Vaccine Failure

Definition And Overview

Denotes occurrence of clinical disease in an individual despite receiving vaccination.
Categorized into primary vaccine failure and secondary vaccine failure.
Generally remains rare following administration of measles, diphtheria, and tetanus vaccines.

Feature	Primary Vaccine Failure\|	Secondary Vaccine Failure\|
Core Definition	Inability of recommended vaccine dose(s) to induce an immune response.	Occurrence of clinical disease despite prior successful induction of immune response.
Pathophysiology	Complete failure of initial seroconversion or cell-mediated immunity generation.	Waning of protective immunity and immunological memory over time.
Common Causes	Maternal antibody interference, concomitant infections, cold chain interruptions.	Natural decline in antibody titers, inadequate generation of memory B cells.
Classic Examples	Oral poliovirus vaccine, Measles vaccine.	Bacillus Calmette-Guérin, Pertussis vaccine, Typhoid vaccine.
Management Strategy	Administer multiple primary doses or delay vaccination until maternal antibodies wane.	Administer scheduled booster doses to sustain protective antibody titers.

Residual maternal antibodies neutralize vaccine organism before infection occurs, interrupting immune response.
Causes primary vaccine failure in 15 percent of measles vaccine recipients, making subsequent doses necessary.
Concomitant diarrhea and competition by other enteroviruses reduce vaccine take for oral poliovirus vaccine.
Severe congenital or acquired immunodeficiency syndrome prevents adequate immune response generation.

Interruptions in vaccine cold chain damage heat-sensitive or freeze-sensitive formulations, leading to absent immunogenicity.
Inadequate antigen dose fails to circumvent inhibitory influence of maternal antibodies.
Polysaccharide vaccines fail to induce germinal centers, limiting memory cell generation and causing rapid secondary failure.

Defined as varicella illness developing greater than 42 days post-immunization.
Manifests typically 2 to 5 years following vaccination due to waning immunity.
Disease remains mild, exhibiting fewer than 50 maculopapular lesions, low fever, and shorter illness duration.
Risk factors include vaccination below 15 months of age, steroid administration, and increasing time since immunization.
Two-dose schedule effectively reduces primary vaccine failure risk and provides sustained protection against breakthrough disease.

Protective efficacy wanes significantly over 6 to 12 years following primary immunization.
Represents classic secondary vaccine failure.
Necessitates booster doses during childhood and adolescence to sustain protective antibody titers.