A self-amplifying mRNA vaccine ARCT-154, has shown promising results against Covid-19 in ongoing phase trials.
Traditional vs. Self –Amplifying mRNA
A traditional mRNA vaccine, use messenger RNA that encodes the spike protein of the coronavirus.
In other words, the mRNA directs the cell to produce copies of the spike protein, so that the immune system will recognise the spike if and when actual infection takes place, and mount a response.
A self-amplifying mRNA vaccine is an improvement on the traditional RNA platform. It encodes four extra proteins in addition to the vaccine antigen, and these enable amplification of the original strand of RNA once inside the cell.
This highly specialized system lets the virus make multiple copies of its RNA genome, and therefore encoded proteins, from just a single RNA template.
The basic advantage is that it requires a smaller dose.
Also, the new vaccine may come with significant advantages: easier storage, along with lower cost because its ‘self-amplifying’ design allows for smaller doses.
