Subjects are eligible to be included in the study only if all of the criteria below apply. 1. Ability to understand the purpose and risks of the study and provide signed and dated informed consent or have a legal representative provide consent and authorization to use protected health information (in accordance with national and local patient privacy regulations). Clinical Study Protocol - 3.0 AstraZeneca Acalabrutinib - ACE-ID-201 (D822FC00001) CONFIDENTIAL AND PROPRIETARY 26 of 88 2. Men and women &#8805,18 years of age at the time of signing the Informed Consent Form (ICF). 3. SARS-CoV-2 confirmed per World Health Organization (WHO) criteria (including positive nucleic acid test of any specimen [eg, respiratory, blood, urine, stool, or other bodily fluid]) within 4 days of randomization. 4. COVID-19 pneumonia (documented radiographically) requiring hospitalization and oxygen saturation <94% on room air or requires supplemental oxygen. 5. Able to swallow pills. 6. Willing to follow contraception guidelines (refer to Appendix F).

Subjects are eligible to be included in the study only if all of the criteria below apply. 1. Ability to understand the purpose and risks of the study and provide signed and dated informed consent or have a legal representative provide consent and authorization to use protected health information (in accordance with national and local patient privacy regulations). Clinical Study Protocol - 3.0 AstraZeneca Acalabrutinib - ACE-ID-201 (D822FC00001) CONFIDENTIAL AND PROPRIETARY 26 of 88 2. Men and women &#8805,18 years of age at the time of signing the Informed Consent Form (ICF). 3. SARS-CoV-2 confirmed per World Health Organization (WHO) criteria (including positive nucleic acid test of any specimen [eg, respiratory, blood, urine, stool, or other bodily fluid]) within 4 days of randomization. 4. COVID-19 pneumonia (documented radiographically) requiring hospitalization and oxygen saturation <94% on room air or requires supplemental oxygen. 5. Able to swallow pills. 6. Willing to follow contraception guidelines (refer to Appendix F).