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Ebola vaccination

2015; Elsevier BV; Volume: 386; Issue: 10012 Linguagem: Inglês

10.1016/s0140-6736(15)01244-1

1474-547X

Sarah Tschudin‐Sutter, Andreas F. Widmer, Petra Emmerich, Jonas Schmidt‐Chanasit, Manuel Battegay,

Vaccine Coverage and Hesitancy

In 1994, a 34-year-old female ethologist was diagnosed with Ebola virus disease after completing an autopsy on a wild chimpanzee.1Le Guenno B Formenty P Wyers M Gounon P Walker F Boesch C Isolation and partial characterisation of a new strain of Ebola virus.Lancet. 1995; 345: 1271-1274Summary PubMed Scopus (136) Google Scholar Laboratory investigations led to the isolation of a new species of Ebola virus, Taï Forest Ebolavirus, named after its place of origin. Before the emergence of Zaire Ebolavirus in west Africa, this case was the first documentation of Ebola virus disease in the region and the only reported case of Ebola virus disease caused by Taï Forest Ebolavirus to date.1Le Guenno B Formenty P Wyers M Gounon P Walker F Boesch C Isolation and partial characterisation of a new strain of Ebola virus.Lancet. 1995; 345: 1271-1274Summary PubMed Scopus (136) Google Scholar Increasing titres of IgM antibody against Taï Forest Ebolavirus were detected in blood samples drawn from this patient on days 3 and 7 after symptom onset, and IgG antibodies were noted in the next available sample drawn 16 days later (figure).1Le Guenno B Formenty P Wyers M Gounon P Walker F Boesch C Isolation and partial characterisation of a new strain of Ebola virus.Lancet. 1995; 345: 1271-1274Summary PubMed Scopus (136) Google Scholar Although IgM antibodies reacted only with the Taï Forest Ebolavirus antigen, the IgG antibodies showed cross-reactivity to the Zaire Ebolavirus, Sudan Ebolavirus, and Reston Ebolavirus antigens; the most cross-reactive of which seemed to be the Zaire Ebolavirus antigen.1Le Guenno B Formenty P Wyers M Gounon P Walker F Boesch C Isolation and partial characterisation of a new strain of Ebola virus.Lancet. 1995; 345: 1271-1274Summary PubMed Scopus (136) Google Scholar The patient fully recovered after 6 weeks2Formenty P Hatz C Le Guenno B Stoll A Rogenmoser P Widmer A Human infection due to Ebola virus, subtype Cote d'Ivoire: clinical and biologic presentation.J Infect Dis. 1999; 179: S48-S53Crossref PubMed Scopus (206) Google Scholar and follow-up blood samples showed peaking IgG antibody concentrations on day 40 and persistence on day 466 after disease onset (figure).1Le Guenno B Formenty P Wyers M Gounon P Walker F Boesch C Isolation and partial characterisation of a new strain of Ebola virus.Lancet. 1995; 345: 1271-1274Summary PubMed Scopus (136) Google Scholar, 2Formenty P Hatz C Le Guenno B Stoll A Rogenmoser P Widmer A Human infection due to Ebola virus, subtype Cote d'Ivoire: clinical and biologic presentation.J Infect Dis. 1999; 179: S48-S53Crossref PubMed Scopus (206) Google Scholar On July 14, 2015 (7534 days after onset of symptoms), IgG antibody titres against Taï Forest Ebolavirus, Zaire Ebolavirus, and Sudan Ebolavirus antigens were still detectable at titres of 1/160 in an indirect immunofluorescence assay (IIFA) for all three species. This assay was implemented with Taï Forest Ebolavirus, Zaire Ebolavirus, and Sudan Ebolavirus infected Vero E6 cells as described elsewhere.3Kreuels B Wichmann D Emmerich P et al.A case of severe Ebola virus infection complicated by gram-negative septicemia.N Engl J Med. 2014; 371: 2394-2401Crossref PubMed Scopus (233) Google Scholar Little is known about whether humoral immunity after Ebola virus disease is long lasting. IgG antibody responses were reported in 20 survivors of three different Zaire Ebolavirus outbreaks in Gabon (ie, in Mayibout 1996, Booué 1996, and Mekambo 2001) after up to 11 years of follow-up.4Wauquier N Becquart P Gasquet C Leroy EM Immunoglobulin G in Ebola outbreak survivors, Gabon.Emerg Infect Dis. 2009; 15: 1136-1137Crossref PubMed Scopus (45) Google Scholar Although these studies into antibody responses in survivors of Ebola virus disease suggest the importance of antibody concentrations regarding immunity, confirmatory studies are scarce. The interim results by Ana Maria Henao-Restrepo5Henao-Restrepo AM Longini IM Egger M et al.Efficacy and effectiveness of an rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomised trial.Lancet. 2015; 386: 857-866Summary Full Text Full Text PDF PubMed Scopus (573) Google Scholar on the efficacy and effectiveness of the recombinant, replication-competent vesicular stomatitis virus-based vaccine expressing a surface glycoprotein of Zaire Ebolavirus showed no new cases of infection in the immediate vaccination group, supporting the importance of the humoral immune response. Our report adds to the growing body of evidence that IgG antibody responses are sustainable and cross-reactive in survivors of Ebola virus disease. These findings underscore the usefulness of serological assays to investigate the complex epidemiological pattern of Ebolavirus in humans while possibly disguising the distribution of different species. The effectiveness of detectable IgG concentrations after natural infection or vaccination in providing ongoing and cross-immunity to different Ebolavirus strains remains to be determined. AFW is a board member of Swissnoso and received personal fees for consultancy and lectures, and grants from Astellas and the Commission for Technology and Innovation of the Swiss Government, outside the submitted work. MB received grants from Janssen, Merck, and Abbvie, and received personal fees from Roche, outside the submitted work. All other authors declare no competing interests. Efficacy and effectiveness of an rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomised trialThe results of this interim analysis indicate that rVSV-ZEBOV might be highly efficacious and safe in preventing Ebola virus disease, and is most likely effective at the population level when delivered during an Ebola virus disease outbreak via a ring vaccination strategy. Full-Text PDF Ebola vaccination – Authors' replyIn his linked Comment1 about the interim results of the Ebola ça suffit trial,2–4 Philip Krause makes several important points. 90 clusters were included in the planned interim analysis of this cluster randomised trial: 48 clusters were assigned to immediate vaccination with the rVSV-ZEBOV Ebola vaccine and 42 clusters were assigned to delayed vaccination with rVSV-ZEBOV. In the immediate vaccination group, no cases of Ebola virus disease were noted with symptom onset at least 10 days after randomisation, whereas in the delayed vaccination group there were 16 cases from seven clusters. Full-Text PDF