Absolute proportion of patients in each arm meeting the threshold of 20.2% neutralising antibody required for clinical protection from SARS-CoV2 infection. Neutralising antibody titres will be assessed by dilution at which paCoV-2 live virus entry into angiotensin converting enzyme (ACE) 2 receptor positive cells by 50%.[4-6 weeks post-vaccination. During the intervening post-vaccination period patients will be clinically assessed once by phone 1 week post vaccination. ]

Absolute proportion of patients in each arm meeting the threshold of 20.2% neutralising antibody required for clinical protection from SARS-CoV2 infection. Neutralising antibody titres will be assessed by dilution at which paCoV-2 live virus entry into angiotensin converting enzyme (ACE) 2 receptor positive cells by 50%.[4-6 weeks post-vaccination. During the intervening post-vaccination period patients will be clinically assessed once by phone 1 week post vaccination. ]