Role of the Oral Microbiome & Mucosal Immunity in COVID-19 Disease

Inclusion Criteria: * • South Asian and White British persons and those diagnosed with symptomatic or asymptomatic COVID-19 infection. * Aged 18 or over. Able to understand and consent. * Uninfected subjects: no history of COVID-19; not vaccinated; (negative for anti-SARS-CoV2 nucleoprotein antibodies at lab) * For patient groups: Confirmed COVID-19 positivity, symptoms and symptom onset within the past 21 days; Be recently hospitalised with COVID-19 disease; Have COVID-19 disease proven by PCR testing for SARS-CoV-2 within the last 21 days; COVID disease severity graded as per NIH/WHO. * Recovered groups: Have had COVID-19 disease proven by PCR testing for SARS-CoV-2. COVID disease severity graded as per WHO or NIH equivalent criteria * Those willing to participate on a single occasion but unwilling to participate with longitudinal samples will not be excluded. * Smoking, obesity, diabetes, heart disease, antibiotics or treatment related to COVID is not excluded. Exclusion Criteria: * • Those patients unwilling to participate, those unable to understand sufficiently to give informed consent and those unable to participate due to the severity of COVID-19 disease. Those patients classified as not either South Asian or White British heritage. * Patients with malignancy, pregnancy, long term immune suppression, inability to give informed consent, not willing or able to have oral examination. * Diabetes not excluded but screening for diabetes will be performed: glucose will be assessed in blood/serum sample (150ul). Exclusion criteria summary: * Critically ill participants who cannot give informed consent * Those who are not willing to have an oral examination, or donate blood or saliva samples. * Those who cannot chew / drool to provide a SWMF sample due to severe/critical medical conditions * Participants with known malignancies or who are pregnant * Participants who are on long-term immunosuppressants (e.g. for autoimmune diseases) * Participation in other current research that is designed to, or is expected to alter the immune response. * Inability to communicate, understand or read English.