There are a variety of speech-related symptoms that can be associated with apraxia, including: Difficulty stringing syllables together in the appropriate order to make words, or inability to do so. Minimal babbling during infancy. Difficulty saying long or complex words.
1 Understand that hepatitis B vaccination-induced protective antibodies can last for up to 15 years, but appear to fall off over time.
Immunizations with 30+ answers. Assuming the question actually seeks to know how long protection provided by the hepatitis B (HBV) vaccine lasts, the available data suggests >20 years from time of last shot. There are several HBV vaccines and HBV vaccine manufacturers (see Table below from 1).