The World Health Organization (WHO) has said postponing the upcoming Olympic Games in the Brazilian city of Rio de Janeiro would "not significantly alter" the effect of the virus.
The WHO statement came after a letter by top international health experts and scientists called for the postponement or change of venue for the event to avoid further spread of the Zika virus. The Olympic Games are scheduled from August 5 to August 21 of this year.
The letter, which has 150 signatures from doctors, scientists and bioethicists, says, “WHO must revisit the question of Zika and postponing and/or moving the Games.”
“We recommend that WHO convene an independent group to advise it and the IOC [International Olympic Committee] in a transparent, evidence-based process in which science, public health, and the spirit of sport come first.”
The Zika virus began spreading in Brazil during 2015.
It has been linked to more than 1,400 confirmed cases of microcephaly, a rare birth defect that causes babies to be born with abnormally small heads and developmental problems.
Experts say it may also cause Guillain-Barre, a rare and sometimes fatal neurological syndrome in adults.
The mosquito-borne disease was declared an international public health emergency by WHO in February.
It has already spread to almost 60 countries, predominantly in Central and Latin America.
The letter says "An unnecessary risk is posed when 500,000 foreign tourists from all countries attend the Games, potentially acquire that strain, and return home to places where it can become endemic."
“Should that happen to poor, as-yet unaffected places (e.g., most of South Asia and Africa) the suffering can be great.”
In May, the International Olympic Committee (IOC) said that there is no reason to delay or move the Games due to Zika.
The IOC's partnership with WHO raises concerns that it may affect the health organization's stand on the issue.
Recently, Tom Frieden, the director of the Centers for Disease Control and Prevention, said the agency does not see any reason to cancel the Olympics.
"There's been some claims that if the Olympics happen, it's going to disseminate the virus everywhere, it's going to amplify it. Well, we looked at the numbers. The Olympics account for less than one quarter of 1 percent of all travel to Zika-affected areas."
However, concerns over the Zika virus have already prompted Major League Baseball to cancel a series of games due to take place in Puerto Rico. USA Swimming has also moved its pre-Olympic training camp to Atlanta.
No Olympic Games have ever been moved in the past from the host city due to medical concerns.