Trial Evaluating the Immunogenicity and Safety of an Adjuvanted Epstein-Barr Virus (EBV) Glycoprotein 350 Vaccine in EBV-seronegative Persons

Background: Epstein-Barr virus (EBV) causes most cases of infectious mononucleosis (mono). Mono can cause fatigue that lasts more than 6 months, and some people can have severe complications. EBV infection may also contribute to some cancers and autoimmune diseases. Currently, there are no approved therapies or vaccines for EBV infection. Objective: To test a vaccine against EBV. Eligibility: Healthy people aged 18 to 25 years. Design: Participants will be screened in 2 parts. They will have a blood test. If that test shows they have never had an EBV infection, they will have a second clinic visit. They will have a physical exam, with blood and urine tests. A cotton swab will be rubbed on their gums to collect saliva. Participants will receive 2 injections into a shoulder muscle. Some will receive the EBV vaccine. Others will receive a placebo; this contains harmless salt water with no vaccine. Participants will not know which one they are getting. The 2 injections will be 30 days apart. Participants will be asked to record any side effects or symptoms they have between visits. They can do this on paper or online. Participants will return for a follow-up visit 60 days after the first injection. They will have follow-up visits by phone or telehealth after 5 and 8 months. They will return for a physical exam after 13 months. They may come back for an optional physical exam after 2 years. Participants will come to the clinic if they become ill with an EBV infection during the study.