Phase I clinical trials of a new HIV vaccine developed by researchers at the University of Regensburg in Germany will begin in June in Switzerland and the United Kingdom, Reuters Health reports. The vaccine will be tested in about 160 HIV-negative volunteers to determine its safety profile. Efficacy tests are scheduled for 2005. The vaccine, called DNA-C, uses a two-injection process to produce a protective immune system response by using key HIV genes to prime the immune system to recognize and attack the HIV virus when it tries to enter the body. The initial stage of the clinical trial will give each volunteer only one of the two injections; combination injections will be given to trial participants after the individual safety profiles are established.