In December 2019, a cluster of patients with pneumonia of unknown aetiology was linked to an
infection with a novel coronavirus - the SARS-CoV-2. Since then, the infection has become
pandemic and spread affecting almost every country in the world. Knowledge of virus dynamics
and the host's immune response to it is essential to understanding the pathogenesis as well
as in formulating diagnostic, therapeutic and preventive strategies. There are no studies,
however, related to these issues, particularly in Sub-Saharan Africa (SSA) context. Previous
studies by the investigators have shown that the immune profile of healthy Ethiopians shows
evidence of chronic immune activation with significant low naïve cells but high activated
memory cells, of both CD4+ and CD8+ T-cell sub populations. The above immune system
characteristics of Ethiopians as compared to Europeans led the investigators to the
assumption that these could contribute to the pathogenesis of and severity of clinical
presentation of COVID-19. Persistent immune activation due to continuous infections with
helminths is common in the entire SSA region. Such activation usually skewes the immune
system towards T helper (Th)-2-type responses. The immune response against SARS-CoV-2 is
typically of so called "cytokine storm". Here, the investigators hypothesize that SARS-CoV-2
infection induced immune activation as observed in patients in the industrialized world (with
concomitant cytokine storms and extensive non-specific CD8 T-cell cytotoxicity) might be more
prominent than in people from SSA, due to the Th2 profile of their immune system.

The investigators propose to study the profile of the immune response of Ethiopian population
and will examine its relationship with the noted low CD4+ T-cell count and underlying immune
activation status among patients with COVID-19 and will compare results with those residing
in Europe. In addition, this project will evaluate the performance of various rapid
diagnostic tests (RDTs) for SARS-CoV-2, taking into account the above-determined immune
system characteristics. In addition, the investigators will evaluate the RDTs for use in the
screening of infected patients who are asymptomatic, in particular in health-care settings,
as well as for monitoring recovery or clearance of virus shedding for use in
resource-constrained setting. Such comparative studies will help identify immune factors that
could play a role in attenuating the disrupted immune responses caused by SARS-CoV-2
infection and thus contribute to the design and development of effective diagnostic,
therapeutic or vaccine.

The pathogenesis of severe COVID-19 is related to hyper-inflammation. However, COVID-19
symptomatology in SSA appears significantly less serious than in industrialized world. We
postulate that individuals residing in SSA and co-infected with intestinal parasites down
regulate immune to SARS-CoV-2 and mute COVID-19 severity.