[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]
Vaccine. 2019 May 11. pii: S0264-410X(19)30622-X. doi: 10.1016/j.vaccine.2019.05.010. [Epub ahead of print]
Routine and pulse vaccination for Lassa virus could reduce high levels of endemic disease: A mathematical modelling study.
Davies J1, Lokuge K2, Glass K3.
Author information: 1 Medical School, Australian National University, Canberra, Australia. 2 Research School of Population Health, Australian National University, Canberra, Australia. 3 Research School of Population Health, Australian National University, Canberra, Australia. Electronic address: Kathryn.Glass@anu.edu.au.
Lassa fever is an acute viral illness caused by Lassa virus (LASV), a rodent-borne pathogen. LASV is endemic to much of Sub-Saharan West Africa, where seasonal outbreaks cause significant morbidity and mortality. Increased global awareness of LASV has led to development of improved diagnostic tests, treatments and vaccines. As vaccine candidates are trialled, it is essential to assess the potential outcomes of introducing a LASV vaccination program in endemic regions. This study investigates the potential outcomes of routine and pulse vaccination strategies using a deterministic mathematical model that captures seasonal LASV transmission between rodents and humans. For plausible parameter values, we find that immunization of 40% of infants at 70% vaccine effectiveness achieves a population-level reduction in infectious case numbers of 30%, while coverage of 60% at 90% vaccine effectiveness achieves a 56% reduction. Similar reductions can be achieved more rapidly via population-wide pulse vaccination at 11% coverage (30% reduction at 70% effectiveness) or 23% coverage (56% reduction at 90% effectiveness) repeated every 10 years. Similar pulse vaccine doses delivered at reduced frequency, but increased coverage achieves a greater reduction in infectious cases. Findings around infant vaccination are sensitive to our assumption that immunity is life-long, while pulse-vaccination has only slightly reduced effect if immunity lasts 10-30 years. An effective LASV vaccination program would incorporate pulse vaccination in addition to routine childhood immunization to limit disease. Estimates of feasible vaccine coverage and effectiveness are needed to fully quantify the likely benefits of a vaccination program in LASV endemic regions.
Copyright © 2019. Published by Elsevier Ltd.
KEYWORDS: Endemic transmission; Lassa virus; Mathematical model; Vaccine
PMID: 31088745 DOI: 10.1016/j.vaccine.2019.05.010
Keywords: Lassa fever; Vaccines; Mathematical models.