Thomas Geisbert and colleagues now report promising results with a replication-competent vaccine based on attenuated recombinant vesicular stomatitis virus vectors expressing the Lassa viral glycoprotein.

A recombinant vaccine against Lyme disease, based on the outer surface protein A (OspA) of B. burgdorferi, was developed by GlaxoSmithKline.

Subsequent development of vaccines based on the bacterium's polysaccharide capsule, which could protect against infection, confirmed that an endogenous antibody response can provide protection against invasive disease.

Certain groups of people were targeted to receive initially limited supplies of the vaccine based on data indicating they were at higher risk for infection or for severe influenza complications.

Newer vaccines, based on vero cells, are in development and should replace 17D at some point.

The new vaccine, based on an inactivated polio virus but with enhanced potency, is approved for general use and is often used to prevent polio in people with immune disorders.

Thomas Geisbert and colleagues have developed and now report tests of a recombinant vaccine based on a replication-competent vesicular stomatitis virus (DOI: 10.1371/journal.

Experiments with genetic engineering of a vaccine based on F1 and V antigens are underway and show promise.

But a genetically engineered animal vaccine, the first vaccine based on recombinant DNA ever released into the environment in this country, offers hope that the plague can be kept at bay.

These work of Sela have led to the discovery of the genetic control of the immune response, as well as to the design of vaccines based on synthetic molecules.