Rio de Janeiro (CNN)Rio's Olympic organizers went on the offensive Tuesday, trying to drown out the voices that insist the Zika virus poses a health risk for the 2016 Summer Games.
Zika and Olympics: Rio organizers say Games are safe
At a press conference, organizers put up slides showing that the number of Zika cases has fallen quickly as Rio has moved into the colder winter months. So has the number of other mosquito-borne viruses like Dengue fever and chikungunya.
"We are 110% comfortable that we can protect everybody that expects to see the games," said Mario Andrada, director of communication for Rio 2016.
Last month, 150 scientists and doctors posted an open letter arguing the 2016 Summer Games should be postponed or moved.
"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," they wrote.
But on Tuesday, the chief medical expert for Rio 2016 cited a study that says the most likely scenario during the 2016 Olympics is that Zika will affect 1.8 people per 1 million tourists.
In Brazil, doctors said the virus has caused a huge uptick in serious birth defects. The Health Ministry has confirmed 1,489 cases of Zika-related microcephaly since the virus was detected in the country. It is investigating more than 3,000 suspected cases.
The WHO advises pregnant women to avoid areas with Zika and says people returning from areas with Zika should adopt safe-sex practices for at least eight weeks upon return.
While there appears to be disagreement within the medical community, WHO has downplayed the risks of the Rio Olympics sparking a global epidemic.
"Canceling or changing the location of the 2016 Olympics will not significantly alter the international spread of Zika virus," WHO said.
"Brazil is one of almost 60 countries and territories which to date report continuing transmission of Zika by mosquitoes. People continue to travel between these countries and territories for a variety of reasons. The best way to reduce risk of disease is to follow public health travel advice."
Brazilian officials have argued the risk of infection is seriously reduced during the Games, because they are being held in the South American winter month of August, when mosquito populations tend to die.
According to Rio's health secretariat, the number of Zika cases has already declined significantly. According to their figures, the city has seen a total of 26,576 cases of Zika so far this year, with a peak in February of 7,232 cases. In May, there were 702 reported cases.
But the Rio games are getting hammered by negative publicity when it comes to the Zika virus.
NBC anchor Savannah Guthrie announced on Tuesday that she is pregnant and won't be coming to the city to cover the Olympics over Zika fears. A string of athletes have also expressed concern, with some pulling out.
American Cyclist Tejay van Garderen is one of them. He told CNN's Robyn Curnow, "If my wife wasn't pregnant, right now, I'd be going to Rio. My biggest concern is for the baby on the way. I would never tell any athlete who's worked their butt off for four years not to go to the games."