Rhian McNaughton, Elizabeth Lynn, Vicki Osborne, Saad Shakir

Background

An active surveillance study was performed at the start of the 2014/2015 influenza season following publication of EMA guidance for enhanced safety surveillance of influenza vaccines.

Objectives

To rapidly detect a clinically significant change in the frequency and/or severity of expected “reactogenicity” and other adverse events of interest (AEIs) during the first 14 days post vaccination with intranasal QLAIV (Fluenz Tetra®).

Methods

Children and adolescents vaccinated with QLAIV were recruited to this prospective observational cohort study through GPs or schools in pilot areas in England during a mass influenza vaccination programme. Three age groups with 100 vaccinees in each were planned: Group 1: 2-4 years, Group 2: 5-10 years, Group 3: 11-17 years. Participants completed simple online or postal questionnaires detailing exposure, covariates (e.g. medical conditions) and targeted outcome information about AEIs (primary outcome). AEI summary descriptive statistics, crude incidence risks and incidence rates (IR) per 1,000 patient-weeks (95%CI) were calculated.

Results

With data collected from September to November 2014, the cohort comprised 282 participants (Group 1: n=143; Group 2: n=103; Group 3: n=36). The most frequently reported AEI was nasal congestion in all age groups (Group 1: n = 67 (46.9%), IR: 317.3 (244.2, 412.3); Group 2: n = 46 (44.7%), IR: 264.6 (189.1, 370.3); Group 3: n = 15 (41.7%), IR: 295.2 (174.8, 298.4). Although four hypersensitivity type reactions were reported (Group 1: n = 1; Group 2: n = 2; Group 3: n = 1), on follow-up none was a true allergic reaction, serious or required hospitalisation.

Conclusion

No apparent safety signal was detected from the small amount of data collected. This study demonstrates that the methodology applied is well suited to rapidly monitor the incidence of AEIs with QLAIV, minimising any additional workload for healthcare professionals.