Unfortunately no. So many types of microbes can cause sepsis that it is not practical to create a vaccine. We can immunize against strep pneumonia and influenza but not other common causes of sepsis. Our diet can greatly influence our chances of developing sepsis and its complications. Omega 3 fatty acids are protective against the worst forms of sepsis. So take fish oil or eat lots of deep water fish.
Not exactly. Sepsis is the body's generalized inflammatory response to an infection. Any kind of infection can cause sepsis. There is no vaccine against the inflammatory response, because that is part of your immune system. However, vaccines against specific infection-causing bacteria (pneumococcus, h. Influenza) are effective at reducing infections, and therefore reduce, but don't eliminate, sepsis.