The Recurrent Outbreaks Of Ebola In Africa: Bibliometric Analysis,Systematic Review And Meta-analysis

Background:Within the past decade,Africa has faced several recurrent outbreaks of Ebola Virus Disease（EVD）,including the 2014-2016 outbreak in West Africa,and the ongoing2018-2020 Kivu outbreak in the Democratic Republic of Congo.These outbreaks have presented with varying case fatality rates（CFR）and other socio-economic impacts.Despite the recurrent outbreaks of EVD in Africa,less has been documented about the risk and impact of the disease among specific vulnerable groups like pregnant women and children.Objective:The study aimed to quantify and map the scientific output of EVD research published within 2010-2019 though a Bibliometric perspective,in addition to summarising the impact of EVD（Case fatality rate and perinatal outcomes）among pregnant women and the general population in Africa within the past ten years.Methods:Bibliometric analysis-Ebola-related publications from 2010 to 2019 were retrieved from the Web of Science（Wo S）database by using the keywords“Ebola”,“Ebola Virus Disease”,“Ebolas”,and“ebolavirus”.Hist Cite and Biblioshiny software were used to categorise and evaluate authors,countries and journals contribution.VOSviewer was used for network visualisation.Systematic review and Meta-analysis of EVD studies published from 1^st January 2010,through 25^th March 2020 was conducted using Wo S,Scopus and Pub Med databases.English articles and reports,including the number of cases and deaths during the outbreak in Africa,were considered for meta-analysis.Besides,studies that reported atleast one of birth outcome related to EVD were included in the review of EVD in pregnancy.The analysis was conducted using Stata（version 12）,pooled effect sizes were calculated using the random-effects model and heterogeneity was tested for using the I² statistic.Results:Bibliometric analysis-A total of 4884 EVD-related documents were published within the study period in Wo S according to the search strategy.Almost a half（49.2%）of the papers were research articles,and the average citations per document were 11.55.The results show an overall increase in publication trend within the study period.The leading countries in ebola research were the USA（46.4%）,England（13.8%）and Canada（7.2%）,including Sierra Leone（6.5%）and Liberia（3.9%）.National Institute of Allergy&Infectious Diseases-NIAID（253）was the most influential institution,while“Infectious Diseases”（1027）was the most decisive research field.The most contributing authors included Feldmann H（99）,Qiu XG（68）,and Kobinger GP（56）,and“Journal of Infectious diseases”was the most crucial journal.The most cited article was from Aylward B et al.published in 2014,while 2018displayed a keyword focus on“double-blind”,“Safety”and“trial”.Regarding the meta-analysis,13 studies with 32,300 cases and 13,727 deaths were identified whose pooled CFR was 60%（95%CI:47-73%）.The most EVD-affected countries were DRC with 5 outbreaks and a pooled CFR of 65%（95%CI:59-71%）,followed by Uganda with 3 outbreaks and CFR=83%（95%CI:60-99%）.Zaire ebolavirus caused the most outbreaks（10）,with a CFR=58%（95%CI:44-71%）.Besides,outbreaks with less than 1000cases reported a higher CFR rate compared to those with more cases.From the reviewed studies,a total of 96 EVD-infected pregnant women were reported,with a considerably high maternal mortality（67.8%）,and with severe fetal outcomes and rare chances of neonatal survival even with live or normal delivery.Stillbirths（42.5%）and spontaneous abortions（38.3%）were the most reported fetal outcomes,including preterm birth.Conclusions:The bibliometric analysis provides an updated historical perspective of progress in EVD research and has highlighted the leading role played by various stakeholders.The study has revealed a considerably high CFR caused by the recurrent EVD outbreaks in Africa.It also notes an implementation gap of the prevention and control strategies,and so identifies a need to strengthen the surveillance systems and response mechanisms to enable early detection and prompt control of future outbreaks.Besides,the study has also noted considerably high maternal mortality attributed to EVD in pregnancy,with severe fetal outcomes and rare chances of neonatal survival.This indicates a need for targeted interventions and special consideration of pregnant women to prevent infection and alleviate the adverse maternal and perinatal outcomes attributed to EVD.