The World Health Organization has cautioned that it will be over a year before Zika vaccines are trial-ready. The announcement came amid rising health concerns ahead of the Olympic Games in Rio, which start in August.
Despite ramped-up efforts to find a vaccine for the Zika virus, on Friday the World Health Organization (WHO) announced that it would still take over a year before the vaccines could be tested.
"Our knowledge of what is currently in the pipeline tells us that it will take approximately 18 months before a vaccine can be launched into large-scale trials to demonstrate efficacy," Marie-Paule Kieny, WHO's assistant director-general for health systems and innovation, told reporters in Geneva.
The WHO announced that 15 companies and groups were involved in Zika vaccine research and development, including US government scientists and an Indian biotechnology firm.
The Zika outbreak has affected at least 33 countries - mostly in South and Central America - and was recently declared an international public health emergency by the WHO.
In Brazil, one major site of the outbreak, the rise in cases has also correlated with a spike in microcephaly, or abnormally small heads, in newborn babies. The country is currently investigating the link between the virus and more than 4,000 cases of suspected microcephaly.
"It seems indeed that the link with Zika is becoming more and more probable, so I think that we need a few more weeks and a few more studies to have this straight," Kieny said during the press conference.
Warnings for pregnant women
The WHO has not recommended any general travel or trade restrictions, but announced: "Women who are pregnant should discuss their travel plans with their health care provider and consider delaying travel to any area where locally acquired Zika infection is occurring."
It was the first time the WHO advised women to delay travel plans. Previously, the WHO had only advised pregnant women to protect themselves against virus-transmitting mosquito bites.
The UN health agency announced that the virus was not generally spread by person-to-person contact but cautioned that "a small number of cases of sexual transmission have been documented."
The WHO strongly encouraged people returning from Zika-affected areas to practice protected sex, "including through the correct and consistent use of condoms," but did not specify for how long.
On Friday, researchers at Public Health England reported that the Zika virus was found in the semen of a British man two months after he was infected. The findings suggest that the virus may linger in semen and increase the likelihood of its spread, even after Zika symptoms fade.
Olympic worries in Brazil
Despite growing Zika concerns from Olympic athletes and fans alike, on Friday International Olympic Committee President Thomas Bach said no countries had pulled out of the Summer Games in Rio de Janeiro.
"There is no intention by (any) national Olympic committee to pull out from the Rio Olympic Games," Bach said. "This does not exclude that we are taking this situation very seriously."
"The World Health Organization has not issued a travel ban," Bach said. "All the experts agree that the temperatures in the Brazilian wintertime when the games are taking place in August ... will lead to a very different situation."
A report from Reuters this week showed that mosquito-borne infection cases do not always decline during that season.
rs/jm (AP, AFP, dpa, Reuters)