I don't honestly remember, and I'm not sure if it's less likely to happen if downloading using the Itch app rather than directly.
If your virus scanner doesn't like the file because it doesn't recognise it (probable), usually it just wants to send it to the lab to check it's okay before letting you open it (unless you change the settings of your security software).
Or is it Chrome flagging up the file as suspicious? If so you can override the setting and scan the downloaded file with your security software to make sure before launching it.
Sorry for the late response btw!