First, it should be mentioned that many (most?) viruses don't cause a problem for humans. Second, many of them are "bacteriophages", that is, they prey on bact

First, it should be mentioned that many (most?) viruses don't cause a problem for humans. Second, many of them are "bacteriophages", that is, they prey on bacteria, including bacteria that can make us sick. So, by 2124 we may understand which viruses are beneficial, similar to how we are beginning to understand which bacteria are beneficial (hence "probiotic" food). Third, by 2124 we might be able to design viruses to achieve a given affect, either on ourselves or on an enemy. Fourth, some viruses survive by inserting themselves into the host DNA, normally remaining there as non-coding DNA but some of them able to reactivate in certain circumstances. This means viruses might be harder to eliminate, but also that they might be used as a means of improving our DNA in some way. Just a few thoughts; I am not a geneticist.