pubmed is the word you use to get scientific studies in a google search and it might not have been hcQ it could've been cQ.
https://www.ncbi.nlm.nih.gov/pubmed/15351731
In vitro inhibition of severe acute respiratory syndrome coronavirus by chloroquine.
there were 2 of them from 04-05
the other one was longer, and, interestingly, mentioned NH4Cl as also being good.
You can buy
https://www.premier1supplies.com/p/ammonium-chloride?gclid=EAIaIQobChMItfyis5Xc6AIVmrh3Ch38cAWVEAkYASABEgJPZfD_BwE
Ammonium Chloride - 5 pounds for $5 - for animals.
No idea what the dosage might be for humans, but they did the test and it worked about as well as chloroquine.
heres the pubmed link for that
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1232869/
Ammonium chloride inhibits SARS-CoV infection of Vero E6 cells
Since chloroquine inhibited SARS-CoV infection when added before or after infection, we hypothesized that another common lysosomotropic agent, NH4Cl, might also function in a similar manner. Ammonium chloride has been widely used in studies addressing endosome-mediated virus entry. Coincidently, NH4Cl was recently shown to reduce the transduction of pseudotype viruses decorated with SARS-CoV spike protein [17, 18]. In an attempt to examine if NH4Cl functions similarly to chloroquine, we performed infection analyses in Vero E6 cells before (Fig. (Fig.4A)4A) and after (Fig. (Fig.4B)4B) they were treated with various concentrations of NH4Cl. In both cases, we observed a 93–99% inhibition with NH4Cl at ≥ 5 mM. These data indicated that NH4Cl (≥ 5 mM) and chloroquine (≥ 10 μM) are very effective in reducing SARS-CoV infection. These results suggest that effects of chloroquine and NH4Cl in controlling SARS CoV infection and spread might be mediated by similar mechanism(s).