HealthDay News — Chimpanzee adenovirus-vectored respiratory syncytial virus (PanAd3-RSV) vaccine candidate and a modified vaccinia Ankara (MBA-RSV) vaccine show potential for human RSV (HRSV), according to two studies published in Science Translational Medicine.
Geraldine Taylor, PhD, from The Pirbright Institute in Woking, U.K., and colleagues examined the safety and efficacy of the PanAd3-RSV vaccine using the calf model of bovine RSV (BRSV) infection.
The researchers found that, in seronegative calves, PanAd3-RSV alone and in combination with MVA-RSV induced neutralizing antibodies and cellular immunity. They also provided protection against heterologous BRSV challenge-induced upper and lower respiratory tract infection and pulmonary disease.
After BRSV challenge, there was no evidence of enhanced pulmonary pathology or enhanced respiratory disease in vaccinated calves.
Christopher A. Green, PhD, from the University of Oxford in the United Kingdom, and colleagues performed a phase 1 trial in 42 healthy adults to examine the safety and immunogenicity of four different combinations of prime/boost vaccinations.
The researchers found that the vaccines were safe and well tolerated. In response to intramuscular (IM) prime with PanAd3-RSV and after IM boost for individuals primed by the intranasal route, RSV neutralizing antibody titers rose. RSV-specific T-cell responses were increased after the IM PanAd3-RSV prime, with the most efficient boost by IM MVA-RSV.
“PanAd3-RSV and MVA-RSV are safe and immunogenic in healthy adults. These vaccine candidates warrant further clinical evaluation of efficacy to assess their potential to reduce the burden of RSV disease,” Green and colleagues write.
Several authors from both studies are named inventors on patent applications relating to RSV antigen expression systems. One author from the Green study disclosed ties to pharmaceutical companies.