To assess if TSLP expression by airway epithelial cells following COVID-19 infection regulates viral load and disease severity.

The study aim is to determine the relationship between COVID-19 infection and epithelial cell expression of TSLP. Two cohorts will be used. Cohort One will include 100 hospitalized patients with Covid-19, and 100 hospitalized patients without Covid-19. Cohort 2 will include mild/moderate asthmatics and healthy controls with bio-banked biopsy material used from donors who have previously consented for samples to be used for future research.

Inclusion Criteria:

• Age 18 years and above;
• Able to give informed consent;
• Clinically tested for SARS-CoV-2 (as completed by standard laboratory testing e.g. RT-PCR) and with a positive result and clinical features in keeping with COVID-19 illness. The control group will be patients with a negative RT-PCR COVID-19 test and without any clinical features to suggest COVID-19 illness. In addition, the control group should have NO known or current features of respiratory infection, COPD, asthma, interstitial lung disease, other respiratory inflammatory conditions or lung cancer.
• Able to provide a breath sample (as based on clinical judgement).

Exclusion Criteria:

- none

Hospitalized patients