Background: In November 2012, the first cell cultured influenza vaccine, a trivalent subunit inactivated influenza vaccine (Flucelvax(®), ccIIV3), was approved in the US for adults aged ≥ 18 years.

Objective: To assess adverse events (AEs) after ccIIV3 reported to the US Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting surveillance system.

Methods: We searched VAERS for US reports after ccIIV3 among persons vaccinated from July 1, 2013-March 31, 2015. Medical records were requested for reports classified as serious (death, hospitalization, prolonged hospitalization, disability, life-threatening-illness), and those suggesting anaphylaxis and Guillain-Barré syndrome (GBS). Physicians reviewed available information and assigned a primary clinical category using MedDRA system organ classes (SOC) to each report. Empirical Bayesian data mining was used to identify disproportional AE reporting following ccIIV3.

Results: VAERS received 629 reports following ccIIV3 of which 313 were for administration of vaccine to persons <18 years. Among 309 reports with an AE documented, 19 (6.1%) were serious and the most common categories were 152 (49.2%) general disorders and administration site conditions (mostly injection site and systemic reactions) and 73 (23.6%) immune system disorders with two reports of anaphylaxis. Four reports of GBS were submitted. Disproportional reporting was identified for 'drug administered to patient of inappropriate age.'

Conclusions: Review of VAERS reports did not identify any concerning pattern of AEs after ccIIV3. Injection site and systemic reactions were the most commonly reported AEs, similar to the pre-licensure clinical trials. Reports following ccIIV3 in persons <18 years highlight the need for education of healthcare providers regarding approved ccIIV3 use.