Mycophenolic acid can promote the emergence of new SARS-CoV-2 virus variants

A research team from the Leibniz Institute of Virology (LIV), the University Medical Center Hamburg-Eppendorf (UKE) and the Ruhr University Bochum has discovered that the immune-inhibiting agent mycophenolic acid (MPA) can promote the emergence of new SARS-CoV-2 virus variants. The results were published in the journal Proceedings of the National Academy of Sciences (PNAS).

The study identified certain changes that occurred in the genetic material of SARS-CoV-2 (mutations S P812R, ORF3 Q185H and E S6L). The active ingredient MPA therefore has an antiviral effect, but viruses such as SARS-CoV-2 can circumvent the mechanism by adapting. 

“Our results show how important it is to evaluate antiviral agents also with regard to possible viral adaptations: This is particularly important in immunocompromised people in order to recognize the emergence of new virus variants at an early stage and to be able to take targeted countermeasures,” explains Prof. Stephanie Pfänder, research group leader at the Leibniz Institute of Virology.

The active substance MPA, a so-called antimetabolite, is used to specifically suppress the immune system, especially after transplantation of organs such as kidneys, liver or heart, in order to prevent rejection of the new organ. MPA also inhibits the replication of various viruses, including SARS-CoV-2, the respiratory syncytial virus (RSV) and the Mpox virus (MPXV). However, the studies have shown that the virus can bypass this inhibition.

Publication: Meister, Pfaender et al. Mycophenolic acid treatment drives the emergence of novel SARS-CoV-2 variants. Proc Natl Acad Sci U S A. 2025 Jul 15;122(28):e2500276122. doi: 10.1073/pnas.2500276122.