The head of the WHO's Zika expert panel David Heymann said in Geneva the "risks are no different for people going to the Olympics than for other areas where there are outbreaks of Zika."

"The Committee concluded that there is a very low risk of further international spread of Zika virus as a result of the Olympic and Paralympic Games as Brazil will be hosting the Games during the Brazilian winter," when intensity of transmission through mosquitoes will be minimal, he added.

Heymann was speaking to reporters Tuesday following the emergency committee's third teleconference.

The WHO insisted there should be no travel ban to Brazil in response ot the current outbreak but called on Brazil to "continue its work" to intensify mosquito-control measures, especially around the Olympics venues.

Health officials on the defensive

This is the second time the WHO has affirmed its position in the face of criticism by some 200 health experts who have demanded that the games should be postponed or relocated because the masses attending it could spread the virus abroad. Brazil has been the hardest hit by the current outbreak.

Brazilian authorities have confirmed more than 1,400 cases of microcephaly in babies whose mothers were exposed to Zika during pregnancy.

Microcephaly is a birth defect marked by small head size that can cause severe developmental problems in babies.

Pregnant women have been told to avoid travel to Zika outbreak areas and men who have been exposed to the virus should practice safe sex for up to six months.

The 2016 Olympics in Rio are due to begin on August 5, with the Paralympic Games following in September.

The WHO has previously blamed policy failure for the spread of the virus.

Invitation rescinded

Meanwhile, one of the leading critics of the WHO's policy on Zika said Tuesday he was invited to sit on the agency's emergency committee, only to have his invitation withdrawn when he refused to sign a confidentiality clause.

Canadian professor Amir Attaran said he was surprised by the decision saying he "thought it would be a good opportunity to have a full discussion of the concerns around Zika and the Olympics." He said an insistence to keep scientists from repeating their own input to the meetings was unjustified.

The WHO said Attaran did not agree to the standard confidentiality form required of all experts, so he was not issued a formal invitation.

mm/bw (AP, dpa, Reuters)