This following article is a retrospective cohort study that evaluated several treatments for COVID-19 with respect to their progression towards pneumonia.
The results show that the early use of hydroxychloroquine was a protective factor associated with a worsening condition. The results were statistically significant. The clinical improvement by 20 days was also significantly different between patients with hydroxychloroquine used early and those with hydroxychloroquine not used. Also, the median time to clinical improvement better in the hydroxychloroquine used early group, compared with the without hydroxychloroquine used group and with hydroxychloroquine not used early group.
There may be role for the use of hydroxychloroquine, early after the diagnosis of COVID-19 infection. In this study, early meant within 5 days of diagnosis. The treatment was given at least for 3 days.