We have had a number of queries about the accuracy of our flu searches over the past week. The following is an explanation of why some patients may have been invited for a vaccine when they do not appear to be eligible.


The flu eligibility searches have been extremely difficult to write this year as NHS England did not publish any business rules until the end of September (1 month after flu clinics started) and the migration from READ to SNOMED at the beginning of the year meant the EMIS searches from 2019/20 (that the Ardens searches are based upon) contained a significant number of errors. These errors occurred because READ codes do not always directly map to SNOMED codes. We knew about this.


When we released our searches we included a warning that advised they would not be 100% accurate. This is because the 2019/20 EMIS searches that ours are based upon contained over 8,000 clinical codes. We very carefully checked these codes and removed as many errors as possible. Our internal testing indicates that the Ardens searches are about 98% accurate. Some examples of the errors that we identified in the EMIS searches include:


  • The EMIS searches included all school age children within their eligible population. We have removed those who are not otherwise at risk as they are part of the school vaccination programme and GP practices are not paid to vaccinate this group.
  • EMIS did not include all appropriate BMI codes (they omit the main ‘BMI’ code and just use those which are e.g. ‘Obese’. We have ensured that all patients with appropriate BMI correctly coded are included.
  • EMIS did not include the CHD register – these patients are eligible for a flu vaccine under QOF so need to be recalled so we have included them.
  • EMIS did not include all preparations of e.g. methotrexate and azathioprine (immunosuppressed patients) which means some are not included who should be.
  • EMIS did not include Learning Disabilities patients that should be included.
  • We have included some additional conditions (such as atrial fibrillation) as these patients are eligible for flu vaccine.
  • We have auto-included all COVID high risk (shielding) patients on the assumption that these patients will be eligible for a flu vaccine.
  • The EMIS searches included many clinical codes which were clearly not correct and we removed them (we have continued to remove newly identified incorrect codes over the past month and have released new versions of our searches multiple times to the Ardens Portal).


There would have been issues with accuracy had you used the Ardens searches or the EMIS searches (and you would have had significantly less accuracy if you had used the EMIS searches). We have really tried to offer practices the most accurate searches possible, but it is impossible to be 100% accurate when we are forced to guess the Business Rules


Please note that the "Seasonal Vaccination Required" alert in the pink "alert" box is an EMIS alert and nothing to do with Ardens.


In situations where a practice has invited a patient who is not included in the Enhanced Service business rules for payment, the following options exist:


  • Make a clinical judgement that they are eligible and add the code ‘Needs influenza vaccination’ (READ=9OX4, SNOMED=185903001), which will ensure they are included for payment under the ES.
  • Give the vaccine without adding the above code. You can still claim payment for the vaccine itself but you won’t be able to claim for the Enhanced Service payment.
  • Apologies and inform the patient that they are not in fact eligible for an NHS vaccine but may choose to have one privately.


Next year we are hoping the the Business Rules will be published in good time (i.e. before flu clinics actually begin) so we can offer more accurate searches.


If you require any further assistance on the process above, please contact Ardens support on: support-emis@ardens.org.uk.