Anti-pertussis antibody kinetics following DTaP-IPV booster vaccination in Norwegian children 7–8 years of age

Abstract

At the age of 7-8 years a booster of diphtheria, tetanus, acellular pertussis and polio vaccine is recommended for children in Norway. In this cross-sectional study we have analysed the antibody levels against pertussis vaccine antigens in sera from 498 children aged 6-12 years. The purposes of this study were to investigate the duration of the booster response against the pertussis vaccine antigens pertussis toxin (PT) and filamentous haemagglutinin (FHA); to determine the presence of high levels of pertussis antibodies in absence of recent vaccination; and to analyse how booster immunisation may interfere with the serological pertussis diagnostics. Prior to the booster the IgG antibody levels against PT revealed a geometric mean of 7.3IU/ml. After the booster the geometric mean peak anti-PT IgG response reached to 45.6IU/ml, followed by a steady decline in antibody levels over the next few years. The IgG anti-FHA levels followed the anti-PT IgG profiles. Three years after the booster the geometric mean IgG levels were only slightly above pre-booster levels. Prior to the booster 44% of the sera contained ≤5IU/ml of anti-PT IgG compared to18% 3 years after and 30% 4 years after the booster. When recently vaccinated children were excluded, 6.2% of the children had anti-PT IgG levels above 50IU/ml which may indicate pertussis infection within the last 2 years. This study indicates that the currently used acellular pertussis vaccines induce moderate immune responses to the pertussis antigens and that the antibodies wane within few years after the booster. This lack of sustained immune response may partly be responsible for the increased number of pertussis cases observed in this age group during the last years.

Early intervention in pertussis outbreak with high attack rate in cohort of adolescents with complete acellular pertussis vaccination in Valencia, Spain, April to May 2015

“…This is consistent with the results of other studies where risk is seen to increase three years after the last acellular dose [5]. These findings should be incorporated into vaccination strategies decisions and they should promote research on new anti-pertussis vaccine components with greater effectiveness and longer protection.…”

“…In recent years, an increase in the number of cases has been noticed in different European countries, including Spain, in spite of good vaccination coverage [3,4]. Studies have also indicated a decline in antigenic response to acellular vaccine already few years after vaccination booster and this could result in the near future in vulnerable age cohorts vaccinated exclusively with it [5,6]. This highlights that even a full course of acellular vaccine in line with the present vaccination schedules and good coverage may not confer sufficient protection to adolescents, and that there continues to be a risk of epidemic waves each three to four years [7,8].…”

Th1 versus Th2 T cell polarization by whole-cell and acellular childhood pertussis vaccines persists upon re-immunization in adolescence and adulthood

“…Both aP and wP induce an increase in antibody titers against all aP components [11–14]. Adults originally primed with wP remain seropositive for multiple pertussis antigens up to 36 months following vaccination, with antibody titers at greater levels than at pre-vaccination [15].…”

Persistence of Antibodies against Diphtheria, Tetanus, Pertussis, and Poliovirus Types I, II, and III Following Immunization with DTaP Combined with Inactivated Wild-Type Polio Vaccine (DTaP-wIPV)

“…Zepp et al (17) reported that a preschool booster reduced the total number of patients with pertussis in all generations, not only in the target group of school-aged children, because of indirect effects. In Norway, anti-PT antibodies were investigated at 6-12 years of age, and the results indicated that the level of immunity against pertussis was low at 5 years after the primary vaccination and that the DTaPbooster administered at 7-8 years generated a moderate anti-pertussis immune response that waned to near prebooster levels in a few years (18). Although a pre-school dose is administered at 4 years of age in the U.S., the highest incidence was in children aged 7-14 years, peaking at 10 years of age (9).…”