Ebola exposure, illness experience, and Ebola antibody prevalence in international responders to the West African Ebola epidemic 2014–2016: A cross-sectional study

Abstract

BackgroundHealthcare and other front-line workers are at particular risk of infection with Ebola virus (EBOV). Despite the large-scale deployment of international responders, few cases of Ebola virus disease have been diagnosed in this group. Since asymptomatic or pauci-symptomatic infection has been described, it is plausible that infections have occurred in healthcare workers but have escaped being diagnosed. We aimed to assess the prevalence of asymptomatic or pauci-symptomatic infection, and of exposure events, among returned responders to the West African Ebola epidemic 2014–2016.Methods and findingsWe used snowball sampling to identify responders who had returned to the UK or Ireland, and used an online consent and questionnaire to determine their exposure to EBOV and their experience of illness. Oral fluid collection devices were sent and returned by post, and samples were tested using an EBOV IgG capture assay that detects IgG to Ebola glycoprotein. Blood was collected from returnees with reactive samples for further testing. Unexposed UK controls were also recruited.In all, 300 individuals consented, of whom 268 (89.3%) returned an oral fluid sample (OFS). The majority had worked in Sierra Leone in clinical, laboratory, research, and other roles. Fifty-three UK controls consented and provided samples using the same method.Of the returnees, 47 (17.5%) reported that they had had a possible EBOV exposure. Based on their free-text descriptions, using a published risk assessment method, we classified 43 (16%) as having had incidents with risk of Ebola transmission, including five intermediate-risk and one high-risk exposure. Of the returnees, 57 (21%) reported a febrile or diarrhoeal illness in West Africa or within 1 mo of return, of whom 40 (70%) were not tested at the time for EBOV infection.Of the 268 OFSs, 266 were unreactive. Two returnees, who did not experience an illness in West Africa or on return, had OFSs that were reactive on the EBOV IgG capture assay, with similar results on plasma. One individual had no further positive test results; the other had a positive result on a double-antigen bridging assay but not on a competitive assay or on an indirect EBOV IgG ELISA. All 53 controls had non-reactive OFSs. While the participants were not a random sample of returnees, the number participating was high.ConclusionsThis is the first study, to our knowledge, of the prevalence of EBOV infection in international responders. More than 99% had clear negative results. Sera from two individuals had discordant results on the different assays; both were negative on the competitive assay, suggesting that prior infection was unlikely. The finding that a significant proportion experienced “near miss” exposure events, and that most of those who experienced symptoms did not get tested for EBOV at the time, suggests a need to review and standardise protocols for the management of possible exposure to EBOV, and for the management of illness, across organisations that deploy staff to outbreaks.

A novel personal protective equipment coverall was rated higher than standard Ebola virus personal protective equipment in terms of comfort, mobility and perception of safety when tested by health care workers in Liberia and in a United States biocontainment unit

“…High risk was defined as definite exposure of mucous membranes or broken skin with the bodily fluids of a patient with EVD (eg, a needlestick injury through visibly soiled gloves). 3 Some HCWs became infected without a known exposure, raising further questions about the effectiveness of current PPE and PPE protocols. 4 The doffing process is believed to be a particularly high-risk time in terms of self-contamination and subsequent infection.…”

Serosurvey on healthcare personnel caring for patients with Ebola virus disease and Lassa virus in the United States

“…In this group of international responders returning from West Africa, 1 study participant appeared to have low-level reactivity that was not confirmed by other studies, and 1 study participant had reactivity that was not replicated on a different assay; all other providers (99%) tested negative. 20 As our study has demonstrated, HCP who received investigational EBOV vaccines may produce antibody responses against the EBOV proteins included in the vaccines. Some of our HCP had received EBOV vaccines expressing a single EBOV protein, GP.…”

<i>In silico</i> Characterization and Selection of Epitope-based Peptide Vaccines Against Ebola Viruses

“…In this study, we analyzed the Ebolavirus membrane proteins which are NP, VP35, VP40, sGP, ssGP, VP30, and VP24 proteins. And the prediction of antigenicity of the non-identical sequences from membrane proteins were done with VaxiJen server [23] and TMHMM [24] prediction address used to identify exo-membrane amino acid sequence of specific protein. Antigenic B-cell epitopes predictions were done using BCPred and AAP prediction methods.…”