Acellular pertussis vaccines effectiveness over time: A systematic review, meta-analysis and modeling study

Abstract

BackgroundAcellular pertussis vaccine studies postulate that waning protection, particularly after the adolescent booster, is a major contributor to the increasing US pertussis incidence. However, these studies reported relative (ie, vs a population given prior doses of pertussis vaccine), not absolute (ie, vs a pertussis vaccine naïve population) efficacy following the adolescent booster. We aim to estimate the absolute protection offered by acellular pertussis vaccines.MethodsWe conducted a systematic review of acellular pertussis vaccine effectiveness (VE) publications. Studies had to comply with the US schedule, evaluate clinical outcomes, and report VE over discrete time points. VE after the 5-dose childhood series and after the adolescent sixth-dose booster were extracted separately and pooled. All relative VE estimates were transformed to absolute estimates. VE waning was estimated using meta-regression modeling.FindingsThree studies reported VE after the childhood series and four after the adolescent booster. All booster studies reported relative VE (vs acellular pertussis vaccine-primed population). We estimate initial childhood series absolute VE is 91% (95% CI: 87% to 95%) and declines at 9.6% annually. Initial relative VE after adolescent boosting is 70% (95% CI: 54% to 86%) and declines at 45.3% annually. Initial absolute VE after adolescent boosting is 85% (95% CI: 84% to 86%) and declines at 11.7% (95% CI: 11.1% to 12.3%) annually.InterpretationAcellular pertussis vaccine efficacy is initially high and wanes over time. Observational VE studies of boosting failed to recognize that they were measuring relative, not absolute, VE and the absolute VE in the boosted population is better than appreciated.

Knowledge, attitudes and beliefs about vaccination in primary healthcare workers involved in the administration of systematic childhood vaccines, Barcelona, 2016/17

“…While the vaccine effectiveness responses we received were in line with available literature [20-22], it is alarming that some health professionals considered vaccines that are being administered to children as unsafe or even dangerous. The large number of missing responses associated with the HPV vaccine indicates a sense of doubt or unawareness about this vaccine’s proven safety and efficacy.…”

Pertussis Prevention: Reasons for Resurgence, and Differences in the Current Acellular Pertussis Vaccines

“…It was calculated that for every additional year after the last dose of DTaP, the risk of pertussis increased 1.33 times (95% CI 1.23–1.43), leading to the conclusion that 8.5 years after the last aPV dose, only 10% of children were still protected against disease. Similar results were reported in another meta-analysis including studies of aPVs administered according to the USA schedule (46). VE was compared after the childhood series (five doses) and after an adolescent booster dose (sixth dose).…”

“…Relative VE was defined as VE in the population given prior doses of an aPV and absolute VE was defined as VE in an aPV-naïve population. Absolute VE after the childhood series was 91% (95% CI 87–95%) but declined annually by 9.6% (46). Initial relative VE after adolescent boosting was 70% (95% CI: 54 to 86%) and declined by 45.3% annually.…”

Pertussis in the Association of Southeast Asian Nations: epidemiology and challenges

“…aP vaccines have been estimated to confer a shorter duration of immunity than wP vaccines (4-7 years vs. 5-14 years, respectively) (Kilgore et al, 2016). Other possible contributory factors include improved performance of laboratory diagnostic methods to identify cases (Kaczmarek et al, 2016), disease awareness among healthcare workers and in the general population (Hoffait et al, 2011;Wilder-Smith et al, 2007), adaptation of B. pertussis to vaccines or the human host (Hovingh et al, 2018;Breakwell et al, 2016;Hegerle and Guiso, 2014), lower efficacy/effectiveness of some vaccines (Fulton et al, 2016;Chit et al, 2018), and insufficient vaccination coverage. The World Health Organization (WHO) recommends national immunization programs (NIPs) using wP vaccines to continue using it.…”