• Vaccine Name: V-LSG + V-LSN
• Target Pathogen: Lassa Fever Virus
• Target Disease: Lassa fever
• Vaccine Ontology ID: VO_0004082
• Type: Vaccina virus
• Preparation: Each sequence is derived from the Josiah strain of Lassa virus, isolated from a patient in Sierra Leone (Fisher-Hoch et al., 2000).
• Virulence:
• Description: V-LSG is a vaccinia viruses expressing the S-segment Lassa glycoprotein and V-LSN is a vaccinia viruses expressing the S-segment Lassa nucleoprotein. V-LSG + V-LSN is a vaccine that includes injections of each V-LSG and V-LSN separately (Fisher-Hoch et al., 2000).

Monkey Response

• Host Strain: Rhesus and Cynomolgus
• Vaccination Protocol: All animals received a single vaccination consisting of 0.2 ml of vaccine given intradermally and simultaneously at four separate sites (each forearm and the lateral aspect of each thigh) at a dilution which delivered to each animal a total dose of 10^9 PFU. All animals were challenged subcutaneously with 10^3 to 10^4 PFU of the Josiah strain of Lassa virus in 0.5 ml of phosphate-buffered saline within 36 to 700 days (Fisher-Hoch et al., 2000).
• Persistence: The latest day on which virus could be recovered from serum was day 14, and that from tissues was day 21. Evidence for persistence elsewhere in tissues or fluids in survivors could not be found by cocultivation of tissues taken up to 112 days following challenge. However, autopsy and biopsy material examined by RT-PCR revealed that viral RNA could be detected at least 112 days after challenge (Fisher-Hoch et al., 2000).
• Side Effects: None noted
• Efficacy: When used together, V-LSG and V-LSN can provide sufficient means for protection against Lassa fever (Fisher-Hoch et al., 2000).
• Description: 5 out of 6 of the monkeys survived. This protection against death was significant when compared with the death rate of the controls. These animals showed significantly diminished mean virus titers compared with those of unvaccinated animals. The animal the died was the one with the longest vaccine-to-challenge interval. Survival diminished as the vaccine-to-challenge interval increased. A trend towards increasing duration of viremia was also observed with increased intervals between vaccination and challenge (Fisher-Hoch et al., 2000).