This meta-trial is a prospective collaborative individual participant data meta-analysis of randomised controlled trials and early phase studies. Individual studies will be conducted in multiple countries, including Australia, the UK, the USA, Ireland, Argentina, Brazil and Egypt.

Adult patients admitted to the hospital with confirmed SARS-CoV-2 infection, who do not require immediate mechanical ventilation, will be randomised to inhaled nebulised heparin or standard care for up to 21 days or until the patient has no respiratory symptoms. All studies will collect a minimum core dataset. The primary outcome for the meta-trial is the proportion of patients who receive invasive mechanical ventilation censored at day 28. Individual studies may have specific outcome measures in addition to the core set.

Inclusion Criteria:

• Patients admitted to hospital with COVID-19
• No immediate requirement for mechanical ventilation (points 3-5 on the WHO ordinal scale)
• Age equal to or greater than 18
• Able to provide informed consent

Exclusion Criteria:

• Pregnant women
• Known allergy to Heparin
• Participant in another clinical trial that is not approved for joint enrollment.
• APTT> 120 seconds, not due to anticoagulant therapy.
• Platelet count <20 x 109 per L
• Lung bleeding.
• Uncontrolled bleeding
• Advanced neurological impairment
• Advanced oncological disease

This meta-trial is a prospective collaborative individual participant data meta-analysis of randomised controlled trials and early phase studies.