Inclusion Criteria:

1. Signed written informed consent
2. Age 18 - 50 years, inclusive
3. Good general health as determined by a screening evaluation within 30 days before administration of Norwalk VLP Vaccine, adjuvant/excipients or placebo
4. Expressed interest and availability to fulfill the study requirements
5. Agrees not to become pregnant from the time of study enrollment until at least 56 days after the last administration of Norwalk VLP Vaccine, adjuvant/excipients or placebo; if a woman is sexually active and capable of conception (i.e., no history of hysterectomy or tubal ligation), she must agree to use hormonal or barrier birth control. A woman is eligible if she is monogamous with a male who has had a vasectomy.
6. Demonstrated to be an H type-1 antigen secretor
7. Agrees not to participate in another clinical trial with an investigational product for the entire duration of the study (six months after the last study dose i.e. 201 days)
8. Agrees to storage of unused clinical specimens for an indefinite period of time only for those specimens collected by the University of Maryland CVD for use in future research at the CVD. [A University of Maryland site-specific inclusion criterion]

Exclusion Criteria

1. History of any of the following medical illnesses

   • Chronic rhinitis, runny nose, sneezing
   • Clinically significant nose bleed within the last year
   • Diabetes
   • Cancer
   • Heart disease (hospitalization for a heart attack, arrhythmia, or syncope)
   • Unconsciousness (other than a single brief "concussion")
   • Seizures (other than febrile seizures as a child <5 years old)
   • Recurrent infections (more than 3 hospitalizations for invasive bacterial infections such as pneumonia or meningitis)
   • Asthma requiring treatment with inhaler or medication
   • Any current illness requiring daily medication other than vitamins, birth control, or anti-depressant
2. Blood Type B or AB, regardless of Rh + or -
3. Allergies or hypersensitivity to chitosan, shrimp, other shellfish or any component of the vaccine, adjuvant/excipients or placebo
4. History of nasal surgery of any type (including tonsilectomy/adenoidectomy)

5. Any clinically significant abnormality detected on physical examination, including:

   • Murmur (other than a functional murmur)
   • Focal neurological abnormality
   • Hepatosplenomegaly
   • Lymphadenopathy
   • Jaundice
6. Hypertension (BP > 140/90 mm Hg on two separate days)

7. Any lab abnormality, as listed below:

   • Neutrophils (WBC) outside the normal range
   • Hemoglobin outside the normal range (may be repeated once if outside this limit)
   • Platelet count outside the normal range (may be repeated once if outside this limit)
   • Creatinine outside the normal range (may be repeated once if outside this limit)
   • Glucose > upper limit of normal (may be repeated once if outside this limit)
   • AST or ALT outside the normal range (may be repeated once if outside this limit)
   • Positive serology for hepatitis C or HIV antibody or hepatitis B surface antigen
8. For women, positive serum pregnancy test within 7 days and urine pregnancy test within 24 hours of administering either dose of Norwalk VLP Vaccine, adjuvant/excipients or placebo
9. Nursing mother
10. Temperature > 38.0 degrees C (100.4 degrees F) or symptoms of an acute self-limited illness such as an upper respiratory infection or gastroenteritis within 3 days of administration of Norwalk VLP Vaccine, adjuvant/excipients or placebo
11. Previous participation in a study of Norovirus vaccines
12. Medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months
13. Receipt of an investigational vaccine or drug within 28 days before administration of Norwalk VLP Vaccine, adjuvant/excipients or placebo
14. Other condition that in the clinical judgment of the investigator would jeopardize the safety or rights of a subject participating in the trial, would render the subject unable to comply with the protocol or would interfere with the evaluation of the vaccine
15. Failure to pass written examination about this study (70% correct answers required to pass)[A University of Maryland site-specific exclusion criterion]