And that's because this is the stage when the body begins to produce antibodies. So we have antibodies floating in our blood that are specific to this virus. And these antibodies can be used to detect that virus in our body. So middle stage can last from several months to several years. So no visible symptoms, low levels of that virus. We have the presence of these antibodies and we have a very slow but very continual decline in the population of our helper T cells.