Research as a pillar of Lassa fever emergency response: lessons from Nigeria

Olayinka, Adebola; Nwafor, Chioma Dan; Akano, Adejoke; Jan, Kamji; Ebhodaghe, Blessing Itohan; Elimian, Kelly Osezele; Ochu, Chinwe Lucia; Okwor, Tochi; Ipadeola, Oladipupo; Ukponu, Winifred; Okudo, Ifeanyi; Clement, Peter; Ilori, Elsie; Ihekweazu, Chikwe

doi:10.11604/pamj.2020.37.179.26425

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…This period covered the known peak season for Lassa incidence in Edo state and in Nigeria which runs from December to May particularly January to March. [3,28] Evidence suggest that in developing countries while over 70% of pregnant women may attend ANC at least once, only 20-40% deliver in a health facility. [29,30] Given this substantial risk of loss to follow up and coupled with the asymptomatic nature of Lassa fever; the sample size calculation was carried out based on a cross-sectional study design to detect seroprevalence at two time points (ANC and delivery).…”

Section: Study Population and Study Proceduresmentioning

confidence: 99%

Seroepidemiology of Lassa virus in pregnant women in Southern Nigeria: A prospective hospital-based cohort study

Kayem,

Okogbenin,

Okoeguale

et al. 2023

PLoS Negl Trop Dis

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Background There is limited epidemiological evidence on Lassa fever in pregnant women with acute gaps on prevalence, infection incidence, and risk factors. Such evidence would facilitate the design of therapeutic and vaccine trials and the design of control programs. Our study sought to address some of these gaps by estimating the seroprevalence and seroconversion risk of Lassa fever in pregnant women. Methodology/Principal findings We conducted a prospective hospital-based cohort between February and December 2019 in Edo State, Southern Nigeria, enrolling pregnant women at antenatal clinic and following them up at delivery. Samples were evaluated for IgG antibodies against Lassa virus. The study demonstrates a seroprevalence of Lassa IgG antibodies of 49.6% and a seroconversion risk of 20.8%. Seropositivity was strongly correlated with rodent exposure around homes with an attributable risk proportion of 35%. Seroreversion was also seen with a seroreversion risk of 13.4%. Conclusions/Significance Our study suggests that 50% of pregnant women were at risk of Lassa infection and that 35.0% of infections might be preventable by avoiding rodent exposure and conditions which facilitate infestation and the risk of human-rodent contact. While the evidence on rodent exposure is subjective and further studies are needed to provide a better understanding of the avenues of human-rodent interaction; public health measures to decrease the risk of rodent infestation and the risk of spill over events may be beneficial. With an estimated seroconversion risk of 20.8%, our study suggests an appreciable risk of contracting Lassa fever during pregnancy and while most of these seroconversions may not be new infections, given the high risk of adverse outcomes in pregnancy, it supports the need for preventative and therapeutic options against Lassa fever in pregnancy. The occurrence of seroreversion in our study suggests that the prevalence obtained in this, and other cohorts may be an underestimate of the actual proportion of women of childbearing age who present at pregnancy with prior LASV exposure. Additionally, the occurrence of both seroconversion and seroreversion in this cohort suggests that these parameters would need to be considered for the development of Lassa vaccine efficacy, effectiveness, and utility models.

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Section: Study Population and Study Proceduresmentioning

confidence: 99%

Seroepidemiology of Lassa virus in pregnant women in Southern Nigeria: A prospective hospital-based cohort study

Kayem,

Okogbenin,

Okoeguale

et al. 2023

PLoS Negl Trop Dis

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“…The response pillars in which the EOC was set up include coordination, case management, surveillance and epidemiology, infection, prevention and control, safe burial, turnaround time of laboratory test, risk communication and logistic pillars, research and vector control, food safety and environmental sanitation. 10 , 22 The research pillar was introduced to facilitate and support LF research that would provide evidence-based knowledge and inform appropriate preventive and control measures. Adequate funding would be required to support research and address important knowledge gaps that could aid in the management of LF outbreaks.…”

Section: Public Health Interventions For Lf In Nigeriamentioning

confidence: 99%

“…There are public health concerns about its incidence, virulence and potential as a bioterrorism agent. 7 – 11…”

Section: Introductionmentioning

confidence: 99%

“…There are public health concerns about its incidence, virulence and potential as a bioterrorism agent. [7][8][9][10][11] LF has an incubation period of 1 to 3 weeks, and this long incubation period means infected person resident on endemic regions can travel both locally and internationally thereby causing an epidemic. 4 The interconnection between West African countries and the ease of human movement escalates the risk of international spread of disease.…”

Section: Introductionmentioning

confidence: 99%

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Epidemiological trends of Lassa fever in Nigeria from 2015-2021: A review

Grace¹,

Egoh

Udensi

2021

Therapeutic Advances in Infection

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Introduction: Lassa fever is a viral haemorrhagic fever with non-specific symptoms that has shown an upward trend in Nigeria and other West African countries, which is depicted by high incidence and case fatality in recent years. There are different reports on the yearly case burden of Lassa fever from the Federal Ministry of Health in Nigeria, through the regulatory body – Nigeria Centre for Disease Control (NCDC). Being the epicentre of the disease, Lassa fever has been exported from Nigeria to both neighbouring and distant countries.Methods: The aim of this review was to carry out a retrospective analysis from January 2015 to 26 September 2021 of the weekly and yearly outbreak of Lassa fever in Nigeria based on selected publications. The focus was on timely diagnosis, treatment option, public health interventions and progress of clinical trials for vaccine candidates, and to identify proactive measures that can be sustained to curb periodic outbreaks. The review was done using percentages, cross-tabulation and graphical charts. Results: The predominant age group infected was 21 to 40 years with a male to female ratio of 1:0.8. A total of 3311 laboratory-confirmed Lassa fever cases out of 20,588 suspected cases were identified from 29 states. Edo, Ondo, Taraba, Ebonyi, Bauchi, Plateau and Nasarawa had yearly Lassa fever incidence over the time frame considered. Contact tracing was done on over 33,804 individuals with about 90% completing follow-up. Case fatality rate within the period ranged from 9.3% to 29.2%. There is a sharp decline in the epidemiological trend of Lassa fever in the yearly seasonal peaks from weeks 1 to 13 with about 75% reduction in incidence between 2020 and 2021. Conclusion: The effective management of Lassa fever needs the implementation of preventive methods, prompt laboratory diagnosis, timely treatment, provision of personal protective equipment, cross-border surveillance, contact tracing, community awareness and vector control in order to minimise spread.

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“…Research was introduced as a pillar to the existing EOC response pillars following the large LF outbreak in 2018. With the support of the WHO, the national LF research Plan was developed the same year, with the aim to identify, facilitate and support the conduct of research that would improve knowledge about LF and inform appropriate, evidence-based prevention, response, and control activities of the disease [ 18 ]. An example would be a study conducted from the 2019 response on investigating the factors associated with delayed presentation to healthcare facilities of LF cases [ 19 ].…”

Section: Multi Sectoral Response Using “One Health” Eoc Approachmentioning

confidence: 99%