Immunization update: A 2011 retrospective on product changes and new recommendations

Key Points

Abstract

Vaccines are one of the greatest achievements of biomedical science and public health. Proper vaccination plays a critical role in the reduction of vaccine-preventable disease and related morbidity and mortality. Despite levels of vaccine-preventable diseases being at or near record lows, many still persist due to numerous underimmunized children, adolescents, and adults. In addition to morbidity and premature deaths, vaccine-preventable diseases impose a high societal and economic burden, including decreased school and work productivity, increased doctor's visits, and hospitalizations. The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention releases updated immunization schedules annually. In the 12 months that span schedule updates, new evidence becomes available and product changes occur. New products are approved by FDA and existing products may obtain approval for additional formulations or further indications. This article reviews certain recommendations and product changes that have occurred during 2011 since publication of the immunization schedules in January/February 2011. The covered vaccines include influenza intradermal and high-dose, herpes zoster, human papillomavirus, quadrivalent meningococcal conjugate, and tetanus toxoid. ACIP guidance affects vaccine practices; pharmacists' knowledge of the most current recommendations can enhance patient education, improve patient care, and potentially result in increased vaccination rates. (Formulary. 2012;47:58–74.)

Immunity involves the body's ability to discriminate "self" from "non-self," allowing the immune system to attack foreign antigens and pathogens in order to protect us from disease, while sparing our own tissues.^5,7 Immunity is typically very specific to a particular organism or group of similar organisms and is generally noted by the presence of antibodies.⁶ Immunity can be acquired by 1 of 2 methods, passive or active. Both can be obtained by either natural or artificial means. Passive immunity is acquired by the transfer of preformed antibodies to unimmunized individuals. This method can occur naturally, as in the transplacental passage of maternal antibodies to a fetus. Artificial passive immunity is achieved by the administration of human immune gamma globulin or antitoxin. Due to lack of memory, this passive immunity will dissipate if not accompanied by active production of antibodies. Active immunity requires exposing an unimmunized person to a pathogenic agent either naturally by exposure to the disease or artificially through vaccination. The largest benefit of vaccination is avoidance of the disease and related complications. Whether obtained naturally or artificially, active immunity confers the additional benefit of immunologic memory, which persists for years and may be permanent. This memory allows B cells to replicate and reestablish protection upon future exposure to the same pathogen.^6–8