THURSDAY, April 7 (HealthDay News) -- A new vaccine against yellow fever that contains inactivated yellow fever antigen shows promise as a safe alternative to live vaccine, according to research published in the April 7 issue of the New England Journal of Medicine.
Thomas P. Monath, M.D., from Xcellerex in Marlborough, Mass., and colleagues injected 60 healthy subjects with 0.48 μg or 4.8 μg of antigen on two occasions 21 days apart to test the safety and immunogenicity of XRX-001 vaccine.
The researchers found that 100 percent of the subjects receiving the higher of the two doses developed neutralizing antibodies, as did 88 percent of those receiving the lower dose. Antibody levels were significantly higher 10 days after the second injection in the 4.8 μg group than they were in the 0.48 μg group. Mild pain, tenderness and -- much less often -- itching at the injection site occurred more often in the vaccine groups than in those receiving placebo.
"A two-dose regimen of the XRX-001 vaccine, containing inactivated yellow fever antigen with an alum adjuvant, induced neutralizing antibodies in a high percentage of subjects. XRX-001 has the potential to be a safer alternative to live attenuated 17D vaccine," the authors write.
The study was funded by Xcellerex, the manufacturer of the study vaccine; several authors disclosed being employees of Xcellerex.