1. The problem statement, all variables and given/known data The health care workers involved in taking care of patients affected by diseases like influenza have to be vaccinated annually. Is the above statement true? Give reason for your answer. 2. Relevant equations Not applicable here I think so. 3. The attempt at a solution Why they should be they vaccinated by the way. By handshaking can the virus infect other one or can it travel from air through nose into someone's else body? One time vaccination produces antibodies to fight a particular virus or bacteria or fungi. Then what is case with this influenza?