Did you sign up thruthrough VAMS (CDC)? If so, you can print out a certificate from there. Is it secure? Not really, but then anybody can print out their own card from PDFs online. It's probably worthwhile having multiple documents as backups.
BTWBy the way, I'm looking at my card, and I just noticed that the provider messed up the date of the second shot, so she crossed it out and wrote the correct date. I suspect there's a wide variety in what they see on these cards.