Background: The efficacy of bacille Calmette-Guérin (BCG) may be
enhanced by heterologous vaccination strategies that boost the
BCG-primed immune response. One leading booster vaccine, MVA85A (where
MVA denotes modified vaccinia virus Ankara), has shown promising safety
and immunogenicity in human trials performed in the United Kingdom. We
investigated the safety and immunogenicity of MVA85A in
mycobacteria-exposed—but Mycobacterium tuberculosis-uninfected -healthy
adults from a region of South Africa where TB is endemic.
Methods: Twenty-four adults were vaccinated with MVA85A. All subjects
were monitored for 1 year for adverse events and for immunological
Results: MVA85A vaccination was well tolerated and induced potent T cell
responses, as measured by interferon (IFN)-γ enzyme-linked immunospot
assay, which exceeded prevaccination responses up to 364 days after
vaccination. BCG-specific CD4<sup>+</sup>T cells boosted by MVA85A were
comprised of multiple populations expressing combinations of IFN-γ,
tumor necrosis factor (TNF)-α, interleukin (IL)-2, and IL-17, as
measured by polychromatic flow cytometry. IFN-γ-expressing and
were boosted during the peak BCG-specific response, which occurred 7
days after vaccination.
Conclusion: The excellent safety profile and quantitative and
qualitative immunogenicity data strongly support further trials
assessing the efficacy of MVA85A as a boosting vaccine in countries
where TB is endemic.
Hawkridge, A.; Scriba, T.J.; Gelderbloem, S.; Smit, E.; Tameris, M.; Moyo, S.; Lang, T.; Veldsman, A.; Hatherill, M.; van der Merwe, L.; Fletcher, H.A.; Mahomed, H.; Hill, A.V.S.; Hanekom, W.A.; Hussey, G.D.; McShane, H. Safety and Immunogenicity of a New Tuberculosis Vaccine, MVA85A, in Healthy Adults in South Africa. Journal of Infectious Diseases (2008) 198 (4) 544-552. [DOI: 10.1086/590185]
Safety and immunogenicity of a new tuberculosis vaccine, MVA85A, in healthy adults in South Africa.