Investigation of pre-existing immunity to coronaviruses; implications for immunopathology and pathophysiology of COVID-19 disease

Background; It is unknown how prior exposure to commonly circulating human coronaviruses (HCoV) impacts immunity against highly-pathogenic species (SARS, SARS-CoV-2 & MERS). There are limited data, across Europe, Asia and Africa, on the prevalence of infection and seroconversion against widely circulating and mildly symptomatic HCoVs (229E, NL63, OC43, and HKU1). There is a current supposition that antibody-dependent-enhancement (ADE) may play a role in the pathophysiology of COVID-19. ADE occurs when non-neutralizing antiviral proteins facilitate virus entry into host cells, leading to increased infectivity in the cells. In such cases, higher viremia has been measured and the clinical course of disease can be more severe. In preclinical animal models, immunopathology was observed after challenge following vaccination with some SARS vaccines. Therefore, concerns have been raised regarding the impact of immunopathology and ADE on prophylactic vaccination against SARS and possibly SARS-CoV-2. Goals: to perform detailed systems serology of pre- existing immunity, in children and adults, from the UK and Africa, towards novel and commonly circulating coronaviruses. Impact: These studies highlight the limited knowledge in the field and a need for a systematic approach to investigate cross-reactive humoral immunity against HCoV to inform the immunopathology and pathophysiology of COVID-19.