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

Author summaryZaire ebolavirus is known to circulate in the Mbandaka region of the Democratic Republic of the Congo, causing outbreaks in 2018 and 2020. However, we do not know the range of exposure to the local population. Here, we examined the seroprevalence of 539 local Congolese healthcare workers in the Mbandaka region with no known ebolavirus exposure. We found serological evidence indicating contact with at least one species of ebolavirus from these donors. Seroreactivity among the donors to the different glycoprotein antigens ranged between 2.2-4.6%. We observed correlations between jobs with indirect access to patients and a higher seroprevalence, which may be due to less training and less access to personal protective equipment. Our findings suggest that exposure to ebolaviruses may be more frequent than previously known and that lesser-skilled individuals in healthcare work may have a higher likelihood of ebolavirus exposure. 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.