Among the key findings, which have not yet been peer-reviewed, are:
- Individuals who have asymptomatic or mild disease show a robust immune response early on during infection.
- Patients requiring admission to hospital have impaired immune responses and systemic inflammation (that is, chronic inflammation that may affect several organs) from the time of symptom onset.
- Persistent abnormalities in immune cells and a change in the body’s inflammatory response may contribute to ‘long COVID’.
The immune response associated with COVID-19 is complex. Most people who get infected by SARS-CoV-2 mount a successful antiviral response, resulting in few if any symptoms. In a minority of patients, however, there is evidence that the immune system over-reacts, leading to a flood of immune cells (a ‘cytokine storm’) and to chronic inflammation and damage to multiple organs, often resulting in death.
To better understand the relationship between the immune response and COVID-19 symptoms, scientists at the University of Cambridge and Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust, have been recruiting individuals who test positive for SARS-CoV-2 to the COVID-19 cohort of the NIHR BioResource. These individuals range from asymptomatic healthcare workers in whom the virus was detected on routine screening, through to patients requiring assisted ventilation. The team take blood samples from patients over several months, as well as continuing to measure their symptoms.
In research published this week, the team analysed samples from 207 COVID-19 patients with a range of disease severities taken at regular interviews over three months following the onset of symptoms. They compared the samples against those taken from 45 healthy controls.
Because of the urgent need to share information relating to the pandemic, the researchers have published their report on MedRXiv. It has not yet been peer-reviewed.
Image: SARS-CoV-2 virus particles are shown emerging from the surface of cells cultured in the lab
Credit: NIH Image Gallery
Reproduced courtesy of the University of Cambridge