Indian biotechnology company Bharat Biotech said on Wednesday it was working on two possible vaccines to fight the Zika virus, which has been linked to birth defects in thousands of babies in Brazil.

The virus is spreading rapidly in the Americas, and WHO officials on Tuesday expressed concern that it could hit Africa and Asia as well. No vaccine has been developed so far.

One of the possible vaccines is "recombinant", which means it is created by genetic engineering, while the other was "inactivated", and will enter pre-clinical trials in animals in two weeks, Bharat Biotech managing director Krishna Ella told Reuters.

An inactivated vaccine is created by killing a pathogen in a way that its ability to replicate is destroyed, but the immune system can still recognise it.

Bharat Biotech's announcement came a day after France's Sanofi said it had launched a project to develop a Zika vaccine. On Wednesday, Japanese drugmaker Takeda Pharmaceutical also said it was investigating the possibilities of developing a vaccine for the disease.

Privately held Bharat Biotech, based in the southern town of Hyderabad, said it started work on the Zika virus a year ago, while developing vaccines for chikungunya and dengue. Zika is closely related to dengue and is spread by the same species of mosquito.

Bharat Biotech sells its vaccines for polio, hepatitis B, H1N1 and rabies, among others, to more than 65 countries, according to its website.

"They've got a lead, essentially ... it's certainly not a vaccine yet," said Soumya Swaminathan, the director general of the Indian Council of Medical Research (ICMR), the apex body for biomedical research in India, funded by the health ministry.

Swaminathan said it was premature to comment on the two vaccine candidates, but the ICMR had put together a group of experts to examine their validity.

No cases of the virus have been detected in India yet, but the health ministry on Tuesday issued guidelines on the disease, including an advisory that travel to affected countries be postponed or cancelled.  - Reuters