A new study throws doubt on claims that molnupiravir can reduce COVID-19 hospital admissions. 

Previous studies had suggested that the drug is effective at reducing hospital admissions in patients with mild to moderate COVID-19, leading the World Health Organization (WHO) to recommend its use for patients with the highest risk of hospital admission. 

However, most of those studies were conducted in largely unvaccinated populations and prior to the emergence of the omicron variant. 

But a new UK trial has been carried out in a majority vaccinated population where most COVID-19 infections were the omicron variant, making it more applicable to the present situation in most nations. 

It found that molnupiravir (taken as an 800mg dose twice daily for five days) does not reduce hospital admissions or deaths in vaccinated adults with COVID-19 infection who are at higher risk of mortality. However, the patients treated at home with molnupiravir recovered quicker compared to the control group.

“Although this trial found no benefit from molnupiravir treatment on its primary outcome - which hypothesised that treatment with molnupiravir for vaccinated, at-risk patients would reduce the likelihood of hospitalisation or death - the trial suggests that this treatment could have other benefits when being used to treat COVID-19, such as a faster recovery time and reduced follow up with health services. This could help to ease the burden on UK health services through the treatment of selected patients at home, during times of high disease burden and pressure on key services.  We therefore hope this new evidence will be of use to policymakers when preparing strategies for managing COVID-19 infections over the winter,” says lead author, Professor Chris Butler from the University of Oxford.

The study included 25,708 participants over the age of 18 (average age 57 years) with a higher risk of death or hospitalisation from COVID-19 infection from health centres across the UK. 

Patients were considered at higher risk of hospitalisation or death if they were aged 50 years or older - or aged 18 years or older with relevant underlying health conditions. Patients had a confirmed omicron COVID-19 infection and were unwell for five days or less before beginning treatment.

Writing in a linked Comment, Professor Michael Kidd from Australian Government Department of Health and Aged Care, who was not involved in the study, said; “Butler and colleagues acknowledge that their findings might be ‘less applicable’ in people with COVID-19 who are extremely clinically vulnerable. 

“We would go a step further and urge caution in seeking to apply the findings of this study to those at highest risk from COVID-19 complications… there are important policy implications in the study’s secondary endpoints. 

“The trial showed that the addition of molnupiravir to usual care resulted in faster time to recovery and reduced viral detection and load (in a small virology substudy). 

“The shortened and sustained symptom reduction, together with the effects on viral clearance, could be an important consideration in high-risk settings, such as care homes, in terms of potentially minimising the spread of infection among high-risk people. 

“Molnupiravir might also provide benefits to health-care systems, especially during community surges, by potentially allowing health workers to return safely to work sooner.”

Australia’s National COVID-19 Clinical Evidence Taskforce has updated its listing for molnupiravir (sold as Lagevrio), after considering data from the large-scale trial in the UK.