Inclusion criteria | Exclusion criteria | |||
---|---|---|---|---|
Hospitalised | Community-symptomatic | Community-recovered | Comparison | All groups |
Currently serving UK Military Personnel at time of recruitment | Currently serving UK Military Personnel at time of recruitment | Currently serving UK Military Personnel at time of recruitment | Currently serving UK Military Personnel at time of recruitment | Unwilling or unable to give informed consent |
Previous COVID-19 infection—requiring hospital admission | Previous COVID-19 infection—self-limiting mild/moderate acute illness, not requiring hospital admission | Previous COVID-19 infection- self-limiting mild/moderate acute illness, not requiring hospital admission | No previous clinical suspicion of acute COVID-19 infection | Past medical history of cardiac or pulmonary disease (excluding mild asthma and controlled hypertension) |
Positive COVID-19 antigen PCR test at time of acute illness, or clinically adjudicated COVID-19 | Positive COVID-19 antigen PCR test at time of acute illness, or clinically adjudicated COVID-19 | Positive COVID-19 antigen PCR test at time of acute illness, or clinically adjudicated COVID-19 | Negative COVID-19 antibody test at recruitment to study | Active acute infection at the time of recruitment as determined by clinical assessment |
Negative for COVID-19 antigen PCR test at recruitment to study | Negative for COVID-19 antigen PCR test at recruitment to study | Negative for COVID-19 antigen PCR test at recruitment to study | Negative for COVID-19 antigen PCR test at recruitment to study | Unable to meet the criteria of the MRI safety questionnaire |
 > 4 weeks since resolution of fever/acute illness |  > 4 weeks since resolution of fever/acute illness |  > 4 weeks since resolution of fever/acute illness | – | Pregnant at the time of recruitment to the study |
– | Ongoing post-acute symptoms/exercise intolerance | No ongoing post-acute symptoms/exercise intolerance | – | Unable, or unwilling, to complete any research investigations |