This analysis provides an overview of seasonal influenza VCRs in the UK between 2015 and 2020 among clinically at-risk adults aged 16–64 years. Although the VCR data for at-risk patients aged six months to under 65 years is stratified by age band by PHE and other stakeholders, this analysis aimed to describe vaccine uptake among adults (age 16 to 64 years) in clinical at-risk groups from the 2015–2016 influenza season to present. The study highlights that vaccine uptake among at-risk patients has remained stable over the past 5 years with little improvement in uptake rates over the five year period and is remains suboptimal.
Despite the national recommendations for annual influenza vaccination in clinical at-risk groups, VCRs have remained consistently below national ambitions over the past five influenza seasons. Only 48.0, 42.4, 44.1 and 52.4% of eligible patients in England, Scotland, Wales and Northern Ireland, respectively, received their annual influenza vaccination during the 2018–2019 influenza season. Similar and consistently low VCRs were also observed in pregnant women. These low VCRs are disappointing, given the increased risk of severe influenza and complications in these individuals. The analysis suggests that people in these groups would benefit from measures to increase the uptake of vaccination.
Influenza VCRs are lowest in patients with morbid obesity, chronic liver disease and splenic dysfunction. Reduced rates of influenza vaccine uptake in patients with morbid obesity have been reported elsewhere, regardless of patient age . This may be explained by the relatively recent (2015) inclusion of morbid obesity as a clinically relevant risk factor in the influenza NVP and the fact that general practitioners (GPs) were not reimbursed for vaccination of patients with morbid obesity until the 2017–2018 influenza season .
Influenza VCRs were highest among patients with diabetes, although these rates remained substantially below the national ambition of ≥75%. We suggest this higher uptake among diabetic patients when compared with other clinical at-risk groups could be attributed to the fact that this patient group has well-defined inclusion criteria leading to better identification in GP practice registers. In addition, patients with diabetes comprise one of the largest at-risk groups in terms of patient numbers in the entire at-risk population in the UK. Therefore, this group may have been targeted for specific patient education campaigns previously. For some clinical at-risk groups, there may be a lack of patient education materials explaining the risk of severe influenza infection and complications associated with their disease.
The UK is considered a world leader in vaccine surveillance with robust reporting in clinical practice. Most influenza vaccines are delivered via primary care and uptake data are extracted automatically from GP electronic health record systems onto the relevant platforms. Data collected includes those vaccinated by another healthcare providers including community pharmacy and secondary care (provided the GP patient electronic record is updated). PHE and associated stakeholders across the devolved nations are responsible for monitoring coverage of all vaccines in the national immunisation schedule, and there are no regional differences within countries in terms of vaccine uptake data collection. Aggregated data are reported by the vaccine providers and analysed and published on a regular basis and there is a minimal time lag in reporting.
Many countries consistently fail to achieve the target influenza VCR of 75% for populations at risk of complications as recommended by the WHO and the European Council [43, 52]. Results from a survey of seasonal influenza immunisation policies (2017–2018 influenza season) in European Union (EU) and European Economic Area (EEA) Member States with a temperate climate reports that all 30 Member States recommend influenza vaccination in older people and populations with chronic medical conditions, and 28 Member States recommend influenza vaccination in pregnant women . However, VCRs (2016–2017) for older populations as reported by 19 Member States (Denmark, Estonia, Finland, Germany, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, the Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and the UK) were below WHO targets (range 2.0 to 72.8%) . Similarly, VCRs for populations with chronic medical conditions as reported by seven Member States (Czech Republic, France, Ireland, the Netherlands, Norway, Portugal, and the UK) were also below WHO targets (range 15.7 to 57.1%) and VCR for pregnant women as reported in nine Member States (Belgium, Finland, Hungary, Ireland, Italy, Lithuania, Romania, Slovenia, and the UK) were below WHO targets (0.5 to 58.6%) .
A recent review of VCRs from four countries with influenza VCRs generally considered to be ‘high’ (Australia, Canada, UK and USA) concluded that suboptimal vaccination coverage is a complex issue that can be influenced by socio-demographic, programmatic and socio-psychological factors . A total of 42 key factors for a successful influenza vaccination programme were identified and clustered into five pillars:  Health Authority accountability, and strengths of the influenza programme,  facilitated access to vaccination,  healthcare professional accountability and engagement,  awareness of the burden and severity of disease and  belief in influenza vaccination benefit .
A variety of patient-level and systems-level factors are probably associated with seasonal influenza vaccine uptake among clinical at-risk groups in this UK focussed study. Patient-level factors such as perceived susceptibility to disease and perceived vaccine effectiveness are predictors of vaccine acceptance. There is evidence to suggest that patients in high-risk clinical groups are more likely to receive an influenza vaccine after they receive information on the benefits of vaccination to their own health compared with social benefits to others. This correlation is even stronger when the patient perceives themselves as personally at higher risk . In addition, system- and practice-level factors such as access to preventative care services can affect influenza VCRs in the UK. A recent study in a UK population of clinically higher risk patients highlighted access-related barriers, including timing, availability and location of appointments for vaccinations, which at least partially correlated with socioeconomic deprivation . Additional system-level factors included access to GP appointments throughout the year, with higher levels of vaccine uptake in patients with higher numbers of GP appointments per year, potentially indicating the key role that GPs play in vaccine uptake and that patients who seek healthcare support are more inclined to be vaccinated .
A lack of understanding of the severity of influenza-related complications can impact a patient’s decision to receive the influenza vaccine; pregnant women who were not UK citizens and whose first language is not English reported communication concerns, resulting in an inability to access information on vaccination from their healthcare providers .
Attitudes among patients in clinical at-risk groups affect vaccine uptake; patients of all ages in at-risk groups were reportedly less likely to be vaccinated following a season with a vaccine of low effectiveness, and patients aged under 65 years were less likely to receive a vaccine following a season of high influenza severity, compared with seasons of low severity . Similarly, there is evidence to suggest that the language used by healthcare professionals around herd immunity and a “one size fits all” approach to maternal vaccination contributes to a lack of knowledge, misconceptions and distrust of healthcare professionals among pregnant women from lower socioeconomic backgrounds .
Discrepancies in influenza vaccine uptake owing to socioeconomic status disparities have been highlighted elsewhere; higher rates of influenza-associated illness and hospitalisations, coupled with lower influenza vaccine uptake among Merseyside residents (a geographic area in the UK scoring high on Index of Multiple Deprivation taking into account housing, education, environment and crime) highlighted significantly higher influenza-related burden in people from more deprived neighbourhoods than in those from less deprived areas . Similarly, data on influenza vaccine uptake between 2011 and 2016 highlighted disparities based on ethnicity, sex, age, socioeconomic deprivation and comorbidities .
Socioeconomic discrepancies and other factors may explain the regional variation highlighted in this study; influenza VCRs in all high-risk patients ranged from 41.8% in London to 48.6% in Greater Manchester. Regional variations were also apparent among pregnant women, with only four of 191 CCGs achieving their vaccine uptake target of ≥55% in 2019–2020. Regional discrepancies in VCRs across the UK highlight a need for improved consistency in vaccine uptake recommendations and patient education.
Every year across the UK, a sophisticated campaign is developed which aims to improve uptake rates of influenza vaccination. The strategy, developed and published as part of the annual Flu Plan, sets out a coordinated and multi-channel approach to guide the implementation of an awareness campaign and provides partner organisations with information and resources ahead of the influenza season. Several patient associations and organisations representing at-risk populations, including the British Lung Foundation, British Heart Foundation, Diabetes UK and Age UK actively support and participate in the campaign and create customised campaign resources and messages.
A 2012, nationwide, cross-sectional survey of UK general practice identified several strategies and procedures associated with higher rates of influenza vaccine uptake in at-risk patients . For at-risk patients aged under 65 years, having a lead member of staff for planning the influenza campaign and producing a written report of the practice’s performance was predictive of an 8% higher influenza vaccination rate compared with practices that do not employ these strategies (54% vs 46%). The active involvement of midwives in providing influenza vaccination to pregnant women was also significantly associated with higher levels of vaccine uptake.
In 2018, the National Institute for Health and Care Excellence (NICE) published a guideline describing mechanisms to increase uptake of influenza vaccination among eligible populations, including people at high risk from influenza and its complications. These guidelines highlight the importance of a multi-component approach, raising awareness, and auditing and monitoring of vaccine uptake . In 2020, NICE subsequently published a structured overview of potential quality improvement areas for increasing the uptake of the influenza vaccine . Areas of improvement include addressing the scepticism around influenza vaccination, improving the delivery of advice and information (including online sources and social media), and tailoring advice and information.
Any intervention to increase vaccine uptake should be monitored and evaluated systematically, to guide development and wider implementation. Understanding the strategy or reasons behind vaccine uptake is not part of the scope of this study; the study does, however, highlight that uptake rates have not significantly changed in five years and strategies to improve uptake rates are required.
Provisional data for the ongoing 2020–2021 season suggest that seasonal influenza vaccine uptake has increased in all eligible populations, with the highest rates ever achieved in people aged ≥65 years. For at-risk patients aged 2–65 years, uptake was provisionally reported as 51.5%, a rate higher than the previous seven seasons. This data is encouraging, especially amongst groups most vulnerable to influenza and also most at risk for COVID-19 and might be a direct result of the COVID-19 pandemic. This data also supports the results of a recent observational study measuring the impact of the COVID-19 pandemic on acceptance of influenza vaccination in the 2020–2021 season. This UK-wide study, showed COVID-19 increased the acceptance of influenza vaccination in the 2020–2021 influenza season from 79.6 to 91.2% in those previously eligible .
Provisional data for the ongoing 2020–2021 season indicate that COVID-19 activity at a national level continued to increase while influenza activity, including GP consultations and hospital admissions, remained at or below baseline levels . This is most likely due to a combination of the higher rates of influenza vaccine uptake and precautions implemented to slow down COVID-19 transmission (social distancing, hand washing and mask-wearing) that may also reduce the spread of influenza, which, similar to COVID-19, is primarily transmitted through respiratory droplets and contact with contaminated surfaces. As these precautionary measures are relaxed over time, we suggest influenza infection will increase in future seasons.
Limitations of the study
It is important to note that the data collected for each of the devolved nations of the UK do not allow for a direct comparison, owing to slight differences in the data collection process. Data is collected from different data sources, including GP practices, schools, and Occupational Health Departments.
Other potential limitations are the exclusion of data from the prison population and healthcare and social workers if they were vaccinated outside of GP surgeries and not reported via the ImmForm system. There are were also challenges with recording patients owing to a change in GP supplier system in 2019–2020 and delays with reporting of patients vaccinated in pharmacies. Reporting of pregnant patients who receive the influenza vaccine is particularly challenging owing to delays in updating patients’ electronic records after birth or loss of pregnancy and the nature with which pregnant women enter and leave the risk group throughout the influenza season.
It is also important to note that many people will have more than one clinical risk factor that makes them eligible for influenza vaccination; for example, a patient may suffer from both diabetes and chronic heart disease. When viewing influenza vaccine uptake broken down by clinical risk group, it is important to keep in mind that the same patient may be present in a number of different risk groups; however, a patient will only be counted once in the overall total uptake figure.