Development of a new vaccine for the prevention of Lassa fever.
BACKGROUND
Recent importation of Lassa fever into Germany, the Netherlands, the United Kingdom, and the United States by travelers on commercial airlines from Africa underscores the public health challenge of emerging viruses. Currently, there are no licensed vaccines for Lassa fever, and no experimental vaccine has completely protected nonhuman primates against a lethal challenge.


RESULTS
We developed a replication-competent vaccine against Lassa virus based on attenuated recombinant vesicular stomatitis virus vectors expressing the Lassa viral glycoprotein. A single intramuscular vaccination of the Lassa vaccine elicited a protective immune response in nonhuman primates against a lethal Lassa virus challenge. Vaccine shedding was not detected in the monkeys, and none of the animals developed fever or other symptoms of illness associated with vaccination. The Lassa vaccine induced strong humoral and cellular immune responses in the four vaccinated and challenged monkeys. Despite a transient Lassa viremia in vaccinated animals 7 d after challenge, the vaccinated animals showed no evidence of clinical disease. In contrast, the two control animals developed severe symptoms including rashes, facial edema, and elevated liver enzymes, and ultimately succumbed to the Lassa infection.


CONCLUSIONS
Our data suggest that the Lassa vaccine candidate based on recombinant vesicular stomatitis virus is safe and highly efficacious in a relevant animal model that faithfully reproduces human disease.
Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA. tom.geisbert@amedd.army.mil
Thomas W
TW
Geisbert
Steven
S
Jones
Elizabeth A
EA
Fritz
Amy C
AC
Shurtleff
Joan B
JB
Geisbert
Ryan
R
Liebscher
Allen
A
Grolla
Ute
U
Ströher
Lisa
L
Fernando
Kathleen M
KM
Daddario
Mary C
MC
Guttieri
Bianca R
BR
Mothé
Tom
T
Larsen
Lisa E
LE
Hensley
Peter B
PB
Jahrling
Heinz
H
Feldmann
D000818:Animals; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D007835:Lassa Fever / Q000276:immunology / Q000517:prevention & control*; D007836:Lassa virus / Q000276:immunology*; D008252:Macaca fascicularis; D014611:Vaccination; D014614:Vaccines, Synthetic; D014765:Viral Vaccines / Q000276:immunology; D014766:Viremia / Q000517:prevention & control
D014614:Vaccines, Synthetic; D014765:Viral Vaccines