More bumps on the vaccine road

Abstract

This chapter discusses the bumps on the vaccine road. The challenge to produce effective and safe vaccines for the currently prevalent infectious diseases of humans and animals has become increasingly difficult. In veterinary medicine, evidence implicating vaccines in triggering immune-mediated and other chronic disorders (vaccinosis) is growing. Although some of these problems have been traced to contaminated or poorly attenuated batches of vaccine that revert to virulence, others apparently reflect the host's genetic predisposition to react adversely on receiving the monovalent or polyvalent products given routinely to animals. The onset of adverse effects of vaccination can be expressed as an immediate hypersensitivity or anaphylactic reaction; an acute event occurring 24–72 hours afterwards, or 10–28 days later in a delayed-type immunologic response, or even later as seen with mortality from high-titered measles vaccine in infants, canine distemper antibodies in joint diseases of dogs, and feline injection-site fibrosarcomas. These adverse vaccine reactions typically include fever, stiffness, sore joints and abdominal tenderness, susceptibility to infections, neurologic disorders and encephalitis, collapse with autoagglutinated red blood cells and icterus (autoimmune hemolytic anemia [AIHA]), or generalized petechiae and ecchymotic hemorrhages (immune-mediated thrombocytopenia [ITP]).