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Longer course of antiviral treatment required to combat COVID-19 infections

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28 February 2024

Study conducted as part of PANORAMIC platform trial finds that the current recommended five-day course may not be the adequate length to treat COVID-19 infections

The virology sub-study analysed the viral samples given by 577 of the trial participants who had been randomised at the start of the study to receive either usual care or the five-day course of mulnopiravir, an antiviral treatment identified for its potential effectiveness in combatting COVID-19 infections. 

Findings from the virology sub-study involving UCL researchers have now been published in Nature Communications that indicate molunpiravir initially lowered patients’ viral load more quickly than usual care. However, the results also show that after treatment has completed, the rate of viral decline in molnupiravir-treated participants significantly slowed. More mutations were observed in samples received from molnupiravir-treated patients with researchers able to grow the virus in lab conditions up to nine days post-treatment.

The study was undertaken as part of the ongoing PANORAMIC trial aiming to find out in which people new antiviral treatments for COVID-19 in the community reduce the need for hospital admission and get better sooner. The study recruited patients from the public and GP Practices across the country, including London. Medicus Health Partners were one of the first four primary care sites in the UK to start offering the study to patients on day one of the trial.

Lead author Professor Joseph Standing (UCL Great Ormond Street Institute of Child Health) said:

“We know that molnupiravir works by introducing errors into the SARS-COV-2 virus – which causes COVID-19. Mutated variations of the virus often cannot replicate well and this is why we saw faster viral load decline.

However, the fact the virus remains in patients after the five-day molnupiravir treatment course indicates the course is not long enough to clear the virus from the body.

It is possible that these patients could be spreading virus that has mutated and, if large numbers of patients are treated in this way, it is possible new variants, that help the virus evade the human immune system more effectively, may arise.”

Dr Oliver van Hecke, Senior Clinical Research Fellow at the University of Oxford and co-author of the study, said.

“These findings raise important questions about the impact of molnupiravir on patients' immunity.

Even if taking molnupiravir for longer fully gets rid of the virus, some patients might still develop weaker protection against catching it again in the future. It would be useful to explore whether molnupiravir together with other antiviral drugs in combination better eliminates the virus, and ensure patients build up good immunity against it. This could help prevent treated patients from catching it again soon after and also reduce the chance of passing on mutated viral strains."

The PANORAMIC trial (Platform Adaptive trial of Novel antiviRals for eArly treatment of COVID-19 In the Community) is led by the Primary Care Clinical Trials Unit at the University of Oxford. The trial is funded by the Department of Health and Social Care through the National Institute for Health and Care Research. Further information on the trial is available from the study website.

The findings form the virology sub-study can be read in Nature Communications: Randomized controlled trial of molnupiravir SARS-CoV-2 viral and antibody response in at-risk adult outpatients

University College London supported the sub-study and further information is available in their news article: COVID-19 antiviral treatment should be taken for longer



Image: Wikimedia Commons