Vaccines usually produce only subtle clinical side effects, such as local pain due to the infiltration of inflammatory cells at the administration site, and slight fever, reflecting the expected immunological response of the host to the vaccine, similarly to what occurs after a natural infection These symptoms derive from the release of proinflammatory mediators such as the CRP, interleukins and coagulation factors, and are intrinsic of the activation of immune response [23]. This evidence concerns the gene CRP and infection.