From the article: The Ebola virus has five known subtypes, the most common of which are Ebola-Zaire, the one that caused the West African outbreak, and Ebola-S

From the article: The Ebola virus has five known subtypes, the most common of which are Ebola-Zaire, the one that caused the West African outbreak, and Ebola-Sudan. Ebola is also related to Marburg virus, which is similarly lethal. An ideal vaccine would protect against all Ebola strains and Marburg. However, Dr. Kieny said, it may not be possible to make a shot effective against several strains if it is based on the VSV spine because VSV triggers a lot of side effects.