https://www.lifesitenews.com/news/us-govt-to-issue-wallet-sized-covid-19-proof-of-vaccination-cards

The technology involved in administering the vaccine, as used by Pfizer and Moderna, is so novel that it has yet to be approved by the Food and Drug Administration, as admitted by Pfizer itself. 
It also avails of “messenger RNA,” which directly affects a person’s cells, and is “a vaccine technology that’s so new, no mRNA vaccines have ever been approved by the Food and Drug Administration.”
Doctors from the Advisory Committee on Immunization Practices (ACIP), advising the CDC, warned that patients needed to be informed about the side-effects of COVID-19 vaccines. According to a report from CNBC, Dr. Sandra Fryhofer of the American Medical Association stressed, “We really need to make patients aware that this is not going to be a walk in the park,” she said. “They are going to know they had a vaccine. They are probably not going to feel wonderful. But they’ve got to come back for that second dose.” 

Some of the immediate results from some of the vaccine trials have included “severe” complications, involving headaches, fever, body aches and symptoms similar to a “severe hangover.