Vaccine effectiveness of live attenuated and trivalent inactivated influenza vaccination in 2010/11 to 2015/16: The sive ii record linkage study

Colin R. Simpson* (Corresponding Author), Nazir I. Lone, Kim Kavanagh, Tanya Englishby, Chris Robertson, Jim McMenamin, Beatrix Von Wissman, Eleftheria Vasileiou, Christopher C. Butler, Lewis D. Ritchie, Rory Gunson, Jürgen Schwarze, Aziz Sheikh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Background: There is good evidence of vaccine effectiveness in healthy individuals but less robust evidence for vaccine effectiveness in the populations targeted for influenza vaccination. The live attenuated influenza vaccine (LAIV) has recently been recommended for children in the UK. The trivalent influenza vaccine (TIV) is recommended for all people aged≥65 years and for those aged<65 years who are at an increased risk of complications from influenza infection (e.g. people with asthma). Objective: To examine the vaccine effectiveness of LAIV and TIV. Design: Cohort study and test-negative designs to estimate vaccine effectiveness. A self-case series study to ascertain adverse events associated with vaccination. Setting: A national linkage of patient-level general practice (GP) data from 230 Scottish GPs to the Scottish Immunisation & Recall Service, Health Protection Scotland virology database, admissions to Scottish hospitals and the Scottish death register. Participants: A total of 1,250,000 people. Interventions: LAIV for 2- to 11-year-olds and TIV for older people (aged≥65 years) and those aged<65 years who are at risk of diseases, from 2010/11 to 2015/16. Main outcome measures: The main outcome measures include vaccine effectiveness against laboratory-confirmed influenza using real-time reverse-transcription polymerase chain reaction (RT-PCR), influenza-related morbidity and mortality, and adverse events associated with vaccination. Results: Two-fifths (40%) of preschool-aged children and three-fifths (60%) of primary school-aged children registered in study practices were vaccinated. Uptake varied among groups [e.g. most affluent vs. most deprived in 2- to 4-year-olds, odds ratio 1.76, 95% confidence interval (CI) 1.70 to 1.82]. LAIV-adjusted vaccine effectiveness among children (aged 2-11 years) for preventing RT-PCR laboratoryconfirmed influenza was 21% (95% CI -19% to 47%) in 2014/15 and 58% (95% CI 39% to 71%) in 2015/16. No significant adverse events were associated with LAIV. Among at-risk 18- to 64-year-olds, significant trivalent influenza vaccine effectiveness was found for four of the six seasons, with the highest vaccine effectiveness in 2010/11 (53%, 95% CI 21% to 72%). The seasons with non-significant vaccine effectiveness had low levels of circulating influenza virus (2011/12, 5%; 2013/14, 9%). Among those people aged≥65 years, TIV effectiveness was positive in all six seasons, but in only one of the six seasons (2013/14) was significance achieved (57%, 95% CI 20% to 76%). Conclusions: The study found that LAIV was safe and effective in decreasing RT-PCR-confirmed influenza in children. TIV was safe and significantly effective in most seasons for 18- to 64-year-olds, with positive vaccine effectiveness in most seasons for those people aged≥65 years (although this was significant in only one season). Future work: The UK Joint Committee on Vaccination and Immunisation has recommended the use of adjuvanted injectable vaccine for those people aged≥65 years from season 2018/19 onwards. A future study will be required to evaluate this vaccine. Trial registration: Current Controlled Trials ISRCTN88072400.

Original languageEnglish
Pages (from-to)1-92
Number of pages92
JournalHealth Technology Assessment
Issue number67
Publication statusPublished - Dec 2020

Bibliographical note

The authors would like to thank staff at Albasoft Ltd, HPS, the WoSSVC, the Asthma UK Centre for
Applied Research and the ISD electronic Data Research and Innovation Service team, and would also like to thank the GPs contributing data to the study and members of the Independent Steering Committee and Asthma UK Centre for Applied Research patient and public involvement team for overseeing this work.

Data Availability Statement

All data requests should be submitted to the corresponding author for consideration. Access to
anonymised data may be granted following review.


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