Molnupiravir inhibits SARS-CoV-2 variants including Omicron in the hamster model
Syrian hamster study showing efficacy of molnupiravir for multiple variants including omicron.Concerns have been raised that the mutagenic mechanism of action may create dangerous variants or cause cancer [Hadj Hassine, Swanstrom]. See [Fountain-Jones, Sanderson, ] for analysis of variants potentially created by molnupiravir.
Rosenke et al., 17 May 2022, United Kingdom, peer-reviewed, 11 authors.
Title: Molnupiravir inhibits SARS-CoV-2 variants including Omicron in the hamster model
Authors: Kyle Rosenke1, Atsushi Okumura1, Matthew C. Lewis1, Friederike Feldmann2,
Kimberly Meade-White1, W. Forrest Bohler1, Amanda Griffin1, Rebecca Rosenke2, Carl Shaia2,
Michael A. Jarvis1,3,4*, Heinz Feldmann1*
Affiliations: 1Laboratory of Virology, 2Rocky Mountain Veterinary Branch, National Institute
of Allergy and Infectious Diseases, National Institutes of Health; Hamilton, MT, USA; 3School
of Biomedical Sciences, University of Plymouth; Plymouth, Devon, UK; 4The Vaccine Group
Ltd; Plymouth, Devon, UK.
*Corresponding authors: Heinz Feldmann, Rocky Mountain Laboratories, 903 S 4th Street,
Hamilton, MT, US-59840; Tel: (406)-375-7410; Email: email@example.com;
Michael A. Jarvis, University of Plymouth, School of Biomedical Sciences, Derriford Research
Facility, Plymouth, Devon, UK, PL6 8BU; Tel: +44 (0)1752-437444; Email:
One Sentence Summary: MK-4482 inhibits replication of multiple SARS-CoV-2 variants of
concern, including Omicron, in the Syrian hamster COVID-19 model
Conflict of Interest Statement: The authors have declared that no conflict of interest exists.
The recent emergence of the SARS-CoV-2 Omicron variant of concern (VOC) containing a
heavily mutated spike protein capable of escaping preexisting immunity identifies a continued
need for interventional measures. Molnupiravir (MK-4482), an orally administered nucleoside
analog, has demonstrated efficacy against earlier SARS-CoV-2 lineages and was recently
approved for SARS-CoV-2 infections in high-risk adults. Here we assessed the efficacy of MK-
4482 against the earlier Alpha, Beta and Delta VOCs and Omicron in the hamster COVID-19
model. Omicron replication and associated lung disease in vehicle treated hamsters was reduced
compared to the earlier VOCs. MK-4482 treatment inhibited virus replication in the lungs of
Alpha, Beta and Delta VOC infected hamsters. Importantly, MK-4482 profoundly inhibited virus
replication in the upper and lower respiratory tract of hamsters infected with the Omicron VOC.
Consistent with its mutagenic mechanism, MK-4482 treatment had a more pronounced inhibitory
effect on infectious titers compared to viral RNA genome load. Histopathologic analysis showed
that MK-4482 treatment caused a concomitant reduction in the level of lung disease and viral
antigen load in infected hamsters across all VOCs examined. Together, our data indicate the
potential of MK-4482 as an effective antiviral against known SARS-CoV-2 VOCs, especially
Omicron, and likely future SARS-CoV-2 variants.
Please send us corrections, updates, or comments. Vaccines and
treatments are complementary. All practical, effective, and safe means should
be used based on risk/benefit analysis. No treatment, vaccine, or intervention
is 100% available and effective for all current and future variants. We do not
provide medical advice. Before taking any medication, consult a qualified
physician who can provide personalized advice and details of risks and
benefits based on your medical history and situation. FLCCC
provide treatment protocols.