Table 1.

Live, attenuated replication competent RVFV vaccines in use or in development.

Vaccine	Derivation/Basis for attenuation	Marketing/Usage	Target indication	Adverse effects and other potential concerns	Evaluated for human use	Characteristics reducing risk of reassortment
Smithburn Neurotropic Strain (SNS)	Derived by empirical passage/ Not defined	Onderstepoort Biological Products (OBP) and (intermittently) other manufacturers (Egypt, Kenya)/50 years use in parts of Africa	Adult, (non-pregnant) ruminants	1.Low rates of abortions in sheep 2.inconsistent availability, vaccine quality and stability	No
Clone-13	Derived by empirical passage/ Internal deletion of 569 nucleotides in NSs	OBP/Africa since 2010	Ruminants	1.Single report of fetal malformations and stillbirths (experimental study only) 2.Experimental infection of mosquitoes	No	No detectable viremia (ruminants) below threshold for mosquito infection
MP-12	Derived by passage with chemical mutagenesis/ Multiple attenuating mutations in all 3 segments.	Zoetis/Conditionally licensed for use in U.S.	Ruminants, humans	1.Single report of abortion in sheep (experimental study) 2.Experimental transmission to mosquitoes	Phase I-II trials with promising results	Low viremia in ruminants and humans, below threshold for mosquito infection
MP-12-NSm-del	Derived by reverse genetics/ Deletion of NSm plus MP-12 attenuating mutations.	M.C.I Santé Animale/in development	Ruminants	None reported	No	No detectable viremia in ruminants. Not infectious for mosquitoes.
ΔNSs-ΔNSm rRVFV (DDVax™)	Derived by reverse genetics. Deletion of NSs and NSm	In development	Humans, ruminants	None reported	In development	No detectable viremia in ruminants. Not infectious for mosquitoes.
RVFV-4s	Derived by reverse genetics/ Split M segment, 4 segments, NSs deletion.	In development	Humans, Ruminants	None reported	In development	No detectable viremia in ruminants.