Molnupiravir was first described in 2003. Its discoverers found that it inhibited the growth of bovine viral diarrhoea virus and hepatitis C virus, and proposed that it may be a promising treatment for hepatitis C.
It works by creating errors in the virus’s genetic code, known as mutagenesis. Each time the virus replicates in the presence of molnupiravir, more and more errors accumulate, eventually building up to an “error catastrophe” that stops the virus from functioning.
The problem is, mutagenic drugs may also cause mutations in the RNA of the cells of the individuals taking them.