In depth analysis of patients with severe SARS-CoV-2 in sub-Saharan Africa demonstrates distinct clinical and immunological profiles

Abstract

Understanding the host viral interaction at the nasal mucosa, the primary site of SARSCoV2 infection, may provide important insights into COVID19 pathogenesis. Here, we studied nasal and systemic immune parameters in comprehensively characterised patients hospitalised with suspected or confirmed COVID19, and healthy community controls. PCR confirmed COVID19 participants were more likely to receive dexamethasone and a betalactam antibiotic, and more likely to survive to hospital discharge than PCR negative/IgG+ and PCR negative/IgG- participants. PCR negative/IgG+ participants exhibited a nasal and systemic cytokine signature analogous to PCR confirmed COVID19 participants, but had an increased propensity for Staphylococcus aureus and Streptococcus pneumoniae colonisation. The nasal immune signature in PCR negative/IgG+ and PCR confirmed COVID19 participants was distinct and predominated by chemokines and neutrophils. These findings demonstrate that severe COVID19 is associated with inflammatory chemokine and neutrophil predominance in the nasal mucosa, and that PCR negative/IgG+ individuals with high COVID19 clinical suspicion have inflammatory profiles analogous to PCR confirmed disease.

High seroprevalence of anti-SARS-CoV-2 antibodies in the capital of Chad

“…Several hypotheses have been put forward to understand this African paradox, 8,12,13 and immunological assessments of SARS-CoV-2 circulation in the African population were performed after the different waves of the pandemic. 14,15 Although sub-Saharan Africa reports a low rate of COVID-19 as well as low mortality, some studies have shown that overall anti-SARS-CoV-2 seroprevalence could be high. 14,16−18 These studies prove that a significant proportion of the population in this part of the African continent has been in contact with this virus.…”

Proteomic Analysis of Mucosal and Systemic Responses to SARS-CoV-2 Antigen

“…Since the declaration by the WHO on 30 January 2020 of SARS-CoV-2 as a public health emergency of international concern [ 1 ], a broad range of clinical outcomes following exposure to the virus have been observed, from asymptomatic to mild non-specific syndromes, to acute respiratory distress syndrome [ 2 ]. However, a limited number of studies have evaluated the potential for proteomic biomarkers of risk or protection other than antibody levels in the human mucosal portal of viral entry, the upper respiratory tract [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Furthermore, despite the rapid approval and roll-out of multiple vaccine strategies [ 11 ], which have been key to reducing the number of fatalities, limited knowledge is available on the potential mucosal markers of protection elicited by vaccination, including antibody levels in the nasal and oral cavity, as well as other vaccine-modulated mucosal factors which could affect the susceptibility of these portals of entry to SARS-CoV-2 infection.…”