People traveling to Brazil for the Olympic Games next month can breathe a little sigh of relief as a team of researchers has claimed that the risk of international spread due to the event is low.
In a worst-case scenario, an estimated 3 to 37 of the thousands of athletes, spectators, media and vendors traveling to Rio for the Olympics will bring the Zika virus back to their home countries, the researchers at Yale School of Public Health (YSPH) concluded.
The findings support the position of the World Health Organization, which has said that travel to and from the Olympics will not play a significant role in the international spread of Zika. However, the findings are contrary to a recent recommendation by 150 members of the international academic community to cancel or relocate the Games on the grounds of preventing the spread of Zika. Some athletes have also said they will not travel to Rio to compete due to health concerns associated with Zika.
"It's important to understand the low degree of risk posed by the Olympics in the scheme of many other factors contributing to international Zika virus spread," said lead author Joseph Lewnard.
Lewnard, along with researchers Albert Ko and Gregg Gonsalves, constructed a mathematical model that accounted for recent Zika transmission in Rio de Janeiro, seasonal conditions and travel patterns, among other factors.
Over half of visitors attending the Olympics are expected to return to high-income countries where there is negligible risk for establishing local spread of the virus, say the researchers. Around 30 percent will travel to Latin American countries where transmission is already established, so they will not play an important role in further spreading the virus, they note.
"This study provides data, which together with initial findings from Brazilian scientists, show that these concerns may be largely exaggerated," said Ko.
It is projected that the Olympic Games could draw as many as 500,000 visitors to Rio, where it is currently winter and mosquito activity has subsided. The mosquito-borne Zika virus arrived in Brazil about two years ago and has since spread rapidly throughout the country and much of the hemisphere.
The disease is associated with microcephaly, a congenital disorder marked by a smaller-than-average head, as well as Guillain-Barre syndrome, an autoimmune condition. Many who are infected exhibit mild symptoms or no signs of illness at all.
Lewnard said that it is important that policymakers and the public have accurate information about health concerns associated with travel to Brazil.
The findings are published online in journal Annals of Internal Medicine.
