New types of drug intended to be used in place of antibiotics could actually increase the spread of diseases, Scottish researchers have warned.
The treatments, currently being developed by the pharmaceutical industry, work by limiting the symptoms caused by a bug or virus in the body, rather than killing it outright, in efforts to combat drug resistance.
Scientists at Edinburgh University have given a cautious welcome to the drugs, but they warned that, in some cases, they could actually contribute to the spread of illness.
The researchers, led by Dr Pedro Vale, have been probing the long-term effectiveness of the drugs currently in development, as well as other treatments already in use, such as anti-inflammatory therapies which also combat symptoms rather than the cause of illness.
The new drugs are being created as concern continues to grow that the antibiotics currently so crucial to tackling often serious diseases could become useless as infections become increasingly resistant to them.
Last year, there were warnings that the danger posed by growing resistance to antibiotics should be ranked along with terrorism as a national threat.
The new approach to creating drugs involves helping the patient to tolerate disease, by combating the symptoms, and buying the immune system valuable time to get rid of the infection naturally.
The researchers in Edinburgh, along with colleagues in Liverpool, created a mathematical model to look at how drugs that limit the damage caused by disease could affect how infections spread and evolve.
But the scientists, writing in the journal PLoS Biology, cautioned that people given damage-limitation treatments may appear healthy, because their symptoms have been treated, but they still carry high levels of infection and so may be more likely to pass on disease.
This could include illnesses such as flu and others spread by coughs and sneezes.
In addition, people with lesser symptoms, treating themselves with over-the-counter drugs, could remain undiagnosed and add to the spread of disease.
Dr Vale, from Edinburgh Univeristy’s School of Biological Sciences, said: “In treating infections with drugs, we change their environment, but bacteria and other infectious agents are incredibly good at adapting.
“Damage-limitation therapies may be a useful alternative to antibiotics, but we should be cautious, and investigate their potential long-term consequences.
“Limiting damage may work for the individual but could, in some cases, increase disease spread.”
Andrew Powrie-Smith, director of Association of the British Pharmaceutical Industry Scotland, said: “Advances in medicine are enabling people to live longer and overcome diseases such as Scotland’s ‘big three’ – cancer, stroke and heart disease – drastically improving the outcomes for countless patients and their families.
“New medicines that are being developed by the pharmaceutical industry are an investment in patient care.”