There has been a lot of research into how long antibiotic courses should be, to determine the shortest possible length of course needed to completely kill all bacteria.
If you are being treated for an infection, the kind of antibiotics your doctor prescribes and the length of the course should be based on the best evidence.
If you stop treatment early, there is a risk the antibiotics won’t have killed all the bacteria that made you sick and that it will mutate and become resistant. This will not happen to everyone – the problem is that we don’t know who can safely stop treatment early.
By taking the full course prescribed by your doctor, even if you start to feel better earlier, you increase the chances of killing all of the bacteria and reduce the risk of resistance.
WHO has published many guidelines about treatments for different infections and has recommended treatment durations and doses of antibiotics based on the best clinical evidence for each case.
Sometimes these recommendations are for shorter course of antibiotics than previously recommended, because new research shows shorter courses have the same effect as longer courses on cure and symptoms. In these cases, shorter treatments make more sense – they are more likely to be completed properly, have fewer side effects and also likely to be cheaper.
The bottom line is, your doctor should have had years of training and access to the latest evidence – so listen to them. Whatever the length of the course of antibiotics – take the full prescription.