The WHO says institutions in the US and India are leading the global race to find a way of immunising against the mosquito-borne disease
A ZIKA virus vaccine is at least 18 months away from large scale clinical trials, the World Health Organisation (WHO) said on Friday.
The WHO said institutions in the US and India were leading the global race to find a way of immunising against the mosquito-borne disease, which is expected to be officially linked to the birth defect microcephaly within weeks.
WHO officials said doctors were closing in on establishing the relationship between Zika and microcephaly, which causes babies to born with abnormally small heads.
The organisation also recommended for the first time that pregnant women consider delaying travel to affected countries.
“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,” said Marie-Paule Kieny, WHO assistant director-general for health systems and innovation.
A link with Guillain-Barré syndrome, a rare neurological disorder in adults which causes muscle weakness and paralysis, was also likely to be confirmed, she added.
Dr Kieny said there were 15 institutes around the world working on a Zika vaccine, including teams in Brazil.
“Two vaccine candidates seem to be more advanced: a DNA vaccine from the US National Institutes for Health (NIH) and an inactivated product from Bharat Biotech in India,” she added.
For the first time, the WHO added its voice to calls from the UK, US and others that pregnant women should consider delaying travel to areas where Zika was present.
On Thursday, Brazil’s Health Ministry announced a partnership with the University of Texas to develop a vaccine, which Marcelo Castro, health minister, said he hoped would be trialled within two years.
The research will be shared between Texas and Brazil’s Evandro Chagas Institute, which will carry out trials of the vaccine on monkeys in the Amazonian city of Belem.
“The idea is that the first pre-clinical trials in the first year will be simultaneously carried out in Brazil and the United States,” said Pedro Vasconcelos, researcher at the Evandro Chagas Institute.
“This simultaneous testing will give more speed to the process, allowing clinical trials to begin within the second year.”
Meanwhile, researchers at São Paulo’s Unicamp university have developed a test for Zika that provides results within five hours.
“It’s a very important test, because imagine a pregnant woman who is sick. She may have flu, dengue, some other viruses, but today the biggest fear is Zika. Then I do the test and it is negative for Zika. Imagine the relief that person, said Clarice Arns, researcher at Unicamp’s Institute of Biology.
Earlier this week, mounting medical evidence suggested doctors were close to concluding that Zika was responsible for a spike in Brazilian cases of microcephaly, after the virus was found in the brain tissue of babies with the impairment who had died.
Research showing similar evidence was published both by scientists in Slovenia and separately by the US Centers for Disease Control and Prevention (CDC).
“This shows that the virus is able to cross the blood-brain barrier,” Dr Arns added. “It’s a very important result, but still remains necessary to scientifically establish a cause and effect relationship between Zika and microcephaly.”
Yesterday, Public Health England said researchers had been found in the semen of a British man two months after he was first infected, suggesting the virus may linger in the semen long after symptoms of the infection fade. The United States has reported one case of apparent sexual transmission in a Texas resident found to have contracted the virus from their partner who had returned from Venezuela.