Jeroen Gorter

Background/Objectives: The Dutch National Immunisation Programme (NIP) aims to protect children against severe infectious diseases. As with all vaccines, adverse events following immunisation (AEFIs) may occur with the use of vaccines in the NIP. Safety of the vaccines is monitored by The Netherlands Pharmacovigilance Centre Lareb. This study aimed to systematically document AEFIs following administration of the MMR and DT-IPV vaccines, which are given simultaneously at the age of 9 years. Methods: A cohort event monitoring (CEM) study was performed, employing a longitudinal cohort design. Parents or guardians of 9-year-olds receiving the MMR and DT-IPV vaccines completed questionnaires following vaccination to report the presence or absence of AEFI. Results: AEFIs were reported for more than 73% of children given an MMR and DT-IPV vaccination. The great majority of the reported reactions were non-serious and self-limiting and consistent with those listed in the official product information for the MMR and DT-IPV vaccines. Injection site reactions were significantly more frequent at the site of the DT-IPV vaccination than the MMR vaccination. AEFIs were mostly perceived as little or moderately burdensome. Conclusions: AEFIs very frequently occurred after MMR and DT-IPV vaccination. This study provides further insight into the timing and duration of AEFIs after MMR and DT-IPV vaccination. In addition, detailed insight into the adverse event profile of these vaccines is provided, which helps to set realistic expectations for children and their parents or caretakers who follow the NIP and helps health professionals in their communication regarding AEFIs.

Background/Objectives: The aim of this study was to systematically assess Adverse Events Following Immunization (AEFI) among children following administration of the human papillomavirus (HPV) vaccine (Cervarix^®) included in the Dutch National Immunization Program (NIP) and to characterize the pattern and recurrence risk of AEFI after HPV revaccination. Methods: A longitudinal cohort event monitoring study, using patient-reported outcomes was used among recipients of the HPV vaccine at 10 years of age. Data were available for 3063 children following the first HPV vaccination and for 2209 children following the second HPV vaccination. Results: The most commonly reported AEFI following HPV vaccination were injection site reactions—reported by 46.5% of participants after the first dose and 31.9% after the second dose—followed by headache (8.2% and 3.9%, respectively) and joint pain (4.5% and 3.7%, respectively). Participants who received both HPV vaccine doses reported more AEFI after the first dose than after the second. Among girls, 61.2% reported at least one AEFI following the first dose, compared to 44.2% after the second dose. For boys, these percentages were 55.3% and 38.5%, respectively. This difference was statistically significant (p = 0.002). For some AEFI, such as injection site reactions, there appears to be a potential increased risk of recurrence following the second dose. Conclusions: This prospective longitudinal cohort event monitoring study showed that AEFI were more frequent after the first HPV dose and more frequent for girls compared to boys. An increased risk of recurrence was seen for AEFI, such as injection site reactions and headache. Furthermore, this study provides insight into the course of AEFI and the extent to which children were affected by these symptoms based on real-world data.