Pan-ebolavirus serology study of healthcare workers in the Mbandaka Health Region, Democratic Republic of the Congo

Abstract

Although multiple antigenically distinct ebolavirus species can cause human disease, previous serosurveys focused on only Zaire ebolavirus (EBOV). Thus, the extent of reactivity or exposure to other ebolaviruses, and which sociodemographic factors are linked to this seroreactivity, are unclear. We conducted a serosurvey of 539 healthcare workers (HCW) in Mbandaka, Democratic Republic of the Congo, using ELISA-based analysis of serum IgG against EBOV, Sudan ebolavirus (SUDV) and Bundibugyo ebolavirus (BDBV) glycoproteins (GP). We compared seroreactivity to risk factors for viral exposure using univariate and multivariable logistic regression. Seroreactivity against different GPs ranged from 2.2–4.6%. Samples from six individuals reacted to all three species of ebolavirus and 27 samples showed a species-specific IgG response. We find that community health volunteers are more likely to be seroreactive against each antigen than nurses, and in general, that HCWs with indirect patient contact have higher anti-EBOV GP IgG levels than those with direct contact. Seroreactivity against ebolavirus GP may be associated with positions that offer less occupational training and access to PPE. Those individuals with broadly reactive responses may have had multiple ebolavirus exposures or developed cross-reactive antibodies. In contrast, those individuals with species-specific BDBV or SUDV GP seroreactivity may have been exposed to an ebolavirus not previously known to circulate in the region.

Low seroprevalence of Ebola virus in health care providers in an endemic region (Tshuapa province) of the Democratic Republic of the Congo

“…Indeed, EBOV infections may remain asymptomatic or paucisymptomatic after exposure to the pathogen [17]. This has been observed in recent studies where EBOV antigen seroreactivity is increasingly reported [8, 18, 19]. In unaffected areas, seroreactivity to EBOV-GP was reported in urban areas of Cameroon (1.3%), and DRC in Kinshasa (2%) and Kasaï Oriental (3.5%) [8, 18, 20, 21].…”

Molecular adaptations during viral epidemics

“…The dominant variants, as of June 2022, are all descendants of the Omicron variant, which first emerged in Fall 2021 and can be robustly classified into at least three sub‐lineages, BA.1, BA.2, and BA.3 (World Health Organization, 2021). Omicron sequences differ substantially from earlier variants and the human immune response to Omicron variant infection is measurably different (Sigal, 2022; Suryawanshi et al , 2022), further emphasizing the possibility that SARS‐CoV‐2 might evolve into regional subtypes (Rochman et al , 2021c) and eventually diverge into distinct serotypes with minimal cross‐protection (Shaffer et al , 2022).…”

“…Furthermore, sustained infection within an immune‐privileged environment (a “low‐dose” antibody regime) promotes antibody and vaccine escape (Rochman et al , 2021b). Although persistent infections display a reduced evolutionary rate relative to acute infections, perhaps impacted by variable tissue tropism (Blackley et al , 2016), the existence of these persistent viral niches within human hosts represents an evolutionary risk for the emergence of Ebola with epidemic potential as Ebola continues, at the time of writing, to circulate in the human population (Shaffer et al , 2022).…”

Epitope-focused immunogen design based on the ebolavirus glycoprotein HR2-MPER region

“…However, only few of the identified epitopes evoke antibody responses that recognize all three human pathogenic ebolaviruses, although many serological studies have shown occurrence of cross-reactivity at least for EBOV, BDBV and SUDV. [ 11 , 12 ] These epitopes include at least two non-overlapping internal fusion loop epitopes, the GP1-core, the GP1-2 interface, and the HR2-MPER epitope. In contrast, many other epitopes are virus-specific, such as those in the glycan cap and mucin-like domain [ 6 , 12 , 13 ].…”