I know someone who had to have her antibodies tested (before working in a lab), and realized vaccines were less effective for her (she had half to a quarter of

I know someone who had to have her antibodies tested (before working in a lab), and realized vaccines were less effective for her (she had half to a quarter of necessary antibodies) and had to retake a lot of boosters, including 'mmr' (it has another name here) and hepatitis.