It means to remove the parts of the virus that allow it to replicate or cause harm, I think often that's done by removing some of the genetic material of the vi

It means to remove the parts of the virus that allow it to replicate or cause harm, I think often that's done by removing some of the genetic material of the virus, but it can also be done by damaging its envelope or other methods that would prevent it from being virulent (aka replicating and causing harm)