Question: Why are viruses so hard to cure?

Alena Pance answered on 11 Jun 2020:

Hi Sofia, viral diseases are difficult because generally, viruses use the machinery of the cells they invade to replicate themselves. This means that most of the crucial proteins that could be targets for an immune response or for drug development are actually the host’s. So, we cannot inhibit them because that would inhibit vital functions in the body potentially cause serious damage. Nor can we induce immunity against them with a vaccine for example because they are ‘self’ so the immune system won’t recognise it to start with and if it does then there is a serious risk of triggering an autoimmune disease. The proteins that are exclusive to the virus and ‘visible’ to the immune system are few and can vary quite a lot meaning that a vaccine for example would induce a limite immune response. Many of these proteins do not have a specific activity that can be inhibited but are rather structural, so even developing drugs is very challenging. But vaccines have been achieved, like for flu. but because flu virus varies a lot, then a vaccine that is effective one year will nto work in another year when the virus has changed significantly, this is why there is a different vaccine every year.