Late treatment studies.
Most studies focus on late treatment with hospitalized patients, and the results are very mixed. We found 28 of the studies reported positive effectiveness, while 19 reported negative effectiveness, both with varying degrees of effect and confidence. We do not consider the late treatment studies further here since we are concerned with early treatment, other than to note that these studies suggest HCQ may potentially be beneficial in a hospital setting if used very quickly and with patients that have not reached a more advanced stage of the disease; and it may be of limited or negative value with later stage disease. Three studies consider higher dosages than typically used
[Borba, Horby, World Health Organization (B)], and the results suggest that these dosages in late stage patients may be harmful.