* not capable of giving informed consent * unable to self-administer the sinus rinses and mouth washes * unable to have healthcare professional-led swabs or self-administer the oral, nasal and/or nasopharyngeal swabs * unable to send swabs to the study team via the approved methods described in participant information leaflet and protocol * under 18 years of age. * known hypersensitivity to iodine * at risk of aspiration due to an unsafe swallow * hyperthyroidism or other manifest thyroid diseases * herpetiform dermatitis (duhring's disease) * planned or undergoing radioiodine treatment * actively breastfeeding * pregnant

* not capable of giving informed consent * unable to self-administer the sinus rinses and mouth washes * unable to have healthcare professional-led swabs or self-administer the oral, nasal and/or nasopharyngeal swabs * unable to send swabs to the study team via the approved methods described in participant information leaflet and protocol * under 18 years of age. * known hypersensitivity to iodine * at risk of aspiration due to an unsafe swallow * hyperthyroidism or other manifest thyroid diseases * herpetiform dermatitis (duhring's disease) * planned or undergoing radioiodine treatment * actively breastfeeding * pregnant

- not capable of giving informed consent - unable to self-administer the sinus rinses and mouth washes - unable to have healthcare professional-led swabs or self-administer the oral, nasal and/or nasopharyngeal swabs - unable to send swabs to the study team via the approved methods described in participant information leaflet and protocol - under 18 years of age. - known hypersensitivity to iodine - at risk of aspiration due to an unsafe swallow - hyperthyroidism or other manifest thyroid diseases - herpetiform dermatitis (duhring's disease) - planned or undergoing radioiodine treatment - actively breastfeeding - pregnant

- not capable of giving informed consent - unable to self-administer the sinus rinses and mouth washes - unable to have healthcare professional-led swabs or self-administer the oral, nasal and/or nasopharyngeal swabs - unable to send swabs to the study team via the approved methods described in participant information leaflet and protocol - under 18 years of age. - known hypersensitivity to iodine - at risk of aspiration due to an unsafe swallow - hyperthyroidism or other manifest thyroid diseases - herpetiform dermatitis (duhring's disease) - planned or undergoing radioiodine treatment - actively breastfeeding - pregnant