A Post-Authorisation Safety Study (PASS) of ABRYSVO (Respiratory Syncytial Virus Stabilised Prefusion Subunit Vaccine) in Pregnant Women and their Offspring in a Real World Setting in Europe and UK

Study type

• Study topic:
  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Safety study (incl. comparative)
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Name of medicine:
  ABRYSVO
• Anatomical Therapeutic Chemical (ATC) code:
  (J07BX05) respiratory syncytial virus vaccines

  respiratory syncytial virus vaccines

Population studied

• Short description of the study population:
  We will select females from the data sources, who are pregnant at or beyond the 24th week of gestation after the launch of ABRYSVO. We will use the ConcePTION pregnancy algorithm to estimate the start and end date of pregnancy, or data analysis plan-specific algorithms if they exist. We will include ongoing pregnancies to avoid selection bias towards pregnancies that ended prematurely. In some data sources, pregnancy is only observed when pregnancy has ended, in that instance we will include only pregnancies that have at least 10 months of administrative follow up from the last menstrual period. These 10 months cover the gestational period plus a month to identify outcomes in offspring at birth.
• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)
• Special population of interest:
  Pregnant women
• Estimated number of subjects:
  600

Study design details

• Study design:
  This study is a retrospective comparative cohort study of pregnant women who receive ABRYSVO compared with an unexposed pregnant comparator group.
• Main study objective:
  The primary study objective is to estimate the incidence, birth prevalence, prevalence ratios and risk ratios (depending on the specific outcome) and time between vaccination and birth (live or non-live) of the following adverse pregnancy, maternal and birth outcomes in women who receive ABRYSVO during pregnancy (and their offspring), compared with a matched group of pregnant women who do not receive ABRYSVO during pregnancy (and their offspring).
• Setting:
  The setting for this study will include data sources from the VAC4EU multinational network. The VAC4EU study network comprises research organisations, public health institutes, and data access providers under the condition of being qualified and able to provide either access to relevant data and/or relevant expertise to the post-marketing monitoring of vaccines.
• Comparators:
  1) Women of any age who are pregnant;; 2) date of LMP +24 weeks is after start of study period (24 Aug 2023); ; 3) enrolled in the healthcare system for at least 12 months prior to time zero; ; 4) not vaccinated with Abrsyvo during pregnancy at matched time zero; ; 5) at least one day of follow up for maternal outcomes 6) at least 10 months of follow up for pregnancy and birth outcomes.
• Outcomes:
  Pregnancy outcomes:; - Preterm delivery or birth (less than 37 weeks) among livebirths classified as extremely preterm delivery or birth (less than 28 weeks), very preterm delivery or birth (28 to less than 32 weeks), and moderate to late preterm delivery or birth (32 to less than 37 weeks);; - Time between vaccination and birth among live and non-live births (vaccination date for the unvaccinated pregnant woman is the vaccination date of their matched vaccinated pregnant woman);; - Stillbirth among live and non-live births.; ; Maternal outcomes during pregnancy:; - Hypertensive disorders of pregnancy;; - Guillain-Barré Syndrome (GBS).; ; Birth outcomes (at birth):; - Low birth weight among live births;; - Small for gestational age among live births.
• Data analysis plan:
  Description of baseline characteristics for ABRYSVO exposed and comparator cohorts will be reported as means, standard deviations, medians and other quartiles for continuous variables and as counts and proportions for categorical variables. Missingness of lifestyle factors will also be described, as well as the duration of the look-back period. To describe the comparability of matched cohorts, we will estimate standardised differences; between ABRYSVO exposed and matched non-exposed cohorts for each baseline characteristic. For categorical variables with more than 2 levels, we will calculate an overall standardised difference across all levels. For pregnancy and birth outcomes, risk, prevalence and 95% confidence intervals (CIs) will be reported, for the time interval between vaccination and delivery, median and distributions will be provided. Detailed methodology for summary and statistical analyses of data collected in this study will be documented in a statistical analysis plan (SAP), which will be dated, filed and maintained by the sponsor.