Introduction: The live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV; Imojev Ò) has been approved in South Korea for use in subjects aged C 12 months since 2015. As part of the license agreement, a post-marketing surveillance study was undertaken to actively monitor the safety profile of JE-CV in the Korean population. Methods: An observational, active safety surveillance study was conducted from 3 April 2015 through to 2 April 2019 at 12 centers in South Korea. Subjects aged C 12 months who received a single dose of JE-CV (primary or booster) during a routine healthcare visit were recruited and followed up for solicited reactions (7 and 14 days for injection site and systemic reactions, respectively), non-serious unsolicited adverse events and serious adverse events within 42 days after vaccination. Results: Overall, 810 subjects who received JE-CV were included in our analysis, the majority received the vaccine as a primary vaccination (94.9%; 769/810). There were 179 solicited reactions reported by 111 subjects; the majority of solicited reactions occurred within 0-3 days (80.4%; 144/179), were of 1-3 days' duration (79.3%; 142/179) and of grade 1 intensity (70.9%; 127/179). There were three grade 3 adverse reactions (irritability, pyrexia and malaise); all resolved within a few days. The incidence of solicited reactions were highest in those aged 12 to \ 24 months (34.7% [52/150] subjects; 107 events) and 2 to \ 10 years (17.8% [8/45] subjects; 14 events). All unsolicited adverse events (serious and non-serious) were unrelated to vaccination. There were no discontinuations due to adverse reactions/events. Conclusion: JE-CV has a good safety profile under practice conditions in South Korea. No new safety issues were identified.

Introduction Hepatitis A, caused by hepatitis A virus (HAV), is one of the leading causes of acute hepatitis in South Korea. Avaxim ® 160U is an inactivated hepatitis A vaccine that has been proven to be highly effective and well tolerated. It is licensed for use in more than 90 countries, and was approved for use in South Korea in 2011. Clinical trial and approval processes may not fully assess the safety and efficacy of a vaccine. Post-marketing surveillance (PMS) aims to provide a complete safety profile of a vaccine in a real-life setting. PMS trials are mandatory in South Korea to retain drug licensure. Methods This post-marketing observational study (NCT01838070) was conducted over 4 years at 16 centres in South Korea, and aimed to observe and record all types of adverse events (AE) occurring in an adult population after vaccination with Avaxim ® 160U. This included solicited events, unsolicited non-serious events, unexpected events and serious events. Results Case report forms were collected from 614 vaccinees, all of whom completed 30 days of follow-up post-vaccination, of whom 36 (5.9%) experienced 53 solicited and unsolicited AEs, 17 (2.8%) experienced 22 of the solicited AEs, while there were no reports of AEs of severe intensity. A total of 31 unsolicited AEs were reported in 22 patients (3.6%), and no unexpected adverse drug reactions were reported. Conclusion No new safety issues were identified and the safety profile obtained from this study was comparable to that of previous studies for HAV vaccine. Trial Registration ClinicalTrials.gov identifier, NCT01838070. Funding Sanofi Pasteur.