(1142) Safety of the 9-valent HPV vaccine in pregnancy base on adverse events reported in VAERS

The 9-valent HPV vaccine is FDA-approved in persons age 9-45. ACOG and the CDC currently recommend vaccinating postpartum due to limited safety data in pregnancy. Pregnancy is a time when vulnerable populations seek routine healthcare, and thus presents an opportunity to offer vaccinations that might otherwise not be received. We aimed to examine adverse events reported in patients receiving the 9-valent HPV vaccine during pregnancy.

Study Design: The Vaccine Adverse Events Reporting System (VAERS) database available from the CDC was queried on 7/27/2022 for “exposure during pregnancy” to the 9-valent HPV vaccine. Cases were excluded if there was no information on pregnancy in the report, or the patient was not pregnant at the time of the vaccination. Individual reports were reviewed and data was extracted on gestational age (GA) at time of vaccination, and adverse pregnancy events. GA was recorded as a categorical variable.

Results: 285 reports were identified and 273 were included. 110 (40.3%) reports expressly stated that there were no adverse events following vaccination. Of the remaining 163, there were eight (4.9%) reports of mild maternal reaction (most commonly injection site pain), and one report of a serious maternal reaction (angioedema). The majority of reports (257, 94.1%) did not include the pregnancy outcome.  Of pregnancy-related events, there was one case of vaginal bleeding, four miscarriages, one elective abortion, no still births, and two congenital anomalies.  There were seven reports of live births. 168 (61.5%) reports included GA at the time of vaccination (Figure).

Conclusion:  Few cases of pregnancy-related adverse events were identified following administration of the 9-valent HPV vaccine. VAERS is an electively reported database, thus the incidence of these events could not be determined, and many reports were incomplete. Despite these limitations, the low numbers of adverse events are reassuring. Clinical trials are warranted to conclusively examine the safety and efficacy of HPV vaccination during pregnancy.