With an astounding death toll and thousands still being affected on a daily basis, there is an evident and urgent need for a vaccine against the lethal Ebola virus that is sweeping West Africa. Experts from global health agencies are saying that hundreds of thousands of doses of the potential vaccine is required to provide protection just to the health workers that are working on the frontlines during Vegas global health crisis. At least 12 million more are needed to vaccinate the people within the three hardest-hit countries in the region, which are Sierra Leone, Liberia and Guinea.

Now, as pharmaceutical companies race against time in an effort to come up with a formulation that could help bring the outbreak under control, three experimental formulations have shown promising results in the fight against Ebola. These vaccines are now being tested on human subjects based on an accelerated timeline due to the unprecedented crisis.

Pharmaceutical giant GlaxoSmithKline has developed a well-tolerated vaccine that was proven to be effective when tested on 20 healthy volunteers within the United States. Plans for a larger-scale testing is in the works for this formulation called cAd3-EBO.

The Johnson&Johnson Company, in collaboration with the NIH and Bavarian Nordic, is also developing a two-shot vaccination system against Ebola - the first one prepares the immune system, and the second one boosts immune response. Preliminary testing that was carried out on volunteers within the United Kingdom has already begun and will proceed on a more extensive scale moving forward, ideally by April 2015.

After a slight setback, phase 1 trial for the VSV-ZEBOV vaccine from Merck is back on track, with the trials taking place in Switzerland. This formulation is synthesised from an animal virus called the vesicular stomatitis virus that has been genetically altered to carry the genetic code for Zaire Ebola virus.