This study focused on identifying strategies and approaches that GPs might use or influence to improve vaccine uptake. However, numerous patient-related factors also affect flu vaccine uptake. Highly mobile or ethnically diverse populations may prove very difficult to contact and target for flu vaccination. It is also likely that a minority of patients will always refuse or miss vaccination, no matter how much GPs strive to provide it. Public perception of influenza as a significant threat to health and of vaccination as an effective preventive strategy is associated with higher uptake.²⁴ People who receive information about these factors from official health sources (particularly GPs or nurses in the primary care setting) and who think that others want them to be vaccinated are more likely to get vaccinated.^{11 24 25} In line with this, flu vaccination uptake is greater among older people and others who make routine use of hospital and community care services.²⁶ Unsurprisingly, fear of side effects of vaccination is a strong negative influence, while lack of general motivation and ignorance about the recommendations are other commonly reported barriers to both seasonal and pandemic vaccination.^{27 28} However, when intensive recall stimuli and information are provided to at-risk patients, as few as 3.5% will refuse vaccination, suggesting that patient attitudes are malleable and should not present a barrier to achieving the CMO's aims.²⁹ Our results strongly support the provision of personal invitations for all patients (in alternative languages and/or formats, if required), as advised by the CMO.²² However, we found little evidence of benefit from offering very early (before 8:00), late (after 18:00) or weekend appointments. This contradicts some current guidance²² and is likely to be of financially relevance for practices. Our findings with respect to the flu vaccination of pregnant women are also important. Although administering flu vaccine is not part of the current role of many midwives, it is logical that the ability both to discuss and to provide vaccination to pregnant women would increase uptake in this risk group by removing the need for referral and attendance at a separate clinic: our analyses now support this logic. However, if midwives were to provide influenza vaccination outside of the practice setting, it would be essential for reliable records of this to be transferred to the GP.

The need for good communication with patients, to encourage the uptake of flu vaccination, is axiomatic. However, several statistically significant outcomes of our analyses have not previously been described and are directly or indirectly associated with the quality or extent of communication within practices. The production of a written review of practice performance might be associated with higher flu vaccination rates for a number of reasons. Production of such a report indicates that at least one member of staff must be able to access and manipulate the relevant data using their practice's computer systems and is motivated to do so. Subsequent dissemination of the report allows staff to become aware of their practice's performance and identify areas for improvement. Only 20% of practices in our study produced a written report of vaccine uptake rates and this strategy is not currently recommended in the CMO guidance for England. Our results also indicate that each practice should nominate lead members of staff for organising the practice's influenza vaccination campaign (as advised by the English and Scottish CMOs^{22 23}) and for identifying at-risk patients from the practice database. This is supported by a recently published study from the USA, which suggested that effective use of electronic databases by a skilled data manager could increase the rate of flu vaccination by over 10%.³⁰ The ability to perform a modified or in-house search of the practice's patient database is unlikely to improve the simple process of identification of those aged over 65 years. However, a member of staff who is thoroughly familiar with the IT system may be more able to contribute to improved rates of vaccination by, for example, monitoring levels of appointment bookings and vaccine uptake in real-time throughout the campaign; generating automatic invitation and reminder letters, text messages or emails; creating alert flags on the patient record to promote opportunist vaccination. Our study's findings also suggest that the effectiveness of a practice's flu vaccination campaign is increased when staff promote vaccination among themselves, an effect which may arise from increased motivation for the campaign as a whole or through communication of their positive attitude to at-risk patients. This supports the findings of previous studies and should thus contribute to an increased impetus to encourage vaccination of staff.^{31 32}

The relationship between staff motivation and practice performance is neither simple nor exclusive. Individuals may have different motivations and their interaction within a larger team may produce variable outcomes. We do not argue that introducing written reports and/or tailoring the practice search strategies would necessarily increase motivation. However, in practices where these actions are not already undertaken, their introduction would ensure that staff become more aware of the practice's performance and the underlying mechanisms that influence it. Having found a highly significant correlation of these strategies with increased vaccine uptake, we propose that increased awareness and knowledge may help to increase staff motivation. However, our study was not designed to measure motivation per se or its effects in isolation and this would be an interesting (though challenging) area for further study.

There is currently a significant financial risk for practices attempting to improve their vaccination rates. As practices are only reimbursed on the basis of the number of vaccines administered, they face a financial penalty if they buy more doses than are used and sale-or-return schemes are usually limited to a few per cent of the vaccine doses in the overall order. Perhaps as a result, we have found that almost 50% of practices currently halt their vaccination campaigns due to exhaustion of vaccine stocks. A central procurement strategy for flu vaccines, which has recently undergone consultation by the Department of Health, should remove this financial stricture and allow practices to aim for much higher vaccination rates without risking financial penalty.³³ However, this will also result in the loss of a significant proportion of practices' funding for flu vaccination (ie, which is currently derived from any discrepancy between tariff price and purchased price for the vaccine itself). Considerable effort and resources are required to deliver a successful flu vaccination campaign, and our findings indicate that practices' efforts can be influenced by financial motivations. The pursuit of QOF targets for flu vaccination requires practice staff to be able to perform complex interrogations of their patient database and to be aware of rates of vaccine uptake while the flu vaccination campaign is progressing. Our data suggest that pursuing the QOF targets may motivate practices to maintain vaccine stocks and encourage extra patients to receive vaccine. We would not advise that practices should automatically stop vaccinating patients once their QOF targets have been attained. However, our findings suggest that a scale of financially supported targets applicable across all patient groups, or the inclusion of flu vaccination of all at-risk patients in the QOF scheme, might be a powerful tool to increase flu vaccine uptake.