Frédéric Tangy
Viral Genomic and Vaccination Unit, Institut Pasteur, CNRS UMR 3569, Paris, France
Abstract:
Over the last two decades a number of new viral diseases such as SARS, MERS or Nipah virus infections have emerged at the animal-human interface, and infections such as Ebola and Lassa viruses, or recently Zika virus, have expanded beyond their usual limited territories. Each time, the global community failed to develop effective interventions in a timely manner. We adapted the use of live attenuated measles vaccine, one of the safest and most efficacious vaccines available, as a platform for the delivery of these new antigens.
Measles vaccination has been used for more than 40 years in over 1 billion children and is 95% efficacious after one or two administration. Measles vaccine is genetically stable and reversion to pathogenicity has never been observed. Taking advantage of these characteristics, we developed the attenuated measles Schwarz vaccine virus into a versatile chimeric or recombinant vector.
Proof of concept in humans for this technology has recently been demonstrated for a measles-chikungunya vaccine. Human trial showed that the vaccine was well tolerated and induced a robust and functional antibody response after 1 (90%) or 2 immunizations (100%). This trial also demonstrated that pre-existing measles antibodies did not impair the immunogenicity of the heterologous antigen, indicating that pre-immunity to measles due to vaccination or infection should not restrict the use of recombinant measles vector for new vaccines. Many other antigens from HIV, DENV, CHIKV, WNV, SARS, H5N1, Ebola, Zika, and Plasmodium have been expressed in this vector and their strong immunogenicity or protective capacity has been established in preclinical animal models, also in the presence of pre-existing measles immunity, highlighting the potential of measles vector as a platform for rapid response to new pathogens. Some of these results will be presented.