Chloroquine must be taken with zinc. The zinc is then more easily transported into the cell and the cell is then unable to replicate the virus. A later study recommends Hydroxychloroquine 500 mg twice daily with zinc. Hydroxychloroquine is more readily available and the dosage is a lot lower than is required by using CHloroquine.
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa237/5801998