Four companies have developed potential vaccines and plan clinical studies.

Other companies are also working on potential vaccines, as are scores if not hundreds of researchers at institutions around the world.

Still other potential vaccines are being tried in Europe and Africa.

Twenty other potential vaccines are still being developed.

Scientists have developed a potential vaccine for Alzheimer's disease.

There is no solid data yet to confirm the reason this occurs, but information of this kind can spark research interest in a potential vaccine.

Nexvax2 is a potential vaccine for celiac disease created by ImmusanT.

A number of potential vaccines are currently being tested.

There are a number of considerations to be made concerning what strategy a potential vaccine should adopt.

Other potential vaccines are being tested in chimpanzees as a prelude to possible human studies.