1 Understand that hepatitis B vaccination-induced protective antibodies can last for up to 15 years, but appear to fall off over time.  Patients who were vaccinated 10 to 15 years ago, especially those who were vaccinated as children, may not be adequately protected. For patients with this history who are at moderate to high risk of hepatitis B infection consider quantitative hepatitis B antibody measurement to determine protective immunity.
Definition of thickness. 1 : the smallest of three dimensions length, width, and thickness. 2 : the quality or state of being thick. 3a : viscous consistency boiled to the thickness of honeyb : the condition of being smoky, foul, or foggy. 4 : the thick part of something. 5 : concentration, density.
Length. In geometric measurements, length is the longest dimension of an object. In other contexts length is the measured dimension of an object. For example it is possible to cut a length of a wire which is shorter than wire thickness.