Inclusion Criteria:

Viral dynamics (primary outcome):

- The child must be less than 18 years of age

- Have a positive PCR sample for influenza, RSV or SARS-CoV-2,

- Have any one of the symptoms listed to meet testing eligibility: fever, cough,
shortness of breath, decreased or loss of taste or smell, muscle aches/joint pains
(unusual, long lasting, not related to injury), extreme tiredness (unusual fatigue
not otherwise explained), sore throat, runny or stuffy/congested nose, headache
(new, unusual, long-lasting), nausea/vomiting and/or diarrhea, and

- Be within 5 days of symptom onset

Household testing inclusion criteria (secondary outcome):

-Any individual in the same household (i.e. household contacts, defined as residing at
the same address) as the individual testing positive by PCR for influenza, RSV or
SARS-CoV-2

Classroom testing inclusion criteria (secondary outcome):

-Any individual in the same classroom (i.e. classroom contacts) as the individual testing
positive by PCR for influenza, RSV or SARS-CoV-2 (i.e. case identified through the THS
program)

Exclusion Criteria:

Viral dynamics (primary outcome):

-Participants will be ineligible if they are more than 5 days from symptom onset