Mpox Goes mRNA

When mpox started spreading in previously non-endemic countries in 2022, smallpox vaccines were deployed to slow the spread of disease and protect at-risk individuals. However, as vaccine technology evolves to drive better humoral and cellular immunity – and as mpox itself evolves and spreads worldwide – scientists are working to develop vaccines that specifically target mpox and provide greater protection against the virus.

Now, researchers from the National Institute of Allergy and Infectious Diseases and Moderna have developed an mRNA–lipid nanoparticle-based vaccine that encodes four highly conserved mpox antigens linked to virus binding, entry, and transmission (1). In their recent study, they investigated whether it provided protection against mpox infection comparable to modified vaccinia virus Ankara (MVA) – an attenuated strain of vaccinia virus (VACV) that forms the foundation for current vaccines against smallpox and mpox. 

The results showed that the mRNA vaccine induced mpox-specific immunity and heterologous protection when challenged with lethal vaccinia virus. It also provided superior neutralizing activity against both mpox and VACV compared with MVA. Although both the quadrivalent mRNA vaccine and MVA protected against lethal challenge, the mRNA vaccine was superior at protecting against weight loss even at a lower dose. Moreover, the vaccine induced higher Fc effector TH1-biased humoral immune responses to the four antigens encoded by the vaccine.

Are you interested to learn more about the bright future of mRNA vaccines? Check out this article!