to travel to Rio de Janeiro for the summer Games take the necessary infection prevention precautions during their trip, and refrain from actions which may allow for spread of infection (such as sexual intercourse- especially with a pregnant woman or a woman planning to become pregnant) for up to 3 weeks after returning from Brazil. Nonetheless, the CDC still advises that pregnant women should not travel to Brazil for the summer games.

In addition, all pregnant women and their sexual partners should refrain from travel to St. Eustatius, as the CDC has placed a level 2 travel notice for the island, due to active Zika transmission. For a full list of CDC travel notices, visit the CDC website.