A study of an experimental vaccine that aims to provide protection against HIV infection showed poor results among 205 people studied in the United Kingdom and Africa, The Wall Street Journal reports. A protective immune response was detected in only about 20% of the study participants; researchers from Oxford University and Nairobi University had hoped for at least a 60% response. The vaccine was the furthest along of several candidates backed by the New York City-based International AIDS Vaccine Initiative. The vaccine included two shots: one with genetic material from HIV and other with viral material inserted into a weakened version of a virus related to smallpox. The shots were intended to prime the body's immune system to recognize and attack invading copies of the virus. IAVI officials say that development of the vaccine will likely be halted unless new data emerges from the trial that show it to be significantly more effective.