4 ms·The vaccine is so effective that tests are unable to determine who has received it.by unanswered 5y agoThe vaccine is so effective that tests are unable to determine who has received it.ttyprintk 5y agoIncorrect. It takes about 4 weeks before you swab negative after vaccination.fortran77 5y agoThat's not true. I needed to take a test to verify that I really had the vaccine to enter Israel.