Severe acute respiratory disease (SARS) is a recently emerged infectious disease that was first recognized in Guangdong Province, China, in November of 2002. Efforts to prevent the spread of this virus stopped the epidemic in July, 2003, but over 8,000 cases had occurred and almost 800 people died. A new virus, a coronavirus, was shown to be the cause and it is believed to be a virus of bats that infected some animals that, in turn, infected people and they gave it to other people. While it is unlikely to again become epidemic, the virus is thought to be a risk for spread to humans if it was released intentionally by a terrorist group. For that reason, the U.S. government is developing vaccines and drugs for use if spread should occur again. This study will test the safety and protective responses to a vaccine against SARS made by a vaccine company for this study. This protocol concerns Phase I clinical testing of an inactivated, purified SARS Coronavirus (CoV) vaccine administered with and without aluminum hydroxide (Alum) adjuvant. The rationale for development of vaccines against SARS-CoV is to provide a means of control in the event a new SARS-CoV epidemic occurs or there is a deliberate release of the virus. Inactivated SARS-CoV vaccine has been shown to induce neutralizing antibodies that block binding of the virus to its receptor, ACE2. The primary objectives of the study are to assess: reactogenicity of escalating doses of adjuvanted and non-adjuvanted, inactivated SARS-CoV vaccine among healthy young adult subjects given their first intramuscular (IM) vaccinations with this vaccine; reactogenicity of a repeat IM administration of the same material to healthy young adult subjects one month later; and development and persistence of immune responses to escalating doses of adjuvanted and non-adjuvanted, inactivated SARS-CoV vaccine 1 and 5 months after the second ("booster") vaccination. The secondary objective of this study is to assess immune responses to each vaccine 1 month after a single dose. This is a single center, Phase I, out-patient study of the reactogenicity (tolerability and safety) and immunogenicity of escalating doses of an inactivated SARS-CoV vaccine with and without aluminum hydroxide as an adjuvant. Each vaccine will be injected as primary and booster vaccinations a month apart in the subject's non-dominant deltoid muscle. Participants will include 72 healthy males or non-pregnant, non-lactating females, 18-40 years old from the Houston, Texas area. The study will be conducted at Baylor College of Medicine in 2 sequential stages. This study consists of a preliminary dose-escalation stage (1.a, 1.b, and 1.c) followed by a dose comparison stage (2) as follows: Stage 1a (2.5 mcg), 7 subjects randomized in a 1:3:3 fashion to receive a 2 dose regimen of placebo, vaccine containing 2.5 mcg of antigen and no adjuvant, or 2.5 mcg of antigen and Alum adjuvant; Stage 1b (5.0 mcg), 7 subjects randomized in a 1:3:3 fashion to receive a 2 dose regimen of placebo, vaccine containing 5.0 mcg of antigen and no adjuvant, or 5.0 mcg of antigen and Alum adjuvant; Stage 1c (10.0 mcg), 4 subjects randomized in a 1:3 fashion to receive a 2 dose regimen of placebo or vaccine with 10 mcg of antigen and no adjuvant; Stage 2, 54 subjects (9 per vaccine group) randomized 1:1:1:1:1:1 to receive vaccines containing, 2.5, 5.0, or 10.0 mcg of antigen without adjuvant, or 2.5 or 5.0 mcg of antigen with Alum, or placebo.