World Health Organisation assistant director general Marie-Paule Kieny gave an update on development efforts today, telling the assembled journalists that 15 companies are working on vaccines for the mosquito-borne virus.
She said: “Two vaccine candidates seem to be more advanced: a DNA vaccine from the US National Institutes for Health, and an inactivated product from Bharat Biotech, in India.”
Despite the increase in R&D "vaccines are at least 18 months away from large-scale trials” Kieny said, added that "the current absence of standardized animal models and reagents is slowing down development."
WHO efforts to tackle Zika are following the R&D Blueprint created after the Ebola outbreak in 2013.
Kieny said: “We have already identified a large number of manufacturers and research institutions either involved in the development of medical tools for Zika, or interested in embarking on such research.
"Apart from what has already appeared in the press, numerous other groups are looking at the feasibility of initiating animal or human testing, particularly for vaccines and diagnostics."
Zika belongs to a family called the Flaviviridae, which includes the viruses that cause dengue, Chikungunya and yellow fever.
Until recently Zika was thought to be relatively harmless with only 20% of infections resulting in mild, short-lived symptoms such as rash, headache and conjunctivitis.
However, a PAHO report linking the current South American Zika outbreak to an increase in the number of microcephalic babies born in Brazil and Guillain–Barré syndrome (GBS) cases in El Salvador has prompted a reassessment.
Zika was first detected in Brazil last summer (Ministry of Health announcement in Portuguese).
Other countries – including the US - have advised pregnant women to consider postponing travel to the region.
In January the US National Institute of Allergy and Infectious Diseases (NIAID) made grants available to support Zika vaccine research.
The NIAID told us “Several NIAID-supported Zika vaccine efforts already are under way, including live-attenuated vaccines, DNA vaccines and VSV-vectored vaccines. The NIAID Vaccine Research Center is evaluating a DNA approach based on its experience with West Nile Virus.”