The US Food and Drug Administration has given the green light for testing of a new experimental DNA-based Zika vaccine developed by Inovio Pharmaceuticals. In cooperation with its partner GeneOne Life Science, Inovio said it plans to begin a 40-person study to determine the safest dose of the vaccine in coming weeks. First results are expected by the end of the year.

If successful, the tests will put Inovio ahead of researchers at the US National Institutes of Health (NIH), who expect to begin testing their own DNA-based Zika vaccine this autumn. It will also give the company a head start in competition with international drugmakers such as Sanofi who are developing their own vaccines against the mosquito-borne virus.

The Inovio product is designed to boost the immune system by introducing genetically-engineered material that mimics the virus. Animals tested with the vaccine are said to have developed antibodies and immune-system cells that attack Zika. NIH is working to develop a vaccine by swapping out the genetic material from its experimental West Nile virus vaccine.

Currently, there are no licensed drugs or vaccines for this new virus. Ultimately, health officials said, any vaccines or treatments will require large studies, and how fast those could be done will depend in part on how fast Zika spreads.