Persistence Of Vaccine-induced Immunity Research Articles

Common Genetic Variations Associated with the Persistence of Immunity following Childhood Immunization

Vaccines have revolutionized public health, preventing millions of deaths each year, particularly in childhood.Yet, there is considerable variability in the magnitude and persistence of vaccine-induced immunity. Maintenance of specific antibody is essential for continuity of vaccine-induced serological protection. We conducted a genome-wide association study into the persistence of immunity to three childhood vaccines: capsular group C meningococcal (MenC), Haemophilus influenzae type b, and tetanus toxoid (TT) vaccines. We detail associations between variants in a locus containing a family of signal-regulatory proteins and the persistence MenC immunity. We postulate a regulatory role for the lead SNP, with supporting epigenetic and expression quantitative trait loci data. Furthermore, we define associations between SNPs in the human leukocyte antigen (HLA) locus and the persistence of TT-specific immunity. Moreover, we describe four classical HLA alleles, HLA DRB1∗0301, HLA DQB1∗0201, HLA DQB1∗0602, and HLA DRB1∗1501, associated with TT-specific immunity, independent of the lead SNP association.

Persistence of Vaccine-Induced Immunity in Preschool Children: Effect of Gestational Age

BackgroundA program of immunization that ensures optimal development of acquired immunity should be carried out in all healthy newborns. The aim of the present study was to verify, at 2.5–3 years after the last dose of basic vaccination, if preschool children who have been delivered preterm and at term differ in their levels of post-vaccination protective antibodies.Material/MethodsHumoral response was assessed in 352 children (mean age: 5.22±0.34 years) who received a series of obligatory vaccinations in the period from birth to 2.5–3 years of age. Antibodies (in IgG class) against vaccine antigens – diphtheria (D), tetanus (T), pertussis (P), Haemophilus influenzae type b (Hib), poliomyelitis (IPV), measles, mumps, and rubella (MMR) – were measured using ELISA. The level of antibodies against hepatitis B (HBV) was assessed by chemiluminescence.ResultsAll children had been immunized according to the Polish National Vaccination Program. The group of 352 children eligible for the study included 46 (13.1%) preschoolers delivered preterm (32–36 weeks of gestation), and 306 (86.9%) born at term (37–42 weeks of gestation). All children maintained seroprotective antibody levels against polioviruses type 1, 2, and 3 (>12 mIU/mL), and against measles antigens (>300 U/mL). No statistically significant differences were found in the proportions of preschoolers born preterm and at term who were seroprotected against other vaccine antigens.ConclusionsAmong preschool children who were immunized according to chronological age, those we were born late preterm do not seem to differ in vaccine-induced immunity from those who were born full-term.

The measurement and interpretation of age-specific vaccine efficacy.

The age-specific efficacy of a vaccine depends upon the mechanism of vaccine action and the force of infection in the unvaccinated subpopulation. Consequently, inferences concerning the persistence of vaccine-induced immunity cannot in general be made directly from age-specific vaccine efficacy estimates. The definition, estimation and interpretation of age-specific vaccine efficacy measures are discussed using simple models of vaccine action. The methods are applied to data on measles and pertussis vaccines.

Challenge with rubella virus after loss of detectable vaccine-induced antibody.

Studies were conducted of experimental challenge with rubella virus in vaccinees whose possession of vaccine-induced antibody after vaccination had been documented and whose antibody level had become undetectable or very low over time. The challenge virus was the Howell strain, which had been shown to produce typical clinical and laboratory features of rubella in susceptible persons. The challenge of the vaccinees resulted in local viral replication in all but one; in viremia, a primary immunologic response, and a secondary antibody response in some; and usually in illness without a rash or in subclinical infection. The results emphasize the importance of continuing careful clinical and laboratory surveillance of vaccinees for determining the persistence of vaccine-induced immunity and of considering methods for identifying and revaccinating the minority of vaccinees who lose such immunity.