The live vaccine Smithburn strain requires only one dose and proved to confer immunity for 3 years but may cause abortion or birth defects if given to pregnant animals. The killed vaccines do not cause these effects but require two inoculations and annual revaccination to produce protective immunity. A live attenuated vaccine (MP-12) has shown to be safe and efficacious against virulent virus challenge and is safe in pregnant and neonatal livestock but is still under investigation.