According to new research, the antiviral molnupiravir does not reduce coronavirus hospital admissions or deaths in vaccinated people at high risk.
But the treatment was associated with a shorter recovery time of up to four days and a reduced viral load.
The study reported that people who took molnupiravir felt better compared to those who received regular care.
The researchers suggest that while the drug may have some benefits in terms of symptom reduction, given the study findings, the cost of the drug may mean it’s not the best choice for the general population.
But they added it could be useful in reducing pressure on UK health systems.
The drug is one of the most expensive antivirals used to treat Covid, and a seven-day course costs around US$700, the equivalent of £577.
Molnupiravir (brand name Lagevrio) was the first treatment (Panoramic) studied by a platform-adaptive trial of new antivirals for the early treatment of Covid-19 in the community.
The study was set up to determine which high-risk groups of people are most likely to benefit from new antiviral treatments for the virus.
Chris Butler, professor of primary care in the Nuffield Department of Primary Care Health Sciences and co-lead researcher at Panoramic, said: “Finding effective, safe and scalable early treatments for Covid-19 in the community is the next important frontier in our research to respond to the ongoing epidemic worldwide.
“It is the community where treatments can have great reach and impact.
“But decisions about who to treat should always be based on evidence from rigorous clinical trials involving people for whom the drugs will most likely be prescribed.”
“We must not forget about the other ongoing epidemic of antibiotic resistance, which is due in part to the large-scale use of antimicrobial drugs, before conducting rigorous clinical trials to find out who really benefits from the treatment.”
But Prof Butler said there may be some situations where the decision to use the treatment can be made.
He explained: “For vaccinated, at-risk patients, this research suggesting that molnupiravir therapy will reduce the likelihood of hospitalization or death on its primary outcome, although molnupiravir therapy has not shown any benefit on its primary outcome, the research suggests that this therapy may have other benefits, such as a faster recovery time and in healthcare. when used to treat Covid-19 for reasons such as less follow-up.
“This can help alleviate the burden on UK health care through home treatment of selected patients during times of high disease burden and pressure on key services.
“Therefore, we hope this new evidence will be useful to policymakers as they devise strategies to manage Covid-19 infections over the winter.”
Study participants were either healthy within five days of symptom onset and over 50 years of age, or aged 18-50 years, with underlying health conditions that made them clinically more vulnerable.
A total of 25,786 subjects were randomly assigned to receive either molnupiravir or standard NHS care.
Explaining the findings, Professor Judith Breuer, director of the UCL Pathogen Genomics Unit, said: “The results generated by the UCL substudy show that participants who received molnupiravir cleared SARS-CoV-2 more quickly than those who received normal care alone.
“As part of Panoramic, we continue to investigate the effect of the drug on the genome (genetic material) of the virus and on the antibody responses of the participants.”
Professor Sir Jonathan Van-Tam, vice-chancellor of the University of Nottingham School of Medicine and Health Sciences and co-author of the study, said: “While molnupiravir was initially found to work well in reducing hospitalizations in Covid patients, these were unvaccinated patients.
“This latest study replicated exercise in the highly vaccinated population, showing that vaccine protection is so strong that there is no apparent benefit of the drug in terms of further reducing hospitalizations and deaths.
“However, both symptom duration and virus spread have decreased significantly and we need to wait much longer to know if there will be any noticeable effects on the long Covid.”
The findings were published in the journal The Lancet.