Grid: “The evidence overwhelmingly suggests that fake CDC vaccination cards are widespread in the United States. An Economist/YouGov poll reported 12 percent of American adults under 30 knew someone with a fake vaccine card. TMZ covered fake cards. A fake vaccine card was a punchline for a Saturday Night Live sketch.” “Each false credential weakens the credibility of every real card, experts and officials say, diminishing the overall reliability of the cards as proof of vaccination.