Post-marketing surveillance study of the safety of the HPV-16/18 vaccine in Korea (2017–2021)

ABSTRACT Human papillomavirus (HPV) infection is associated with the risk of developing certain cancers, including cancers of the cervix, vulva, vagina, penis, anus, rectum, and oropharynx. In 2016, the bivalent HPV-16/18 vaccine was included in the Korea National Immunization Program. This vaccine protects against HPV types 16 and 18 and other oncogenic HPV types predominant in cervical and anal cancers. This post-marketing surveillance (PMS) study assessed the safety of the HPV-16/18 vaccine in Korea. The study was conducted in males and females aged between 9 and 25 years, from 2017 to 2021. Safety was measured in terms of frequency and intensity of adverse events (AEs), adverse drug reactions (ADRs), and serious adverse events (SAEs) after each vaccine dose. The safety analysis included all participants who were vaccinated as per prescribing information and who completed a 30-day follow-up after at least one dose. Data were collected using individual case report forms. The total safety cohort included 662 participants. A total of 220 AEs were reported in 144 subjects (21.75%), and there were 158 ADRs in 111 subjects (16.77%), with the most common being injection site pain in all cases. No SAEs or serious ADRs were reported. Most AEs were reported after the first dose and were injection site reactions with mild intensity that recovered. No individuals required hospitalization or an emergency department visit. Safety results showed that the HPV-16/18 vaccine was generally well tolerated in the Korean population, and no safety concerns were identified. ClinicalTrials.gov Identifier: NCT03671369. Plain Language Summary What is the context? Infection with human papillomavirus (HPV) is linked to the development of certain cancers. More specifically, HPV types 16 and 18 are predominant in cervical and anal cancers. In 2016, the HPV-16/18 vaccine was included in the National Immunization Program of Korea. What is new? The objective of this study was to evaluate the safety of the HPV-16/18 vaccine following its introduction in Korea. The study was conducted from 2017 to 2021 in young Korean men and women between 9 and 25 years of age. The study analyzed 662 participants, of whom: ∘ 144 reported 220 adverse events ∘ 111 reported 158 adverse drug reactions ∘ None reported serious adverse events The safety of the vaccine was measured after each dose as the number and intensity of: ∘ Adverse events, which are side-effects or unwanted reactions that might be associated with the use of the vaccine ∘ Adverse drug reactions, which are side-effects or unwanted reactions associated with the use of the vaccine ∘ Serious adverse events, which are reactions resulting in death, disability, are life-threatening, or require hospitalization (or prolongation of it). Most adverse events occurred following the first dose, were mild in intensity, and the participants recovered after a few days. Injection site pain was the most common adverse event following vaccination. What is the impact? The study showed that the HPV-16/18 vaccine is safe and generally well tolerated in Korean participants.