Measles virus vector as a transgene delivery platform for vaccination
The common, replicating measles vaccine virus is highly immunogenic and one of the safest live attenuated vaccines worldwide. Recombinant measles vectors can be used to deliver pathogen-specific antigens (e.g. from a coronavirus) to induce pathogen-specific vaccination effects.
SARS-CoV-2 is a coronavirus that newly emerged in late 2019 in China. The virus causes a new severe acute respiratory syndrome (SARS) referred to as COVID-19. SARS-CoV-2 is highly contagious and was declared pandemic by the WHO on 11th of March 2020. By June 2020, more than 6,000,000 people in about 200 countries were infected and more than 380,000 infection-related deaths were reported. There was no known vaccine or antiviral treatment available. The safety and long-term efficacy of many vaccine candidates in development were unknown. Governments across the world forced people into quarantine and issued preventive measures to contain the pandemic. This caused a major global social and economic disruption that showed the need for the development of novel, platform-based vaccine technologies.
We have demonstrated that our measles vector-based platform technology is highly versatile and – in addition to its application in immuno-oncology – it can be used to vaccinate for protection against infectious diseases. Therefore, we encoded SARS-CoV-2 antigens on our measles vaccine vectors and demonstrated the induction of effective cellular and humoral immune responses after administration in animal models.
Balancing immunogenicity and tolerability is key to develop vaccines that are effective and safe at the same time. For COVID-19, using a replicating attenuated coronavirus would be highly immunogenic but bears a potential risk of residual pathogenicity. Using an alternative virus vector system with a defined safety profile, e.g. a measles vaccine backbone, to deliver coronavirus-specific antigens eliminates this potential risk but maintains the quality of a multifunctional immune activation.