Their overall strategy is to look at respiratory infections more generally for the longer term.
Researchers looking at Covid-19 treatments for the over 50s are considering including younger people in the trials as issues surrounding long Covid become clearer.
Principle is a nationwide clinical trial platform from the University of Oxford to find coronavirus treatments that can be taken at home by those aged 50 and over.
The researchers are looking for medicines that can help people with Covid-19 symptoms get better quickly and stop them needing to go to hospital.
But they are now considering expanding the scope of their trial.
Chris Butler, co-lead of the Principle trial – and professor of primary care, Nuffield Department of Primary Care Health Services, University of Oxford, said: “The bottom age is 50, and yes we are giving serious consideration to dropping that as the nature of the illness, gets better understood and issues about, perhaps longer term effects of this condition, become clearer.
“It is worth us considering the risks of other things apart from hospitalisation.
“So, we are thinking about reducing the age, and that would be part of our overall strategy here to develop this platform trial into a sustainable trial that could look at respiratory infections more generally for the longer term, looking at a wider range of outcomes.”
The experts say there are a number of studies compiling observational data on what long Covid may look like, but interventions will need to be tested.
Prof Butler added: “The issue of long Covid might be something that really compels us to look at a broader range of inclusion, and to see whether the interventions are effective in reducing these other adverse outcomes from Covid.”
Prof Butler explained it would be unlikely that a “perfect vaccine” that protects everybody will be found, and people will still get the disease.
“Therefore, finding treatments in therapeutic trials that are also beneficial will continue to be important,” he said.
The Principle trial is testing whether low-risk treatment in the community can help people at higher risk of complications from Covid-19 to get better quicker, reducing the need for hospital admission.
More than 1,400 participants have been recruited since the trial launched in April, and 1,000 GP practices are helping to recruit patients into the trial.
The trial is evaluating two common antibiotics, azithromycin and doxycycline.
The researchers say some studies have shown that azithromycin increases the pH level within parts of human cells interfering with the ability of Sars-CoV-2, the virus that causes Covid-19, to bind to human cells, as well as interfering with its ability to replicate and spread within human cells.