Please select the eligibility criteria that correspond to the clinical trial below.
Title: McFlu2 COLD3 Prevention: A Randomized, Placebo-controlled, Double Blind Trial of Vitamin D and Health Advice for the Prevention of Upper Respiratory Tract Infections in McMaster University Students
Brief Summary: The specific objectives of this investigation are to assess the effectiveness of daily gargling and vitamin D supplementation as preventative measures against incident upper respiratory tract infection (URTI) in students attending McMaster University. Investigators hypothesize that

1. Vitamin D3 supplementation will decrease the incidence of symptomatic upper respiratory tract infections in university students
2. Gargling will decrease the incidence of symptomatic upper respiratory tract infections in university students.


Options:
A: Inclusion Criteria:

* Current or part-time student at McMaster University
* 17 year of age or older
* Currently living:

  i. In residence or, ii. Off-campus with at least one student housemate
* Willing and able to sign an informed consent

Exclusion Criteria:

* Students who do not meet the inclusion criteria
* Currently living at home with parents
* History or diagnosis of hypercalcemia
* Diagnosis of parathyroid disorder (hyper or hypo)
* Diagnosis of chronic kidney disease
* Use of anticonvulsants
* Malabsorption syndromes
* Diagnosis of sarcoidosis
* Currently pregnant or planning a pregnancy
* Inability to swallow capsules
B: Inclusion Criteria:

* Older than 18 years of age and without symptoms associated with corona-virus (or previously tested positive for corona).
* Participant is outside their home more than 3 hours a day. E.g.for work or for other activities among other people.
* Do not normally wear a facial mask for daily work (e.g. healthcare personnel)

Exclusion Criteria:

* Previously tested positive for corona-virus
* Wear facial mask for work
C: Inclusion Criteria:

* Clinical site leadership has agreed to have one or more staff participate in the trial
* Subject meets the definition of "healthcare personnel"
* Subject able to read and sign informed consent
* Subject agrees to all requirements of the protocol, including fit testing and diary keeping
* Subject's age is 18 or greater
* Subject passes fit testing for one of the study supplied respirator models and agrees to use that model for the entire intervention period of the study (if in respirator arm).

Exclusion Criteria:

* Subject self-identified as having severe heart, lung, neurological or other systemic disease that one or more Investigator believes could preclude safe participation
* Known to not tolerate wearing respiratory protective equipment for any period
* Facial hair, or other issue such as facial adornments, precluding respirator OSHA-compliant fit testing or proper mask fit during the study period
* Advised by Occupational Health (or other qualified clinician) to not wear the same or similar respirator or medical mask models used in this study
* In the opinion of the Investigator, may not be able to reasonably participate in the trial for any reason
* Self-identified as in, or will be in the third trimester of pregnancy, during the study period.
* Subject rotating in 2 different ResPECT study clinic sites /clusters during the 12-week study period.
* Subject works less than 75% of the intervention period in that clinic.
* Subject is a previous participant of the ResPECT Study, but does not consent for data from previous flu season(s) to be linked.
D: Inclusion Criteria:

* Trainees assigned to one of the six selected training battalions
* Trainees who present with an SSTI at the clinic or the hospital
* Provide informed consent

Exclusion Criteria:

* Fails to meet inclusion criteria

Answer: A