“Why can’t we treat viral and bacterial infections with the same medication?”
Although the symptoms of viral and bacterial infections can be similar, and they spread in similar ways, bacteria and viruses are very different. A bacterium is a living cell, albeit a simple one compared to a human cell. It shares features with a human cell, like a cell membrane and DNA, and they have similar needs for energy. A virus is even simpler. The scientist Peter Medawar described viruses as “a piece of bad news wrapped in a protein coat”. Outside of a living cell, they don’t grow, use energy or reproduce themselves, which are normally considered to be signs of a living organism. They just exist. They don’t even always use DNA, the double-stranded helix which carries genetic information. Some of them use RNA, which has only a single strand.
It’s when it gets into the right kind of living cell that a virus can really take off. It uses the host cell to make more and more copies of itself, churning them out to infect more and more other cells. By contrast, a bacterial cell can replicate itself.
When you’re infected with either a virus or a bacterium, the symptoms you experience are a result of the damage the infection is doing to your body, plus your body’s own response to try and kill the infection. For example, inflammation can cause pain and discomfort, but it’s a protective mechanism involved in responding to infection. The symptoms of viral and bacterial infections can be treated using the same medication. A stuffy nose is a stuffy nose, regardless of whether it’s caused by a bacterium or a virus, and that’s why a decongestant spray will work in both cases.
What about antibiotics, though? Although “anti” means “against” and “biotic” just means “associated with or derived from living organisms”, antibiotics don’t actually harm all living organisms. If they did, we wouldn’t be able to take them. Instead, they could more accurately be called “antibacterials”. They target bacteria, sometimes very specifically. That means that they have no way of interacting with a virus, which is hidden inside your body’s own cells. They’re also ineffective against other pathogens, like fungi (so antibiotic cream won’t do anything for your athlete’s foot).
This is where antivirals come in. These can attack viruses, but they do so in a different way, by inhibiting their development in various ways.
So when you have a sore throat and you go to the doctor, they probably won’t prescribe you antibiotics. For one thing, we need to hold back our antibiotics to fight against deadly diseases. For another, your sore throat could easily be caused by a virus, in which case the antibiotic will do nothing but upset your digestive system.