Influenza vaccination: Uptake and associations in a cross-sectional study of children with special risk medical conditions

Abstract

Objective

To determine uptake of influenza vaccination in children with special risk medical conditions (SRMC) and to explore associations with vaccination.

Design

Cross-sectional study.

Setting/participants

Parents of children with a SRMC attending either outpatient department clinics or being an inpatient at the Women’s and Children’s Hospital (WCH), Adelaide, Australia from September 2015 to February 2016 were recruited using convenience sampling.

Methods

Data were collected using a face-to-face survey. Influenza vaccination was verified with providers. Characteristics associated with uptake were explored using univariable and multivariable analyses.

Results

There were 410 participants with complete data. Confirmed influenza vaccination at least once in the last two years was 50%, annual uptake was 32.8%. 63.9% of parents were aware of the vaccination recommendation and 57.9% had been recommended by a specialist or general practitioner (GP). Characteristics strongly associated with uptake included: receiving a recommendation from a specialist or GP and having a parent receive the influenza vaccine annually.

Conclusions

Despite a long standing funded program, influenza vaccination uptake in children with SRMC is suboptimal. Parental vaccination behaviour, along with medical practitioner recommendation, particularly specialist recommendation, appear to be key influences in facilitating vaccination. Potential interventions could target the family rather than just the individual child. Understanding the barriers to recommendation from the perspective of general medical practitioners and specialists who treat these children is needed.

Introduction

Influenza is a serious disease, with seasonal peaks contributing to large numbers of hospitalisations, associated morbidity and mortality worldwide [1], [2], [3]. Numerous medical conditions increase an individual’s risk of acquiring influenza infection or developing serious complications, including lung and cardiac diseases, neurological disorders, low immunity and other conditions that require regular medical follow-up or hospitalisation such as diabetes [4]. Influenza vaccination is the single most important measure to prevent or attenuate infection and prevent mortality. Several countries recommend the seasonal influenza vaccine annually for children with special risk medical conditions (SRMC) [5], [6], [7]. In Australia, SRMCs are defined in the Australian Immunisation Handbook [4] based on recommendations of the Australian Technical Advisory Group on Immunisation and approved by the National Health and Medical Research Council [8]. Individuals with these conditions have been funded under Australia’s National Immunisation Program (NIP) to receive the vaccine annually since 2010 [8] with the National Seasonal Influenza Vaccination Program (NSIVP) generally commencing in the first month of autumn each year. However, the seasonal influenza vaccine is not routinely recorded on the Australian Immunisation Register (AIR) and consequently, there is little data about vaccine coverage, including in children with SMRC.

Most studies reporting influenza vaccine coverage in Australian children were prior to the 2009/2010 pandemic and serious adverse events that occurred in 2010 with use of the BioCSL Fluvax vaccine [9], [10]. Two recent studies, both from New South Wales in children with SRMC, estimated coverage to be 41–42% [11], [12]. In contrast, a study of hospitalised children in Western Australia, found coverage with a SRMC to be 30.1% [13]. Western Australia implemented a funded influenza vaccine program for children <6 years of age in 2010, with all other states commencing a similar program in 2018.

Besides reporting on coverage, understanding facilitators associated with uptake is useful in order to tailor vaccination recommendations, identify program weaknesses and guide policy changes. Studies from overseas [14], [15], [16], [17], [18], [19] and Australia [12] suggest that provider recommendation is critical to uptake.

Current recommendations are for children aged 6 months to <9 years receiving influenza vaccine for the first time to receive 2 doses in the first year to maximise the immune response to the vaccine [4]. The upper age limit was <10 years of age until March 2015 [20]. However, there is limited data on adherence to this recommendation. A coverage report suggests that only half of the children aged <5 years with a first documented dose on the AIR also received their second dose in the same year [21].

The objectives of this study were to determine levels of influenza vaccination uptake in children with SRMC, and to explore characteristics associated with receipt of the influenza vaccine in children with SRMCs.