Rapid influenza molecular testing in secondary care and influenza surveillance in England: Any impact?

Abstract

Introduction The use of rapid molecular testing for influenza diagnosis is becoming increasingly popular. Used at the point of care or in a clinical laboratory, these tests detect influenza A and B viruses, though many do not distinguish between influenza A subtypes. The UK Severe Influenza Surveillance System (USISS) collects surveillance data on laboratory‐confirmed influenza admissions to secondary care in England. This study set out to understand how rapid influenza molecular testing was being used and how it might influence the availability of subtyping data collected on influenza cases admitted to secondary care in England. Methods At the end of the 2017/2018 and 2018/2019 influenza seasons, a questionnaire was sent to all National Health Service Hospital Trusts in England to evaluate the use of rapid influenza testing. Surveillance data collected through USISS was analysed from 2011/2012 to 2020/2021. Results Of responding trusts, 42% (13/31) in 2017/2018 and 55% (9/17) in 2018/2019 used rapid influenza molecular tests, either alone or in combination with other testing. The majority of rapid tests used did not subtype the influenza A result, and limited follow‐up testing occurred. Surveillance data showed significant proportions of influenza A hospital and intensive care unit/high dependency unit admissions without subtyping information, increasing by approximately 35% between 2012/2013 and 2020/2021. Conclusions The use of rapid influenza molecular tests is a likely contributing factor to the large proportion of influenza A hospitalisations in England that were unsubtyped. Given their clear clinical advantages, further work must be done to reinforce these data for public health through integrated genomic surveillance.

An intercountry comparison of the impact of the paediatric live attenuated influenza vaccine (LAIV) programme across the UK and the Republic of Ireland (ROI), 2010 to 2017

“…The increasing and wider use of rapid point-of-care testing in secondary care may have also contributed to an increased detection in influenza particularly in the most recent seasons of the study. 27 Despite the apparent reduced impact against severe disease, smaller percentage increases in ICU influenza admissions were noted amongst fully vaccinating countries in the post-programme seasons in our findings, suggesting a likely impact effect.…”

“…This could be a potential explanation of our findings where two of the post‐programme seasons (2014/2015 and 2016/2017) observed suboptimal matching of the influenza A(H3) subtype as well as being dominated by circulation of A(H3), which is known to affect the older population more adversely. The increasing and wider use of rapid point‐of‐care testing in secondary care may have also contributed to an increased detection in influenza particularly in the most recent seasons of the study 27 . Despite the apparent reduced impact against severe disease, smaller percentage increases in ICU influenza admissions were noted amongst fully vaccinating countries in the post‐programme seasons in our findings, suggesting a likely impact effect.…”