Efficacy and Safety of Nitazoxanide in the Treatment of Colds Due to Enterovirus/Rhinovirus Infection

Inclusion Criteria: 1. Male and female subjects at least 12 years of age 2. Presence of clinical signs and/or symptoms consistent with an acute illness compatible with EV/RV infection (each of the following is required): 1. Presence of moderate or severe rhinorrhea defined as "attempting to relieve nasal symptoms by blowing, wiping, or sniffling at least twice per hour for any one hour within 12 hours preceding study entry," AND 2. Presence of cough, sore throat or nasal obstruction. 3. Negative rapid influenza diagnostic test (required only if the subject has an oral temperature \>100°F in the clinic or if the latest CDC weekly influenza report shows influenza prevalence "Regional" or higher for the institution's state). A result from a rapid influenza diagnostic test performed on the same day that informed consent is obtained will be sufficient to meet this criterion if documentation of test results is available as part of medical history. 4. Onset of illness no more than 40 hours before enrollment in the trial. Onset of illness is defined as the first time at which the subject experienced rhinorrhea, cough, sore throat or nasal obstruction. 5. Willing and able to provide written informed consent (including assent by legal guardian if under 18 years of age) and comply with the requirements of the protocol, including completion of the subject diary Exclusion Criteria: 1. Persons requiring or anticipated to require in-hospital care 2. Cystic fibrosis 3. Cardiac arrhythmia 4. Immunologic disorders or receiving immunosuppressive therapy (e.g., for organ or bone marrow transplants, immunomodulatory therapies for certain autoimmune diseases) 5. Untreated HIV infection or treated HIV infection with a CD4 count below 350 cells/mm3 in the last 6 months 6. Persons with sickle cell anemia or other hemoglobinopathies 7. Poorly controlled insulin-dependent diabetes mellitus (HbA1C \>8.0%) 8. Concurrent infection at the screening examination that requires systemic antimicrobial therapy 9. Females of childbearing potential who are either pregnant or sexually active without the use of birth control. Female subjects of child-bearing potential that are sexually active must have a negative baseline pregnancy test and must agree to continue an acceptable method of birth control for the duration of the study and for 1 month post-treatment. A double barrier method, oral birth control pills administered for at least 2 monthly cycles prior to study drug administration, an IUD, or medroxyprogesterone acetate administered intramuscularly for a minimum of one month prior to study drug administration are acceptable methods of birth control for inclusion into the study. Female subjects are considered of childbearing potential unless they are postmenopausal (absence of menstrual bleeding for 1 year - or 6 months if laboratory confirmation of hormonal status), or have had a hysterectomy, bilateral tubular ligation or bilateral oophorectomy. 10. Females who are breastfeeding 11. Receipt of any dose of NTZ within 30 days prior to screening 12. Prior treatment with any investigational drug therapy within 30 days prior to screening 13. Subjects with active respiratory allergies or subjects expected to require anti-allergy medications during the study period for respiratory allergies 14. Known sensitivity to NTZ or any of the excipients comprising the NTZ tablets 15. Subjects unable to take oral medications 16. Subjects who, in the judgment of the Investigator, will be unlikely to comply with the requirements of this protocol including completion of the subject diary